WO2022099939A1 - High-viscosity oil exploitation method - Google Patents

High-viscosity oil exploitation method Download PDF

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Publication number
WO2022099939A1
WO2022099939A1 PCT/CN2021/075005 CN2021075005W WO2022099939A1 WO 2022099939 A1 WO2022099939 A1 WO 2022099939A1 CN 2021075005 W CN2021075005 W CN 2021075005W WO 2022099939 A1 WO2022099939 A1 WO 2022099939A1
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Prior art keywords
oil
low
viscosity oil
temperature
viscosity
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PCT/CN2021/075005
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French (fr)
Chinese (zh)
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钟立国
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中国石油大学(北京)
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Publication of WO2022099939A1 publication Critical patent/WO2022099939A1/en

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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G53/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes
    • C10G53/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G7/00—Distillation of hydrocarbon oils
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G7/00—Distillation of hydrocarbon oils
    • C10G7/06—Vacuum distillation
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/34—Arrangements for separating materials produced by the well
    • E21B43/40—Separation associated with re-injection of separated materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/22—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures
    • G01N25/26—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures using combustion with oxygen under pressure, e.g. in bomb calorimeter

Definitions

  • the invention relates to a method for exploiting high-viscosity oil, belonging to the technical field of petroleum exploitation.
  • Heavy oil and high pour point oil with high viscosity are generally recovered by thermal methods such as steam injection.
  • steam injection recovery methods include steam huff and puff, steam flooding and steam-assisted gravity drainage.
  • a boiler is also used to heat the purified water to generate high-temperature steam.
  • steam injection to recover heavy oil can achieve remarkable recovery effect, there are still many problems: (1) Steam injection recovery mainly heats the oil layer through high-temperature steam, which consumes a lot of energy, has high cost, and is harmful to the environment due to the production of a large amount of carbon dioxide and sewage.
  • the viscosity of heavy oil or high pour point oil can also be significantly reduced by mixing or dissolving crude oil with lower viscosity.
  • Viscosity reducers, etc. can improve the effect of wellbore viscosity reduction and wellbore lifting oil recovery or reduce the amount of thin oil blended (References 1-7).
  • thermal oil plugging removal method can relieve the organic damage of near-well formation and the effects of "splitting water and oil repelling" to improve oil well production (References 8-10).
  • the invention patent "A method and device for the integrated production and transportation of heavy oil catalytic upgrading and viscosity reduction” (Reference 12) provides an integrated method of heavy oil catalytic upgrading, viscosity reduction, production and transportation for the recovery of heavy oil reservoirs.
  • the light components are injected into the oil well by distillation to reduce the amount of dilute oil mixed with the wellbore when the wellbore is lifted.
  • the technical scheme is: according to the mass ratio of dilute oil to heavy oil 0.4-1.0, it is mixed into the wellbore to reduce the viscosity of the heavy oil; then the dilute heavy oil is extracted from the well, heated by a heat exchanger, and heated to 350 °C in a heating furnace, Enter the distillation tower, collect the distillate oil before 350°C, cool it down by the heat exchanger, and inject it into the wellbore to dilute the heavy oil for recycling; after 350°C, the heavy distillate oil is pumped to the heating furnace to heat up to 370°C-420°C, and then added by the pump
  • the upgrading catalyst is fed into the reaction tower together; in the reaction tower, under the action of the upgrading catalyst, the heavy distillate oil is catalytically upgraded to a low-viscosity heavy oil, and the upgraded heavy oil is directly exported after heat exchange.
  • the essence of this technical solution is to collect the pre-distillate oil at 350°C and cool it to 60°C and then inject it into the wellbore to reduce the viscosity of the heavy oil flowing from the formation through diluting.
  • the problem of increased oil viscosity and poor fluidity has not been proposed to inject light fractions into the formation to recover the high viscosity heavy oil in the formation.
  • the purpose of the present invention is to provide a high-viscosity oil recovery method, which is to reduce the viscosity of the high-viscosity oil by injecting the high-temperature low-viscosity oil into the formation of the high-viscosity oil reservoir, so as to realize low cost and low energy consumption. mining.
  • the present invention provides a method for producing high-viscosity oil, wherein the method is a method for injecting high-temperature low-viscosity oil or a combination of high-temperature low-viscosity oil and gas into a high-viscosity oil reservoir for huff and puff production; wherein , the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas reduces the viscosity of the high-viscosity oil in the formation by dissolving and heating, and increases the formation pressure; wherein, the high-temperature and low-viscosity oil includes the high-viscosity oil on-site One or more combinations of light fractions and middle distillates obtained by ground distillation; the light fractions are obtained by carrying out atmospheric distillation of the high-viscosity oil that has undergone dehydration and desalination; the middle fractions are obtained by dehydrating The heavy fraction obtained by atmospheric distillation of the desalted high
  • the method of the invention is to obtain high-temperature and low-viscosity oil by distilling the high-viscosity oil produced from the oil well, and then injecting the high-temperature and low-viscosity oil into the "stratum" of the oil reservoir, and then recovering the high-viscosity oil.
  • This method mainly utilizes the dilution and viscosity reduction of high-temperature and low-viscosity oil and the heating of oil layer to improve the fluidity of high-viscosity oil in the "formation" of the reservoir, and increase the formation pressure and oil displacement, thereby improving oil well production and reservoir recovery.
  • the low-viscosity oil produced from the low-viscosity oil reservoir in the oilfield can be recovered. (such as thin oil, etc.) or oil with a viscosity lower than the produced high-viscosity oil from other sources is mixed with the produced high-viscosity oil for distillation, that is, the mixture of the dehydrated and desalted high-viscosity oil and the low-viscosity oil is used for distillation. pressure distillation.
  • the gas includes one or a combination of two or more of natural gas, nitrogen, carbon dioxide and flue gas.
  • the injection of the combination of high-temperature and low-viscosity oil and gas into the formation of a high-viscosity oil reservoir is performed according to simultaneous injection of the two or The method of slug injection, wherein the simultaneous injection is performed by mixing high temperature and low viscosity oil and gas in the surface pipeline, wellhead mixing or bottom hole mixing, that is, the gas injection method can be surface pipeline mixing, wellhead mixing , bottom-hole mixing (respectively injected by the tubing and the annular space between the tubing and the casing, the mixing is at the bottom of the hole, the mixing refers to the mixing of gas and high-temperature and low-viscosity oil), and the slug injection is injected at high temperature and low viscosity.
  • the gas is injected in a slug type before the viscous oil, after the injection of the high temperature and low viscosity oil, or during
  • the temperature of the atmospheric distillation is 350°C-360°C.
  • the temperature of the vacuum distillation is 350°C-370°C.
  • the water content of the high-viscosity oil treated by dehydration and desalination is below 5%.
  • the atmospheric distillation and the vacuum distillation are carried out using high-viscosity oil produced from oilfield production wells after sedimentation treatment and dehydration and desalination treatment at the oil production site. carried out by means of local distillation.
  • the device for on-site distillation is composed of a settling tank with heat exchange function, a dehydration and desalination treatment tank, an atmospheric heating furnace, an atmospheric tower, a vacuum heating furnace, a vacuum tower ( Also known as vacuum distillation tower), buffer tank and pump, wherein the outlet of the sedimentation tank is connected to the inlet of the dehydration and desalination treatment tank through a pipeline, and the outlet of the dehydration and desalination treatment tank is connected to the atmospheric pressure heating furnace through a pipeline, and the atmospheric pressure heating furnace
  • the outlet is connected to the middle and lower part of the atmospheric tower through a pipeline, the bottom of the atmospheric tower is connected to the inlet of the decompression heating furnace through a pipeline, the outlet of the decompression heating furnace is connected to the lower part of the decompression tower through a pipeline, and the top of the atmospheric tower is connected to the lower part of the decompression tower through a pipeline.
  • the top of the decompression tower is connected with the inlet of the internal heat exchanger of the dehydration and desalination treatment tank and the inlet of the inner heat exchanger of the settling tank through the pipeline, the bottom of the decompression tower is connected with the vacuum residue output pipe, and the bottom of the dehydration and desalination treatment tank is connected.
  • the outlet of the heat exchanger is connected to the inlet of the low-viscosity oil buffer tank through a pipeline, the outlet of the low-viscosity oil buffer tank is connected to the wellhead of the high-viscosity oil production well, and the gas injection pipeline is also connected to the wellhead of the high-viscosity oil production well, so as to The fractions obtained by distillation are injected into production wells as high-temperature, low-viscosity oil.
  • in-situ distillation is implemented by placing the produced heavy oil or high-point oil and other high-viscosity oil at the oil production site, such as an oil production well site, a combined station, a transfer station, an oil refinery close to the oil field, etc. Distilled in situ.
  • the on-site in-situ distillation may include the following steps: injecting the high-viscosity oil produced from the production well into the settling tank through a pump for primary dehydration and desanding;
  • the desalination treatment tank is subjected to deep dehydration and desalination treatment, and the moisture content of the high-viscosity oil is preferably reduced to below 5%; 350°C-360°C) and then enter the atmospheric distillation tower for atmospheric distillation to obtain light fractions and heavy fractions, and then inject the heavy fractions into the vacuum heating furnace through a pump, and heat the high-viscosity oil (the vacuum distillation temperature is preferably 350 °C).
  • the production method injects high-temperature and low-viscosity oil into a high-viscosity oil reservoir formation through an oil pipe (preferably an insulated oil pipe).
  • an oil pipe preferably an insulated oil pipe.
  • the temperature of the high-temperature low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas injected into the high-viscosity oil reservoir formation is controlled below the safe injection temperature; the low-viscosity oil safe injection temperature is controlled according to the The minimum ignition temperature of the high temperature and low viscosity oil or the combination of high temperature and low viscosity oil and gas is determined.
  • the safe injection temperature of high temperature and low viscosity oil should take into account the injection into the reservoir to achieve better oil recovery effect, safe injection without fire, and lower than the temperature limit of oil well tubing string and tools and equipment.
  • the maximum injection temperature for simply injecting high-temperature and low-viscosity oil is preferably 100°C-240°C.
  • gas such as nitrogen, carbon dioxide, and inert gas
  • the gas can play a certain protective role.
  • the injection temperature of viscous oil can be increased to 240°C-300°C.
  • the minimum ignition temperature is estimated according to the ignition temperature of the high temperature and low viscosity oil or the combination of the high temperature and low viscosity oil and gas, and is determined through ignition simulation experiments.
  • the ignition simulation experiment is performed using an ignition simulation experimental device
  • the ignition simulation experimental device at least includes: a first injection pump, a first intermediate container, a high temperature box, a heating coil, a back pressure valve, visual combustion kettle, collector, gas cylinder (including air cylinder, oxygen cylinder and nitrogen cylinder, etc.), pressure gauge; wherein, the first injection pump is connected to the bottom of the first intermediate container through a pipeline, The upper outlet of the first intermediate container is connected to the inlet of the heating coil in the high temperature box through a pipeline, the outlet of the heating coil is connected to a back pressure valve through a pipeline, and the back pressure valve is connected to the visible combustion kettle through a pipeline Connected, the upper part of the visual combustion kettle is connected to the air cylinder, the oxygen cylinder and the nitrogen cylinder respectively through pipelines, a pressure gauge is installed on the pipeline, and the lower part of the visual combustion kettle is connected to the collector through pipelines.
  • the ignition simulation experiment device further includes a second injection pump and a second intermediate container, the second injection pump is connected to the bottom of the second intermediate container through a pipeline, and the upper outlet of the second intermediate container is connected through a pipeline Connected to the inlet of the heating coil in the high temperature box.
  • Some components of the above-mentioned ignition simulation experimental device preferably meet the following conditions: the maximum injection pressure of the injection pump is 30MPa-70MPa, the maximum heating temperature of the high temperature box is above 500°C, the temperature control accuracy is ⁇ 0.5°C, and the return temperature is ⁇ 0.5°C.
  • the pressure control range of the pressure valve is 0-70MPa, the length of the heating coil is 10m-20m, the diameter is 3mm, and the pressure resistance is 30MPa-70MPa.
  • the experimental pressure range of the visual combustion kettle is 0-10MPa, and equipped with pressure resistance A viewing window and a heating and temperature control system; the pipeline between the heating coil and the visible combustion kettle is provided with thermal insulation components, such as insulating materials.
  • the ignition simulation experiment includes the following steps:
  • composition of high-temperature and low-viscosity oil select the corresponding fraction and/or low-viscosity oil to make the experimental sample, or directly use the high-temperature and low-viscosity oil as the experimental sample; add the experimental sample to the first intermediate container, and pressurize the low-viscosity oil through the first injection pump.
  • the viscous oil is injected into the heating coil in the high temperature box (when gas needs to be injected, the gas is added to the second intermediate container, and the gas is mixed with the experimental sample by the second injection pump and then enters the heating coil in the high temperature box), high temperature box
  • the set temperature is the experimental temperature
  • the experimental sample heated to the experimental temperature is controlled at the experimental pressure level through the back pressure valve, so that the experimental sample of high temperature and high pressure enters the visual combustion kettle under the set temperature, pressure and gas environment, and is observed through the window Whether the experimental sample flowing into the visual combustion kettle catches fire;
  • the experimental pressure controlled by the back pressure valve is set according to the injection pressure of the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas on site, and the visual combustion
  • the temperature, pressure and gas environment of the kettle simulate the environment where leakage may occur; the heating temperature of the high-temperature box is determined according to the temperature at which the injected experimental sample may ignite.
  • the minimum ignition temperature is estimated according to the composition of the experimental sample, and adjusted up and down Carry out the ignition simulation experiment at a certain temperature (preferably 5°C-10°C), and adjust the heating temperature of the ignition simulation experiment according to the results of the ignition simulation experiment, until the minimum ignition temperature of the experimental sample is determined; multiplying the minimum ignition temperature by the safety factor can The corresponding safe injection temperature of the high-temperature and low-viscosity oil is obtained; preferably, the estimated ignition temperature can be estimated by performing a volume-weighted average or a mass-weighted average based on the composition of the experimental sample and the ignition temperature of each component.
  • the high-temperature and low-viscosity oil is heat-exchanged with the high-viscosity oil subjected to sedimentation treatment and/or dehydration and desalination treatment to lower the temperature to safe injection temperature.
  • the following methods can be used: exchanging heat with the high-temperature and low-viscosity oil through the sedimentation tank for producing the high-viscosity oil and the dehydration and desalting treatment tank, and at the same time as the high-viscosity oil is produced in the heating tank, the high-temperature and low-viscosity oil is appropriately cooled down to Safe injection temperature.
  • the production method provided by the present invention is to obtain high-temperature and low-viscosity oil fractions by in-situ distillation of crude oil produced from oil wells at the oil production site, and to pass appropriate heat exchange through a dehydration desalination treatment tank and a settling tank. Cool down to a safe injection temperature, and use low-temperature and low-viscosity oil, gas or water and other displacement media to replace the high-viscosity oil production well tubing and tubing with the gas in the casing annulus, and then inject the high-temperature and low-viscosity oil fractions into the reservoir through the tubing of the oil well. At the same time, other media such as gas can be injected into the stratum, and oil production can be carried out after stopping the injection and soaking for a period of time.
  • the mining method provided by the present invention may comprise the following steps:
  • the displacement medium includes one or two of low-temperature and low-viscosity oil, gas and water more than one combination;
  • gas is injected through the oil pipe and/or the oil jacket annulus, so as to expand the stratum swept range of the injected high-temperature and low-viscosity oil; wherein, the injection
  • the volume ratio of the gas to the low-viscosity oil under atmospheric pressure is preferably determined according to the injection amount of the low-viscosity oil, the solubility of the gas in the low-viscosity oil, the gas swept range, the formation fluid saturation in the swept range, and the oil formation pressure to be achieved;
  • the current cycle of production is terminated, and the next cycle of injection of high-temperature and low-viscosity oil or a combination of high-temperature and low-viscosity oil and gas is performed for huff and puff.
  • repeating the above steps (1)-(4) is called one cycle.
  • the recovery method comprises the following specific steps:
  • the high-temperature and low-viscosity oil after heat exchange is injected into the formation of the high-viscosity oil reservoir through the tubing of the high-viscosity oil production well.
  • the oil well is opened for production.
  • the high-viscosity oil diluted and heated by the injected low-viscosity oil flows to the bottom of the well. And production, improve the production speed and recovery rate of formation high-viscosity oil.
  • the extracted high-viscosity oil is re-distilled, injected, simmered and recovered, so as to carry out circulating huff and puff extraction, and the high-viscosity oil is recovered by on-site distillation.
  • the low-viscosity oil fraction in the medium and the auxiliary gas continuously develop the high-viscosity oil in the reservoir formation, so that the low-viscosity oil obtained by the distillation of the high-viscosity oil itself can be reinjected into the “belt” of the high-viscosity oil in the reservoir.
  • the water quality treatment of conventional steam injection production and boiler production of steam greatly reduce the production water volume, so that the production cost of high viscosity oil can be reduced to less than 1/2 of the steam huff and puff, and it has the advantages of environmental friendliness, which can be used to replace the existing high energy consumption. , High-cost steam huff and puff mining method.
  • step (1) and step c can be carried out in the following manner: before injecting high-temperature and low-viscosity oil, inject low-temperature, low-viscosity oil into a high-viscosity oil production well, preferably through an annulus of tubing and tubing and casing.
  • Substitute medium such as viscous oil, gas or water to displace the air in the annular space between the tubing and the tubing and casing, ensuring the safety of subsequent injection of high-temperature and low-viscosity oil.
  • the injection gas can be nitrogen, carbon dioxide, or the like.
  • the displacement method can directly inject low-temperature and low-viscosity oil, gas or water and other displacement media into the formation under high pressure through the oil pipe, the oil pipe and the casing annulus, and can also inject the low-temperature low-viscosity oil, gas or water and other displacement media from the oil pipe.
  • the gas such as air in the circulating displacement well can be produced from the tubing and casing annulus
  • the displacement medium such as low-temperature and low-viscosity oil, gas or water can also be injected from the tubing and casing annulus, and the gas such as air in the circulating displacement well can be produced from the tubing. .
  • the injection amount of the high-temperature low-viscosity oil, the injection amount of the low-viscosity oil when the high-temperature low-viscosity oil is combined with the gas is based on the viscosity of the high-viscosity oil, the oil The degree of reservoir exploitation and the type of oil well are determined.
  • the degree of recovery of the oil reservoir is characterized by the swept radius of the oil reservoir, and the swept radius of the oil reservoir is the distance from the outer boundary of the produced oil reservoir to the production well; when it is newly put into production
  • the swept radius of the reservoir can be 3m-5m, that is, the swept radius of the reservoir can be 3m-5m when the low-viscosity oil is injected into huff and puff in the first cycle of newly put into production vertical wells or directional wells;
  • the swept radius of the reservoir can be 1m-3m, that is, when the first cycle of newly put into production horizontal wells, branch wells and fishbone wells adopts low-viscosity oil injection and huff and puff production
  • the swept radius of the reservoir can be 1m-3m.
  • the injection intensity of the high-temperature and low-viscosity oil during huff and puff production of high-viscosity oil is the amount of high-temperature and low-viscosity oil injected per meter of oil layer period, or the combination of high-temperature and low-viscosity oil and gas
  • the amount of high temperature and low viscosity oil can be calculated according to the following formula:
  • I o [a+b ln(R/h)] ⁇ [c ln ln( ⁇ )-d]
  • I o is the injection strength of low-viscosity oil, m 3 /m; a and b are parameters related to the degree of reservoir production, c and d are parameters related to the viscosity of high-viscosity oil, which can be passed according to the target reservoir conditions.
  • the injection strength of the high temperature and low viscosity oil is:
  • I ho [1+0.15ln(R/h)] ⁇ [120lnln( ⁇ )-150]
  • I ho is the injection strength of high temperature and low viscosity oil, m 3 /m; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; ⁇ is the viscosity of high viscosity oil under formation conditions, mPa ⁇ s;
  • the injection strength of the high temperature and low viscosity oil is:
  • I ho [1+0.1ln(R/h)] ⁇ [12lnln( ⁇ )-15]
  • I ho is the injection strength of high temperature and low viscosity oil, m 3 /m; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; ⁇ is the viscosity of high viscosity oil under formation conditions, mPa ⁇ s.
  • the gas that is, during the injection of the high-temperature and low-viscosity oil or after the high-temperature and low-viscosity oil is injected , the volume ratio of the gas injected through the oil pipe and/or the oil jacket annulus) to the high temperature and low viscosity oil under atmospheric pressure is based on the injection amount of the low viscosity oil, the solubility of the gas in the low viscosity oil, the gas sweep range, and the sweep range.
  • the gas swept range is calculated according to the swept radius of the reservoir, the thickness of the oil layer and the porosity of the oil layer, and the swept radius of the oil reservoir is outside the produced oil reservoir.
  • the distance from the boundary to the oil well; the volume ratio of the injected gas to the low-viscosity oil under atmospheric pressure is preferably calculated according to the following formula:
  • IGOR is the volume ratio of injected gas to low-viscosity oil at atmospheric pressure
  • I o is the injection strength of low-viscosity oil, m 3 /m
  • D g is the solubility of injected gas in low-viscosity oil injected into the reservoir
  • R is Reservoir swept radius, m
  • ⁇ is the average porosity of the reservoir
  • S o is the oil saturation within the swept range of the reservoir
  • Sw is the water saturation within the swept range of the reservoir
  • S g is the swept range of the reservoir Gas saturation
  • ⁇ P is the increase in reservoir pressure, MPa
  • P 0 is atmospheric pressure, MPa.
  • the production method provided by the present invention is a method for injecting high-temperature and low-viscosity oil or a combination of high-temperature and low-viscosity oil and gas into a high-viscosity oil reservoir for huff and puff production.
  • the conditions and the composition of the injected low-viscosity oil determine the safe injection temperature and injection intensity. Below the safe injection temperature, control the appropriate injection intensity to inject the high-temperature low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas into the high-viscosity oil reservoir.
  • the high viscosity oil in the medium is dissolved and heated to reduce the viscosity, increase the formation pressure, and perform huff and puff production.
  • High-temperature low-viscosity oil is injected into a high-viscosity oil reservoir, which can improve the fluidity of the high-viscosity oil in the formation by dissolving, diluting and heating, and quickly recover it. Because the water quality treatment of boiler water is removed, the fuel consumption of heating and distilling crude oil is significantly lower than the fuel consumption of steam generated by the boiler, and the amount of produced water is greatly reduced. Therefore, the cost of producing high-viscosity oil by injecting low-viscosity oil into the formation with huff and puff will be obvious. It is lower than steam injection methods such as steam huff and puff.
  • the high-viscosity oil recovery method of the invention has the advantages of economy, high efficiency and energy saving, and the cost is obviously lower than that of steam injection recovery methods such as steam huff and puff, especially when high-viscosity oil is recovered by on-site distillation of low-viscosity oil fractions and huff and puff.
  • the high-viscosity oil recovery method of the present invention can be used for the recovery of high-viscosity oil reservoirs such as heavy oil and high-point-point oil, and is especially suitable for high-viscosity oil reservoirs with poor steam injection thermal recovery effect or high cost, and due to water sensitivity or water shortage, etc. The reason is high-viscosity oil reservoirs that cannot be injected with water or steam.
  • the high-viscosity oil production method of the present invention can produce high-viscosity oil production wells in vertical wells, directional inclined wells, horizontal wells, lateral wells, fishbone wells or other well types.
  • the scope of application of the high-viscosity oil recovery method of the present invention is not limited to the above-mentioned scope, and is applicable to all oil reservoirs that can be recovered by using the low-viscosity oil fractions provided by the present invention by on-site distillation.
  • the high-viscosity oil recovery method provided by the present invention utilizes the light components, intermediate components and heavy components obtained by extracting the high-viscosity oil distillation, and has low requirements on the cutting precision of the components, the distillation process is relatively simple, and the equipment and relatively low operating costs.
  • the high-viscosity oil recovery method provided by the present invention utilizes on-site distillation of low-viscosity oil fractions to huff and puff to exploit high-viscosity oil
  • the high-temperature and low-viscosity oil obtained by on-site distillation can be heat-exchanged by a settling tank and a dehydration desalination treatment tank , while heating the high-viscosity oil in the sedimentation tank and the dehydration and desalination treatment tank, the low-viscosity oil is cooled to a safe injection temperature, thereby simplifying the process and saving energy.
  • the high-temperature and low-viscosity oil obtained by the distillation of the high-viscosity oil is injected into the oil well or mixed with other media to produce high-viscosity oil by huff and puff.
  • Oil layer heating can improve the fluidity of high-viscosity oil in the formation, and can also improve formation pressure and oil displacement, thereby achieving the effect of improving oil well production and reservoir recovery.
  • the high-viscosity oil recovery method provided by the present invention is by injecting the high-temperature and low-viscosity oil obtained by extracting the high-viscosity oil distillation into the oil layer to carry out oil recovery, and comprehensively utilizes the dissolution, dilution and heating effects of the high-temperature and low-viscosity oil to improve the fluidity of crude oil, Compared with the high temperature steam injection method which mainly relies on heating, the energy consumption and cost are significantly reduced. At the same time, since the re-injection of high-temperature and low-viscosity oil utilizes the heat of distillation, the thermal efficiency is further improved and the cost is reduced.
  • the high-temperature and low-viscosity oil re-injected by the high-viscosity oil recovery method provided by the present invention can dissolve and dilute the formation high-viscosity oil, reduce the viscosity and weaken the temperature sensitivity, easy to lift and transport, and can eliminate or reduce the wellbore lift difficulty and cost.
  • the high-viscosity oil extraction method provided by the present invention can use the low-viscosity oil and/or residual oil obtained by high-temperature distillation as the fuel for technological processes such as distillation and power generation.
  • the high-viscosity oil recovery method provided by the present invention greatly reduces the amount of injected water and produced water, and reduces the difficulty and cost of surface water treatment.
  • the high-viscosity oil recovery method provided by the present invention can gradually dissolve and dilute the high-viscosity oil in the formation by injecting the high-temperature and low-viscosity oil obtained by distillation back into the oil layer, and can convert heavy oil reservoirs and high-point pour oil reservoirs into "thin oil". Oil” reservoirs greatly reduce the difficulty of exploitation, and further, they can be converted into conventional exploitation methods such as water injection and polymer injection for exploitation.
  • the high-viscosity oil recovery method provided by the present invention comprehensively utilizes the dissolution dilution and heating effects of re-injection of high-temperature and low-viscosity oil, and can be mixed with other media for oil recovery, and is suitable for a wide range of oil reservoirs. It is suitable for heavy oil reservoirs and high pour point oil reservoirs, especially for high viscosity oil reservoirs with poor thermal recovery effect or high cost of steam injection, and oil reservoirs where water or steam injection cannot be performed due to water sensitivity or water shortage.
  • Fig. 1 is a schematic diagram of the method for producing high-viscosity oil by huff and puff of distilled low-viscosity oil fraction according to Example 1.1, the specific meanings of the symbols in the figure are: 1: oil layer, 2: overlying rock layer, 3: oil well, 4: high-viscosity oil pipeline, 5: Pump, 6: Settling tank, 7: Dehydration and desalination treatment tank, 8: Brine pipeline, 9: High-viscosity oil pipeline after dehydration and desalination, 10: Atmospheric pressure heating furnace, 11: Atmospheric pressure tower; 12: Light fraction Pipeline, 13: heavy distillate pipeline, 14: vacuum heating furnace, 15: vacuum tower, 16: middle distillate pipeline, 17: vacuum residue pipeline, 18: high temperature and low viscosity oil pipeline, 19: low viscosity after cooling down Oil pipeline, 20: buffer tank, 21: high viscosity oil production well, 22: other medium pipeline, 23: gas action area, 24: low viscos
  • Fig. 2 is the flow chart of the ignition simulation experiment device in the method for producing high-viscosity oil by huff and puff of distilled low-viscosity oil fraction according to Example 1.1, the specific meanings of the symbols in the figure: 2011: the first injection pump, 2012: the second injection pump, 2021: First Intermediate Vessel, 2022: Second Intermediate Vessel, 2031: First Valve, 2032: Second Valve, 204: Collection Valve, 205: High Temperature Box, 206: Heating Coil, 207: Back Pressure Valve, 208: Visual combustion kettle, 209: flame combustion chamber, 210: window, 211: pressure gauge; 212: air cylinder, 213: oxygen cylinder, 214: nitrogen cylinder, 215: low-viscosity oil collection container;
  • Fig. 3 is a thick layer super-heavy oil reservoir model diagram of deploying horizontal wells by utilizing distilled low-viscosity oil fraction huff and puff production according to Example 2.1;
  • Fig. 4 is the viscosity distribution diagram of oil reservoir crude oil at the end of 10 cycles of injection using distillation low-viscosity oil fraction + carbon dioxide huff and puff according to Example 2.1;
  • Fig. 5 is the single well daily oil production and daily water production dynamic curve predicted by numerical simulation of the middle-deep thick layer ordinary heavy oil reservoir in which the horizontal well is exploited by utilizing distilled low-viscosity oil fraction and nitrogen huff and puff according to embodiment 2.2;
  • Fig. 6 is the single well day predicted by the numerical simulation of the medium-deep thick ordinary heavy oil reservoir in which the horizontal well is deployed in order to compare the steam huff and puff (injection and production period of 8 months) of the distilled low-viscosity oil fraction and nitrogen huff and puff (injection and production period of 8 months) of Example 2.2 Oil production and daily water production dynamic curves;
  • Fig. 7 is a model structure diagram of a thick-layer super-heavy oil reservoir deploying vertical wells by utilizing distilled low-viscosity oil fraction huff and puff production according to Example 3.2;
  • Fig. 8 is the model diagram of utilizing distillation low-viscosity oil fraction huff and puff to exploit thick layer edge bottom water common heavy oil reservoir according to embodiment 4.1;
  • Fig. 9 is the sectional view of utilizing distillation low-viscosity oil fraction huff and puff to exploit common heavy oil reservoir with thick edge and bottom water according to embodiment 4.1;
  • Fig. 10 is the model diagram of utilizing distillation low-viscosity oil fraction huff and puff to exploit thin-layer edge-bottom water common heavy oil reservoir according to Example 4.2;
  • Fig. 11 is a cross-sectional view of a common heavy oil reservoir with thin edge and bottom water produced by huff and puff of distilled low-viscosity oil fraction according to Example 4.2.
  • the low-viscosity oil is obtained by in-situ distillation and the safe injection temperature of the low-viscosity oil is determined by adopting the method of huffing and puffing low-viscosity oil fractions by on-site distillation.
  • oil well 3 passes through overlying rock layer 2 into oil layer 1, and the high-viscosity oil produced by oil well 3 is injected into sedimentation tank 6 through high-viscosity oil pipeline 4 through pump 5 for a dehydration and desanding treatment; And the high-viscosity oil after the desanding treatment is injected into the dehydration and desalination treatment tank 7 through a pump for deep dehydration and desalination treatment, the high-viscosity oil is dehydrated to less than 5%, and the brine produced by the dehydration and desalination treatment tank 7 is discharged through the brine pipeline 8; The high-viscosity oil after dehydration and desalination is injected into the atmospheric pressure heating furnace 10 after the high-viscosity oil is dehydrated and desalted by the pump, and the high-viscosity oil is heated to 350°C-360°C and then enters the atmospheric distillation tower 11 for atmospheric distillation.
  • Light distillate and heavy distillate wherein the light distillate enters the high temperature and low viscosity oil pipeline 18 through the light distillate line 12 and then enters the dehydration and desalting treatment tank 7 for heat exchange, and the heavy distillate passes through the heavy distillate 13.
  • Pressure heating furnace 14 heat the high viscosity oil to 350°C-370°C and then enter vacuum tower 15 for vacuum distillation to obtain middle distillate and vacuum residue, and finally obtain three kinds of light distillate, middle distillate and heavy residue Distillate, wherein, the middle distillate enters the high temperature and low viscosity oil pipeline 18 through the middle distillate pipeline 16 and then enters the dehydration and desalination treatment tank 7 for heat exchange, and the heavy residual oil passes through the vacuum residual oil pipeline 17 after heat exchange and is exported or used as on-site distillation.
  • Fuels such as heating, light distillate, middle distillate or a mixture of the two in a certain proportion can be used as a high-temperature and low-viscosity oil to inject into the oil well through the high-temperature and low-viscosity oil pipeline 18, and pass through the dehydration and desalination treatment tank 7 and the internal heat exchange of the settling tank 6. After cooling down, the low-viscosity oil pipeline 19 enters the buffer tank 20.
  • the low-viscosity oil in the buffer tank 20 can be injected into the high-viscosity oil production well 21 through a pump, and the high-temperature and low-viscosity oil forms a low-viscosity oil action area 24 injected into the formation.
  • gas such as nitrogen gas or other medium can be injected into the high-viscosity oil production well 21 through other medium pipelines 22 to form a gas action area 23 to assist the high-temperature and low-viscosity oil extraction underground high-viscosity oil.
  • the safe injection temperature of low-viscosity oil is a key parameter for the invention to utilize the distillation of low-viscosity oil fractions to huff and puff to exploit high-viscosity oil.
  • a high-viscosity oil from a certain oilfield is used to simulate 350°C atmospheric distillation and vacuum distillation experiments to obtain light fractions. and middle distillate, and according to the methods recorded in ASTMD-2892/92 and ASTMD-5236-92 in "Crude Oil Evaluation Method" (1994 edition), the light distillate and middle distillate were subjected to conventional distillation experiments respectively, and obtained different boiling point ranges. Distillate content, the results are shown in Table 1.
  • the ignition temperatures of the light fraction and middle fraction obtained by distillation under atmospheric pressure can be estimated to be 291°C and 201°C, respectively, and the light fraction and middle fraction are 1:1.
  • Ignition temperature at atmospheric pressure was estimated to be 246°C when proportionally mixed.
  • the ignition simulation experiment of this embodiment is carried out by using the ignition simulation experiment device shown in FIG. 2 .
  • the ignition simulation experiment device at least includes: a first injection pump 2011 , a first intermediate container 2021 , a first valve 2031 , a second injection pump 2012 , The second intermediate container 2022, the second valve 2032, the collection valve 204, the high temperature box 205, the heating coil 206, the back pressure valve 207, the visual combustion kettle 208 (with the flame combustion chamber 209, the window 210), the pressure gauge 211, Air cylinder 202, oxygen cylinder 213, nitrogen cylinder 214, and low-viscosity oil collection container 215; wherein, the first injection pump 2011 is connected to the bottom of the first intermediate container 2021 through a pipeline, and the upper outlet of the first intermediate container 2021 passes through The pipeline (with the first valve 2031) is connected to the inlet of the heating coil 206 in the high temperature box 205, the second injection pump 2021 is connected to the bottom of the second intermediate container 2022 through the pipeline, and
  • the above-mentioned ignition simulation experimental device is used to test the ignition temperature of light fraction, middle fraction, low-viscosity oil (a mixture of light fraction and middle fraction in a ratio of 1:1) and their mixture with nitrogen.
  • the pressure of the back pressure valve 207 is controlled at 10MPa, and the pressure in the combustion kettle 208 can be seen as atmospheric pressure, and the gas is air.
  • the light fraction ignition test temperature ie the temperature of the high temperature box
  • the ignition test temperature of middle distillate was set to 191 °C, 201 °C and 211 °C, respectively, and the ignition test temperature of low-viscosity oil was set to 236 °C, 246 °C and 256 °C, respectively.
  • the ignition condition of the high temperature and low viscosity oil at the outlet of the pipeline is observed through the window 210 of the visual combustion kettle 208 .
  • the lowest ignition temperature of the middle distillate was measured to be 194 °C, and the minimum ignition temperature of the mixture of light distillate and middle distillate in a ratio of 1:1 was 230 °C.
  • Table 2 The results of the ignition simulation experiment of light fractions obtained by simulated distillation of high-viscosity oil in an oilfield
  • the minimum ignition temperature of low-viscosity oil can be increased by injecting inert gas such as nitrogen while injecting low-viscosity oil.
  • inert gas such as nitrogen
  • the minimum ignition temperatures measured by the ignition simulation experiment method were 282°C, 337°C, 396°C and 471°C, respectively.
  • a thick super-heavy oil reservoir in which horizontal wells are deployed is exploited by huff and puff of in-situ distillation of low-viscosity oil fractions.
  • the in-situ distillation process similar to Example 1.1 is used to obtain injectable low-viscosity oil, and the light components and intermediate components obtained by distillation are mixed to obtain 50°C viscosity of 150 mPa ⁇ s, 75 mPa ⁇ s and 37.5 mPa ⁇ s, respectively. mPa ⁇ s low viscosity oil.
  • a 600m ⁇ 600m ⁇ 30m horizontal, homogeneous, thick-layered heavy oil reservoir with a top depth of 1000m and a thickness of 30m has three horizontal wells deployed in parallel. It is deployed at a position of 3.5m from the bottom of the oil layer.
  • the specific reservoir parameters are shown in Table 3.
  • a homogeneous oil reservoir geological model with 60 ⁇ 30 ⁇ 30 grids was established. The grid size in the X direction is 5m, the grid size in the Y direction is 20m, and the grid size in the Z direction is 1m.
  • the injection strength of the low-viscosity oil and the low-viscosity oil in the first cycle can be obtained.
  • the maximum injection strengths are 8.8m 3 /m and 13.6m 3 /m, respectively, and the volume ratio of injected nitrogen to low-viscosity oil (referred to as gas-oil ratio for short) is 101.
  • the calculation process is as follows:
  • the injection strength of low viscosity oil in the first cycle is:
  • the maximum low viscosity oil injection strength is:
  • the injection medium includes high temperature and low viscosity oil (the viscosity of high temperature and low viscosity oil at 50°C is 150mPa ⁇ s, 75mPa ⁇ s and 37.5mPa ⁇ s), high temperature and low viscosity oil + nitrogen, high temperature and low viscosity oil + carbon dioxide, and the injection medium temperature is 270 °C (In this example, when the volume ratio of injected gas and low-viscosity oil under atmospheric pressure is 50-100, the minimum ignition temperature is 350-400°C. In order to ensure the safety of injection, the actual maximum injection temperature of low-viscosity oil on site is 300°C.
  • the temperature of the low-viscosity oil at the bottom of the well is about 270°C after considering the heat loss of the wellbore), and the daily oil injection rate is 300m 3 /d.
  • the injection volume of low-viscosity oil in the first three cycles is 3500m 3 , 4000m 3 and 4500m 3 respectively, and the injection volume of low-viscosity oil in the last seven cycles is 5000m 3 . Two cases of reducing the implant by 20% and increasing it by 20% were considered.
  • the volume ratio of injected gas and low-viscosity oil at atmospheric pressure was determined to be 100.
  • the soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • the steam injection temperature is 344°C; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the steam injection volume of the first three cycles is For 3000m 3 , 4500m 3 and 6000m 3 , the periodic steam injection volume of the last seven cycles is 7500m 3 .
  • the soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • the STARS thermal recovery simulator of CMG company was used to carry out the reservoir numerical simulation. It can be seen that the cumulative oil recovery (net oil recovery after low-viscosity oil injection is removed) for 10 cycles of huff and puff with low viscosity oil injected at 270°C and 150 mPa ⁇ s is 73.3% of that of steam huff and puff, but the produced water is only 6.2% of steam huff and puff. %.
  • the cumulative oil recovery of low-viscosity oil injected at 270°C and 150mPa ⁇ s + nitrogen (gas-oil ratio 100) or carbon dioxide huff and puff (gas-oil ratio 100) is close to that of steam huff and puff, reaching 93.1% and 99.5% of steam huff and puff, respectively.
  • the volume ratio of injected gas to low-viscosity oil was increased to 200, the cumulative oil recovery by injecting low-viscosity oil and carbon dioxide at 270 °C, 150 mPa ⁇ s and carbon dioxide increased significantly, reaching 1.17 times that of steam huff and puff.
  • the oil recovery effect can reach or exceed the conventional steam huff and puff, and no water injection or steam is required, and the cumulative water production in 10 cycles of production is only 10% of the steam huff and puff. 6.2%-14.1%, and the water treatment process of the ground boiler is eliminated, and the dehydration treatment capacity is greatly reduced.
  • the cost of injecting nitrogen or carbon dioxide and the amount of low-viscosity oil injected is only 71% of the steam injection amount of steam stimulation, it is estimated that the cost of producing super-heavy oil by utilizing on-site distillation of low-viscosity oil fractions in the present invention can be reduced to steam. Throughput about 1/2.
  • the cumulative oil recovery of 10 cycles of production has all The reason for the decrease is that the swept range will be reduced when the injection is low, while the recovery of low-viscosity oil will take too long when the injection is high, and the formation temperature will decrease, which will affect the periodic production effect. Therefore, a reasonable injection strength of low-viscosity oil needs to be adopted when adopting the on-site in-situ distillation high-temperature low-viscosity oil huff and puff production process of the present invention. At the same time, it shows that the low-viscosity oil injection strength design method provided by the present invention is reliable.
  • Figure 4 shows the oil viscosity distribution profile of the reservoir at the end of 10 cycles of low-viscosity oil injected at 270 °C and 150 mPa ⁇ s + CO2 huff and puff (gas-oil ratio 100). It can be seen that due to the action of injected high temperature and low viscosity oil and CO 2 , the viscosity of crude oil within 20m near the wellbore is reduced to 1500mPa ⁇ s, while the viscosity of crude oil within 10m near the wellbore can be as low as below 200mPa ⁇ s.
  • the viscosity of the produced oil gradually increases during the cycle of high temperature and low viscosity oil (150 mPa ⁇ s) + carbon dioxide huff and puff (gas-oil ratio 100), and the viscosity of the produced oil gradually decreases when the huff and puff cycle increases.
  • the viscosity of the produced oil was the highest, and the viscosity of the produced oil at the bottom hole was 3800 mPa ⁇ s.
  • the bottom-hole viscosity of the produced oil is only about 200 mPa ⁇ s.
  • the viscosity of the produced oil is greatly reduced when the low-viscosity oil or the combination of low-viscosity oil and gas is used for huff and puff production of super-heavy oil, and even wellbore dilution and heat tracing can be eliminated.
  • the viscosity of the low-viscosity oil obtained by distillation after the ultra-heavy oil is diluted by injection into the low-viscosity oil gradually decreases, and the production increase effect will gradually increase.
  • the high-temperature low-viscosity oil Or it can be combined with nitrogen/carbon dioxide injection into super heavy oil reservoirs for huff and puff production.
  • the viscosity of heavy oil within 20m near the well can be significantly reduced, and the production of oil wells can be significantly improved, which can reach or exceed conventional steam.
  • the effect of super-heavy oil recovery can be improved by increasing the gas-oil ratio of huff and puff injection gas and low-viscosity oil, increasing the temperature, optimizing the composition and injection strength of low-viscosity oil.
  • the injection temperature of low-viscosity oil is low, in order to ensure the recovery effect, the content of light components in the low-viscosity oil produced by distillation should be increased, and the viscosity of the injected low-viscosity oil should be reduced.
  • the bottom hole temperature and crude oil viscosity during different periods of injection of 150°C, 37.5mPa ⁇ s (50°C) high-temperature and low-viscosity oil + CO 2 huff and puff for ultra-heavy oil production are shown in Table 5.
  • the mining time increases gradually and gradually decreases with the increase of the throughput period.
  • the super-heavy oil with the formation viscosity of 52800mPa ⁇ s after hot oil+CO 2 huff and puff reduces the crude oil viscosity to 4821.7-107.4mPa ⁇ s at the end of the cycle (the viscosity level of ordinary heavy oil).
  • the viscosity of produced oil can be reduced to below 1000-2000 mPa ⁇ s, which can eliminate the dilution and heat tracing process during wellbore lifting and reduce the cost of oil production.
  • the viscosity of the injected low-viscosity oil can be 5mPa ⁇ s-500mPa ⁇ s when the low-viscosity oil fraction is recovered by huff and puff of the present invention. (50°C), the injection temperature can be 100°C-300°C. Since the viscosity of super heavy oil is sensitive to temperature, the injection temperature should be increased as much as possible in the first few cycles of huff and puff production. Lower the injection temperature.
  • the injection strength of low-viscosity oil can be 10m 3 /m oil layer-15m 3 /m oil layer, which can be determined by calculation with reference to the method provided by the present invention.
  • the injected gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases.
  • the volume ratio of the amount to the injection amount of low-viscosity oil is 50-100 at atmospheric pressure, and the injection method can be mixed injection or subsequent slug injection.
  • the injection period can be 3-12 months.
  • the soaking time after injection of low viscosity oil and gas can be 1-10 days.
  • the present embodiment utilizes in-situ in-situ distillation of low-viscosity oil fractions to huff and puff out a thick-layer common heavy oil reservoir where horizontal wells are deployed.
  • Example 1.1 the in-situ distillation process similar to Example 1.1 was used to obtain injectable low-viscosity oil, and three types of low-viscosity oils were obtained by mixing in different proportions. 75mPa ⁇ s and 100mPa ⁇ s.
  • the developed reservoir model is the same as that in Example 2.1, except that the heavy oil is ordinary heavy oil, and the viscosity of the heavy oil is 1500 mPa ⁇ s (the viscosity of degassed oil is 5260 mPa ⁇ s) under formation conditions.
  • the injection of high temperature and low viscosity oil + nitrogen huff and puff is used for 10 cycles, the injection and production cycle is 1 year, and the total production is 10 years.
  • the injection temperature of low-viscosity oil was 50°C, 150°C, 180°C, and 200°C, respectively, and the viscosity of injected low-viscosity oil at 50°C was 37.5 mPa ⁇ s and 75 mPa ⁇ s, respectively.
  • the reasonable periodic low-viscosity oil injection strength determined with reference to the design method provided by the present invention is 6.2-8.3 m 3 /m, and the volume ratio of injected gas to low-viscosity oil under atmospheric pressure is 68.7.
  • the injection volume of low-viscosity oil is 2000m 3 -3000m 3
  • the volume ratio of injected nitrogen to low-viscosity oil under atmospheric pressure is 66.7 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the distillation unit meets the low
  • the daily injection volume of viscous oil is 300m 3 ), and the well is kept for 5 days, and the production flow pressure is 2.5MPa.
  • the steam injection temperature is 344°C; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the steam injection volume of the first three cycles is For 3000m 3 , 4500m 3 and 6000m 3 , the steam injection volume of the last 7 cycles is 7500m 3 , the soaking time is 4 days, the maximum daily fluid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • CMG's STARS thermal recovery simulator was used for reservoir numerical simulation.
  • the calculation results of single-well injection and production parameters calculated by different methods of huff and puff production in thick layer ordinary heavy oil reservoirs for 10 years are shown in Table 6.
  • the injection of low viscosity oil and nitrogen huff and puff The dynamic curves of daily oil production and daily water production of a single well (injection and production period of 8 months) are shown in Figure 5, and the dynamic curves of daily oil production and daily water production of a single well with steam huff and puff (injection and production period of 8 months) are shown in Figure 6.
  • the cumulative oil production of 10 cycles of high temperature and low viscosity oil + nitrogen huff and puff production at 150°C and viscosity of 37.5mPa ⁇ s, 75mPa ⁇ s and 100mPa ⁇ s (50°C), respectively is 105479m 3 and 101783m 3 , respectively. and 98201m 3 , which are 1.24, 1.2 and 1.15 times of the steam huff and puff respectively, and have achieved a significant increase in production.
  • the water production is only less than 1/5 of the steam huff and puff. Therefore, when the low-viscosity oil fraction is distilled in-situ by the method of the present invention, the high-temperature and low-viscosity oil is injected with low energy consumption, low water production and low cost during huff and puff production.
  • the cumulative oil production of 10 cycles of huff and puff production by injecting low-viscosity oil with a viscosity of 37.5 mPa ⁇ s at 50°C and temperatures of 50°C, 150°C, 180°C and 200°C and nitrogen gas for 10 cycles is 99125m 3 , 105479m 3 , 106595m 3 and 107283m 3 , respectively 1.16, 1.24, 1.25 and 1.26 times the steam huff and puff. It can be seen that, for ordinary heavy oil with lower viscosity, the injection of low-viscosity oil with lower temperature and nitrogen can achieve obvious production increase effect.
  • the injection strength of the oil can be 5-10m 3 /m, and the periodic low-viscosity oil injection volume is 2000m 3 -4000m 3 .
  • the injected gas can be nitrogen, carbon dioxide, natural gas, flue gas, etc., and the volume ratio of the gas injection amount to the low-viscosity oil injection amount under atmospheric pressure can be 50-100.
  • This embodiment utilizes on-site in-situ distillation of low-viscosity oil fraction huff and puff to exploit thick super-heavy oil reservoirs in which horizontal wells are deployed in the middle and late stages of steam huff and puff.
  • Example 1.1 an in-situ distillation process similar to that of Example 1.1 was used to obtain an injectable low-viscosity oil, and the viscosity at 50° C. was 37.5 mPa ⁇ s.
  • the reservoir model and well deployment are the same as in Example 2.1. After 10 cycles and 20 cycles of steam huff and puff, respectively, 10 cycles of high temperature and low viscosity oil + nitrogen huff and puff were carried out.
  • the working system during oil production was the same as in Example 2.1.
  • the injection-production cycle of each cycle of steam huff and puff is 0.5 years, the steam injection temperature is 344°C, and the steam injection dryness is 0.3; the steam injection rate in the first cycle is 200m 3 /d, and the steam injection rate in the second and subsequent cycles is 300m. 3 /d; the steam injection volume of the first 3 cycles is 3000m 3 , 4500m 3 and 6000m 3 in turn, and the cycle steam injection volume of the last 7 cycles is 7500m 3 .
  • the soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • the low-viscosity oil fraction of the present invention is used for huff and puff production.
  • nitrogen is injected at the same time as the low-viscosity oil fraction is injected, and 10 cycles of huff and puff are carried out.
  • the injection-production cycle of each cycle is 0.5 years, a total of 5 years of mining.
  • the viscosity of the injected low-viscosity oil is 37.5 mPa ⁇ s (50°C), and the temperature of the injected low-viscosity oil is 150°C-300°C.
  • the reasonable injection strength of low-viscosity oil transfer injection can be obtained as 8.8m 3 /m-13.6m 3 /m, and the volume ratio of injected nitrogen to low-viscosity oil is 101 According to this, the oil injection volume of the first two cycles is 3000m 3 and 4000m 3 respectively, and the oil injection volume of the last eight cycles is 5000m 3 .
  • the volume ratio of injected nitrogen and low-viscosity oil at atmospheric pressure is 90 (considering that the daily injection volume of the ordinary nitrogen injection equipment on site is 20,000m 3 , and the daily injection volume of the low-viscosity oil for the distillation unit is 300m 3 , the injection is performed during the low-viscosity oil injection stage.
  • the volume ratio of nitrogen to low-viscosity oil is 66.7, but after stopping the injection of low-viscosity oil, nitrogen is continuously injected, and finally the volume ratio of nitrogen to low-viscosity oil is 90).
  • the daily oil injection rate is 300m 3 /d, and the soaking time is 5 days. During oil production, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • the cumulative oil recovery of 10 cycles is 47858.3 m 3 , which is 93.1% of the cumulative oil recovery of the next 10 cycles of steam huff and puff.
  • the cumulative oil recovery of high temperature and low viscosity oil + N 2 huff and puff for 10 cycles is 53728.3m 3 , which is 1.05 times of the cumulative oil recovery of steam huff and puff in the next 10 cycles.
  • the cumulative oil recovery of 150°C high temperature and low viscosity oil + N2 huff and puff for 10 cycles is equivalent to that of 30 cycles of steam huff and puff.
  • the viscosity of the injected low-viscosity oil can be 5 mPa ⁇ s when the low-viscosity oil fraction is huff and puff produced by in-situ distillation of the present invention.
  • the injection temperature can be 100°C-300°C
  • the injection strength of low-viscosity oil can be 5m 3 /m oil layer to 15m 3 /m oil layer, which can be determined by calculation with reference to the method provided in the present invention
  • the injection gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases.
  • the volume ratio of gas injection to low-viscosity oil injection under atmospheric pressure is 50-100.
  • the injection method can be mixed injection or subsequent slug injection.
  • the injection period can be 8-16 months.
  • the soaking time after injection of low viscosity oil and gas can be 1-10 days.
  • the low-viscosity oil fraction huff and puff of the present invention can achieve the effect equivalent to that of steam huff and puff by on-site distillation, and can be further improved by reducing the viscosity of the injected low-viscosity oil, increasing the injection temperature of the low-viscosity oil, properly increasing the gas-oil ratio and optimizing the injection amount Yield increase effect.
  • steam huff and puff it has obvious advantages of low energy consumption, low produced water volume and low cost.
  • the super-heavy oil reservoir in which the vertical well is deployed in the later stage is exploited by utilizing the on-site in-situ distillation of low-viscosity oil fraction huff and puff to exploit the steam huff and puff of the present invention.
  • Example 1.1 an in-situ distillation process similar to that of Example 1.1 was used to obtain an injectable low-viscosity oil, and the viscosity at 50° C. was 35 mPa ⁇ s.
  • an ultra-heavy oil reservoir with a depth of 600m and an area of 200m ⁇ 200m has three oil layers, each of which is 5m thick, with a total thickness of 15m.
  • the thickness of the upper and lower layers is 4m and 3m respectively.
  • the top-to-bottom porosity of the three oil layers is 0.33, 0.315 and 0.34, and the permeability is 3000mD, 2000mD and 4000mD, respectively.
  • the viscosity of heavy oil is 121088mPa ⁇ s
  • the viscosity of degassed oil at 45°C is 212903mPa ⁇ s.
  • the original oil layer temperature is 45°C
  • the original oil layer pressure is 6MPa
  • the original oil saturation is 0.675.
  • the numerical simulation reservoir model has a total of 40 ⁇ 40 ⁇ 20 grids, the size of the grid in the X and Y directions is 5m, and the size of the grid in the Z direction is 1m-2m.
  • in-situ distillation of low-viscosity oil fraction huff and puff is used to exploit the super-heavy oil reservoir in which vertical wells are deployed in the later stage of steam huff and puff.
  • the steam huff and puff is exploited for 10 cycles, and the injection-production cycle of each cycle is 0.5 years, for a total of 5 years of exploitation.
  • the steam injection rate of the first cycle of a single well is 200m 3 /d
  • the steam injection rate of the subsequent cycles is 300m 3 /d.
  • the cyclical steam injection volume for 5 cycles of a single well is 1000m 3 , 1500m 3 , 1800m 3 , 2400m 3 and 3000m 3 respectively.
  • the steam injection temperature was 344°C
  • the steam injection dryness was 0.3
  • the well soaking time was 3 days.
  • the maximum daily liquid production of a single well was 50m 3 /d
  • the minimum flow pressure was 0.5MPa.
  • 10 cycles of low-viscosity oil injection and nitrogen huff and puff were carried out, and the injection and production cycle of each cycle was 0.5 years, for a total of 5 years of production.
  • the injected low-viscosity oil has a viscosity of 35 mPa ⁇ s at 50°C, an injection temperature of 150°C, and a daily oil injection rate of 200m 3 /d-300m 3 /d for a single well.
  • the reasonable injection strength of low-viscosity oil injection is 71m 3 /m-118m 3 /m, and the volume ratio of injected nitrogen gas to low-viscosity oil is 108.
  • the designed single-well cycle low-viscosity oil injection volume is 1000m 3 -1800m 3 .
  • the soaking time is 3 days.
  • the maximum daily liquid production of a single well is 50 m 3 /d and the minimum flow pressure is 0.5 MPa during oil production. In order to compare the effect, 20 cycles of steam huff and puff were also carried out.
  • the first 10 cycles were the same as the above steam huff and puff, and the last 10 cycles were all injection-production cycles of 0.5 years.
  • the well steam injection rate is 300m 3 /d
  • the single well cycle steam injection volume is 3000m 3
  • the well soaking time is 3 days
  • the maximum daily liquid production of the oil well is 50m 3 /d
  • the minimum flow pressure is 0.5MPa.
  • the cumulative oil recovery after 5 cycles of huff and puff after the injection of low-viscosity oil is 1.08 times that of the steam huff and puff, and the water produced by the latter 5 cycles of huff and puff is only 14% of that of the steam huff and puff.
  • the low-viscosity oil injected by the on-site in-situ distillation low-viscosity oil fraction huff and puff method of the present invention is much lower than the steam injection amount of the steam huff and puff, and the combustion consumption of heating the low-viscosity oil is much lower than that of the high-temperature steam. In the process of boiler water treatment, the amount of produced liquid dehydration is also greatly reduced.
  • the viscosity of the injected low-viscosity oil can be 5 mPa ⁇ s- 500mPa ⁇ s (50°C)
  • injection temperature can be 100°C-300°C
  • injection intensity can be 50m 3 /m oil layer-150m 3 /m oil layer
  • injection gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases
  • the volume ratio of gas injection and low-viscosity oil injection under atmospheric pressure is 30-120 (the amount of injected gas can be reduced when steam channeling between wells is obvious in the middle and late stages of steam huff and puff)
  • the injection method can be mixed injection, front slug Or for subsequent slugs
  • the injection-production cycle can be 3-12 months.
  • the soaking time after injection of low viscosity oil and gas can be 1-10 days.
  • This embodiment utilizes on-site in-situ distillation of low-viscosity oil fraction huff and puff to exploit the thick-layer edge-bottom water common heavy oil reservoir with horizontal wells.
  • Example 1.1 an in-situ distillation process similar to that of Example 1.1 was used to obtain an injectable low-viscosity oil, and the viscosity at 50° C. was 37.5 mPa ⁇ s.
  • the developed reservoir model is an anticline structural edge-bottom water reservoir, the structure of the reservoir model is shown in Figure 8, and the section of the reservoir model is shown in Figure 9.
  • the depth of the oil layer is 1550m
  • the heavy oil is ordinary heavy oil
  • the viscosity of the heavy oil is 4500mPa ⁇ s under formation conditions (the viscosity of the degassed oil is 6370mPa ⁇ s at 50°C);
  • the oil layer thickness is 30m, the oil layer porosity is 0.3, and the permeability is 1500mD;
  • the volume ratio of reservoir edge and bottom water to oil area volume is 50; a total of 3 horizontal wells are deployed in parallel, with a horizontal well length of 300m and a well spacing of 100m. Oil wells far from the edge and bottom water are deployed at a distance of 13.5m from the bottom.
  • the reasonable injection strength of low-viscosity oil transfer injection can be obtained as 8.7m 3 /m-12.4m 3 /m, and the volume ratio of injected nitrogen to low-viscosity oil is 76, According to this, the injection volume of low-viscosity oil in the design cycle is 3000m 3 , and the volume ratio of injected nitrogen gas to low-viscosity oil is 66.7 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the daily injection volume of low-viscosity oil for the distillation unit is 300m 3 ), soaking the well for 5 days, and the production flow pressure is 2.5MPa.
  • the steam injection temperature of steam huff and puff is 344°C; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the cycle steam injection volume of each cycle According to 3000m 3 , 4500m 3 , 6000m 3 and 7500m 3 , after increasing to 7500m 3 , it will not increase.
  • the soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • the STARS thermal recovery simulator of CMG company is used to simulate the reservoir numerically.
  • the calculation results of injection and production parameters of each well calculated by different methods of huff and puff production for 10 years in the thick-layer edge-bottom water ordinary heavy oil reservoir are shown in Table 9. It can be seen that under the same injection-production parameters, the first-line wells, the second-line wells and the third-line wells whose distances from the edge and bottom water become farther in turn have great differences in the production effect due to the influence of water intrusion.
  • the cumulative oil production of high temperature and low viscosity oil with a viscosity of 37.5 mPa ⁇ s (50 °C) at 150 °C and nitrogen huff and puff production is comparable to that of steam huff and puff.
  • the cumulative water production of wells and third-line wells is significantly lower than that of steam huff and puff due to no steam injection, and the heat consumption and cost are also significantly lower than those of steam huff and puff.
  • the first-line well is close to the water at the edge and bottom and is prone to water intrusion, it is suitable for low oil production rate. Since the Hesanxian well is not prone to water invasion, the oil production rate can be increased.
  • the production effect of injecting high temperature and low viscosity oil + nitrogen huff and puff for 1 year and 2 cycles is better than that of 1 year and 1 cycle.
  • the viscosity of the injected low-viscosity oil can be 5 mPa ⁇ s- 300mPa ⁇ s (50°C)
  • the injection temperature can be 100°C-300°C
  • the injection strength of low-viscosity oil can be 5m 3 /m oil layer-15m 3 /m oil layer, which can be determined by calculation with reference to the method provided in the present invention
  • the injected gas can be natural gas, nitrogen, carbon dioxide, flue gas, etc.
  • the volume ratio of gas injection to low-viscosity oil injection under atmospheric pressure is 50-100.
  • the injection method can be mixed injection or subsequent slug injection.
  • the injection period can be 8-16 months.
  • the soaking time after injection of low viscosity oil and gas can be 1-10 days.
  • Oil temperature reducing the viscosity of injected low-viscosity oil, optimizing injection-production parameters such as low-viscosity oil injection and nitrogen gas-oil ratio can achieve better production effect than steam huff and puff, and have the advantages of low energy consumption, low produced water volume and low cost .
  • the thin-layer edge-bottom water common heavy oil reservoir with horizontal wells is exploited by huff and puff of on-site distillation of low-viscosity oil fractions.
  • Example 1.1 the in-situ distillation process similar to Example 1.1 was used to obtain injectable low-viscosity oil, and two types of low-viscosity oils were obtained by mixing in different proportions.
  • the viscosity at 50°C was 37.5mPa ⁇ s and 100mPa, respectively. ⁇ s.
  • the structure of the reservoir model is shown in Figure 10, and the section of the reservoir model is shown in Figure 11.
  • the oil layer depth of the reservoir model is 1550m
  • the oil layer thickness is 10m
  • the porosity is 0.3
  • the permeability is 1500mD.
  • the water volume to oil zone volume ratio was 50.
  • a total of 3 parallel horizontal wells are deployed.
  • the length of the horizontal wells is 300m and the well spacing is 100m.
  • the oil wells close to the edge and bottom water are deployed at a distance of 7.5m from the bottom, and the middle oil wells are deployed at a distance of 5.5m from the bottom, away from the oil wells of the edge and bottom water. Deployed at 2.5m from the bottom.
  • the distance between the edge and bottom water is 200m from the nearest oil well.
  • the reasonable injection strength of low-viscosity oil transfer can be obtained as 9.4m 3 /m-10.6m 3 /m, and the volume ratio of injected nitrogen gas to low-viscosity oil is 72 , the injection volume of low-viscosity oil in the design cycle is 3000m 3 , and the volume ratio of injected nitrogen gas to injected low-viscosity oil is 66.7 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the distillation unit meets the daily injection volume of low-viscosity oil.
  • the injection volume was 300m 3 ), the well was simmered for 5 days, and the production flow pressure was 2.5MPa.
  • the steam injection temperature of steam huff and puff is 344°C; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the cycle steam injection volume of each cycle After increasing to 7500m 3 according to 3000m 3 , 4500m 3 , 6000m 3 and 7500m 3 , it will not increase.
  • the soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
  • Table 10 shows the calculation results of single-well injection-production parameters calculated by different methods of huff and puff production in ordinary heavy oil reservoirs with thin layer edge and bottom water for 10 years.
  • the cumulative oil production in 10 cycles of huff and puff is 93.5% of that of steam huff and puff, but the accumulated water volume is only 23.1% of that of steam huff and puff, and no water steam needs to be injected when low-viscosity oil + nitrogen huff and puff (in the case of steam huff and puff, it needs to be injected every cycle).
  • 3000m 3 -7500m 3 steam 3000m 3 -7500m 3 steam
  • the cost of nitrogen injection is significantly lower than that of steam injection. Therefore, in this example, 3000m 3 of 150°C, 100mPa s (50°C) low-viscosity oil + nitrogen huff and puff is injected per cycle. The effect is comparable to that of steam huff and puff and the cost is significantly lower than that of steam huff and puff.
  • the viscosity of the injected low-viscosity oil can be 5 mPa ⁇ s- 300mPa ⁇ s (50°C)
  • the injection temperature can be 100°C-300°C
  • the injection strength of low-viscosity oil can be 5m 3 /m oil layer-15m 3 /m oil layer, which can be determined by calculation with reference to the method provided in the present invention
  • the injected gas can be natural gas, nitrogen, carbon dioxide, flue gas, etc.
  • the volume ratio of gas injection to low-viscosity oil injection under atmospheric pressure is 50-100.
  • the injection method can be mixed injection or subsequent slug injection.
  • the injection period can be 8-16 months.
  • the soaking time after injection of low viscosity oil and gas can be 1-10 days.
  • the low-viscosity oil fraction huff-puff production and deployment of vertical wells are used in on-site in-situ distillation of low-viscosity oil fraction common heavy oil reservoirs.
  • the low-viscosity oil injected in this example is low-viscosity oil produced in the oil field, and has a viscosity of 70 mPa ⁇ s at 50°C. After being heated in a heating furnace, it is injected into an ordinary heavy oil reservoir with low oil saturation through a vertical well. Nitrogen is injected into the casing annulus for low-viscosity oil and nitrogen huff and puff.
  • the structure of the reservoir model is the same as in Example 3.2, as shown in Figure 7. The difference is that the reservoir depth is 1500m, the viscosity of heavy oil is 1065mPa ⁇ s under formation conditions, the viscosity of degassed oil is 8700mPa ⁇ s, the formation permeability is 2000mD, the original oil layer temperature is 60°C, the original oil layer pressure is 15MPa, and the original oil layer pressure is 15MPa. The oil saturation is 0.55 and the water saturation is 0.45.
  • Four vertical wells are deployed in the reservoir according to the square well pattern, the well spacing is 100m, and the oil layers are perforated.
  • the numerical simulation reservoir model has a total of 40 ⁇ 40 ⁇ 10 grids, the size of the grid in the X and Y directions is 5m, and the size of the grid in the Z direction is 1m.
  • low-viscosity oil and nitrogen huff and puff are injected for production and low-saturation ordinary heavy oil reservoirs with vertical wells are deployed.
  • the huff and puff cycle is 10 cycles, and the injection and production cycle of each cycle is 1 year. Mining for 10 years.
  • the injected low-viscosity oil had a viscosity of 70 mPa ⁇ s at 50°C, and an injection temperature of 150°C.
  • the reasonable injection strength of low-viscosity oil huff and puff can be obtained as 76.3m 3 /m-88.4m 3 /m, and the volume ratio of injected nitrogen to low-viscosity oil is 92.
  • the injection volume of low-viscosity oil in this design period is 1200m 3 , and the volume ratio of injected nitrogen gas to injected low-viscosity oil is 100 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the daily injection volume of low-viscosity oil in the distillation unit is satisfied is 300m 3 , the volume ratio of nitrogen to low-viscosity oil is 66.7 in the low-viscosity oil injection stage, but after the injection of low-viscosity oil is stopped, nitrogen is continuously injected, and finally the volume ratio of nitrogen to low-viscosity oil is 100).
  • the daily oil injection rate of a single well is 300m 3 /d, and the soaking time is 3 days.
  • the maximum daily liquid production of a single well is 50m 3 /d, and the minimum flow pressure is 0.5MPa.
  • the steam injection rate of the first cycle of a single well is 200m 3 /d, and the steam injection rate of the subsequent cycles is 300m 3 /d.
  • the cyclical steam injection volumes of the first 4 cycles of a single well are 1000m 3 , 1500m 3 , 1800m 3 and 2400m 3 respectively, and the latter 6 cycles are all 3000m 3 .
  • the steam injection temperature was 344°C
  • the dryness of steam injection was 0.2
  • the soaking time was 3 days.
  • the maximum daily liquid production of a single well was 50m 3 /d, and the minimum flow pressure was 0.5MPa.
  • the simulation of low-viscosity oil and nitrogen huff and puff after 5 cycles of steam huff and puff was also carried out.
  • the injection and production parameters of steam huff and puff in the first 5 cycles were the same as those of steam huff and puff.
  • the temperature is 150°C
  • the daily oil injection rate of a single well is 300m 3 /d
  • the periodical injection rate of low-viscosity oil in a single well is 1200m 3
  • the soaking time is 3 days
  • the maximum daily liquid production of a single well is 50m 3 /d during oil production.
  • the minimum flow pressure is 0.5MPa.
  • the cyclical water recovery of steam huff and puff and low-viscosity oil and nitrogen huff and puff is high, but the cumulative water production of low-viscosity oil and nitrogen huff and puff is only 70%-80% of that of steam huff and puff. If the cumulative oil recovery of low-viscosity oil and nitrogen huff and puff after 5 cycles of steam huff and puff is 1.08 times that of steam huff and puff, it shows that switching to low-viscosity oil and nitrogen huff and puff in the middle and late stage of steam huff and puff will achieve better recovery effect.
  • the viscosity of injected low-viscosity oil can be 5mPa ⁇ s-300mPa ⁇ s (50°C)
  • the injection temperature can be 100°C-300°C
  • the injection strength of low-viscosity oil can be 50m 3 /m oil layer-100m 3 /m oil layer, which can be determined by calculation with reference to the method provided by the present invention.
  • the injected gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases, and the volume ratio of the gas injection amount to the low-viscosity oil injection amount under atmospheric pressure is 30 -120, the injection mode may be mixed injection or subsequent slug injection.
  • the injection period can be 6-12 months.
  • the soaking time after injection of low viscosity oil and gas can be 1-10 days.

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Abstract

Disclosed is a high-viscosity oil exploitation method. The method is to inject high-temperature low-viscosity oil or a combination of high-temperature low-viscosity oil and gas into a high-viscosity oil reservoir for steam stimulation. The high-temperature low-viscosity oil or the combination of the high-temperature low-viscosity oil and gas reduces the viscosity of high-viscosity oil in the stratum by means of dissolution and heating, and increases the stratum pressure; the high-temperature low-viscosity oil comprises one or a combination of two or more of light fractions and intermediate fractions obtained by on-site distillation of the high-viscosity oil.

Description

一种高粘油的开采方法A kind of mining method of high viscosity oil 技术领域technical field
本发明涉及一种高粘油的开采方法，属于石油开采技术领域。The invention relates to a method for exploiting high-viscosity oil, belonging to the technical field of petroleum exploitation.
背景技术Background technique
粘度较高的稠油和高凝油一般是采用注蒸汽等热力方式进行开采，其中，注蒸汽开采方式包括蒸汽吞吐、蒸汽驱和蒸汽辅助重力泄油。注蒸汽时除了要进行注入水水质净化处理和产出液脱水之外，还要采用锅炉将净化后的水加热产生高温蒸汽。虽然注蒸汽开采稠油可获得显著的开采效果，但也存在很多问题：(1)注蒸汽开采主要是通过高温蒸汽来加热油层，能耗大、成本高且因产生大量二氧化碳和污水而对环境产生不利影响；(2)锅炉用水的水处理成本高，采出液脱水处理难度大(高含水和高产液量时问题尤为突出)；(3)由于注入水和地下水的水质复杂容易产生结垢、矿物溶蚀，也容易产生油水乳化；(4)容易产生蒸汽超覆和汽窜等复杂的开采问题；(5)高粘的稠油和高凝油在井筒举升过程中因为温度降低而流动性变差，需要采用井下掺稀油和井筒电加热等方法来保证井筒中稠油和高凝油的流动性。因此，现有蒸汽吞吐等注蒸汽开采方法中由于通过注入经过水质处理和加热的高温“水”蒸汽，而产生了能耗大、成本高和环境影响大等诸多问题，在低油价条件下稠油注蒸汽开发的经济效益也不理想，亟待研发稠油和高凝油低成本开采方法来替代注入高温“水”蒸汽开采方法。Heavy oil and high pour point oil with high viscosity are generally recovered by thermal methods such as steam injection. Among them, steam injection recovery methods include steam huff and puff, steam flooding and steam-assisted gravity drainage. When injecting steam, in addition to purifying the injected water and dehydrating the produced liquid, a boiler is also used to heat the purified water to generate high-temperature steam. Although steam injection to recover heavy oil can achieve remarkable recovery effect, there are still many problems: (1) Steam injection recovery mainly heats the oil layer through high-temperature steam, which consumes a lot of energy, has high cost, and is harmful to the environment due to the production of a large amount of carbon dioxide and sewage. (2) The water treatment cost of boiler water is high, and the dehydration treatment of produced liquid is difficult (the problem is particularly prominent when the water content and high liquid production volume are high); (3) Due to the complex water quality of the injected water and groundwater, scaling is likely to occur , mineral dissolution, and easy to produce oil-water emulsification; (4) It is easy to produce complex production problems such as steam overlay and steam channeling; (5) High viscosity heavy oil and high pour point oil flow due to temperature reduction during the wellbore lifting process. The fluidity of heavy oil and high pour point oil in the wellbore is guaranteed by methods such as downhole mixing with dilute oil and electric heating of the wellbore. Therefore, in the existing steam injection production methods such as steam huff and puff, many problems such as large energy consumption, high cost and large environmental impact are generated due to the injection of high-temperature "water" steam that has undergone water quality treatment and heating. The economic benefits of oil injection steam development are not ideal, and it is urgent to develop a low-cost recovery method for heavy oil and high pour point oil to replace the high-temperature "water" steam recovery method.
除了向油藏地层中注入高温蒸汽加热地层中稠油或高凝油使其粘度明显降低之外，通过掺入或溶解粘度较低的原油也可使稠油或高凝油的粘度明显降低，向井筒和地面管线中的稠油或高凝油中掺入稀油来降低原油粘度和提高原油流动性方面已经有了广泛的研究和应用，在掺稀油的同时通过加热、注入天然气和乳化降粘剂等可以提高井筒掺稀降粘和井筒举升采油的效果或者减少掺入的稀油用量(参考文献1-7)。关于水驱稀油井和稠油井采用热油解堵方法可解除近井地层有机伤害以及“劈水疏油”等作用而提高油井产量(参考文献8-10)。关于在注蒸汽热采过程中注入低粘油或溶剂等来辅助蒸汽吞吐开采也有研究和应用(参考文献11)。发明专利“一种稠油催化改质降粘采输一体化方法及其装置”(参考文献12)给出了一种稠油油藏开采的稠油催化改质降粘采输一体化方法。一方面通过蒸馏将轻质组分注入油井减少井筒举升时掺稀油的用量，另一方面，分离出的稠油经催化改质降粘能直接外输。其技术方案是：按照稀油与稠油的质量比0.4-1.0掺入井筒中，降低稠油粘度；再从井中采出掺稀稠油，经换热器升温，加热炉加热到350℃，进入蒸馏塔，收集350℃前馏分油经换热器降温，注入井筒对稠油掺稀循环使用；350℃后重馏分油用泵输送到加热炉升温至370℃-420℃，再用泵加入改质催化剂，一同输入反应塔；在反应塔内重馏分油在改质催化剂作用下，催化改质为低粘度稠油，改质稠油经换热后直接外输。该技术方案的实质是收集350℃前馏分油冷却至60℃后注入井筒内将从地层流出的稠油通过掺稀降粘，解决井筒中稠油向上举升流动过程中因为温度降低而使稠油粘度增加、流动性变差的问题，而没有提出向地层中注入轻质馏分将地层中高粘度的稠油采出。In addition to injecting high-temperature steam into the reservoir formation to heat the heavy oil or high pour point oil in the formation to significantly reduce its viscosity, the viscosity of heavy oil or high pour point oil can also be significantly reduced by mixing or dissolving crude oil with lower viscosity. There has been extensive research and application in adding thin oil to heavy oil or high pour point oil in wellbore and surface pipeline to reduce the viscosity of crude oil and improve the fluidity of crude oil. Viscosity reducers, etc. can improve the effect of wellbore viscosity reduction and wellbore lifting oil recovery or reduce the amount of thin oil blended (References 1-7). Regarding water-flooding thin oil wells and heavy oil wells, thermal oil plugging removal method can relieve the organic damage of near-well formation and the effects of "splitting water and oil repelling" to improve oil well production (References 8-10). There are also studies and applications about injecting low-viscosity oil or solvent in the process of steam injection thermal recovery to assist steam huff and puff production (Reference 11). The invention patent "A method and device for the integrated production and transportation of heavy oil catalytic upgrading and viscosity reduction" (Reference 12) provides an integrated method of heavy oil catalytic upgrading, viscosity reduction, production and transportation for the recovery of heavy oil reservoirs. On the one hand, the light components are injected into the oil well by distillation to reduce the amount of dilute oil mixed with the wellbore when the wellbore is lifted. The technical scheme is: according to the mass ratio of dilute oil to heavy oil 0.4-1.0, it is mixed into the wellbore to reduce the viscosity of the heavy oil; then the dilute heavy oil is extracted from the well, heated by a heat exchanger, and heated to 350 ℃ in a heating furnace, Enter the distillation tower, collect the distillate oil before 350℃, cool it down by the heat exchanger, and inject it into the wellbore to dilute the heavy oil for recycling; after 350℃, the heavy distillate oil is pumped to the heating furnace to heat up to 370℃-420℃, and then added by the pump The upgrading catalyst is fed into the reaction tower together; in the reaction tower, under the action of the upgrading catalyst, the heavy distillate oil is catalytically upgraded to a low-viscosity heavy oil, and the upgraded heavy oil is directly exported after heat exchange. The essence of this technical solution is to collect the pre-distillate oil at 350°C and cool it to 60°C and then inject it into the wellbore to reduce the viscosity of the heavy oil flowing from the formation through diluting. The problem of increased oil viscosity and poor fluidity has not been proposed to inject light fractions into the formation to recover the high viscosity heavy oil in the formation.
可见，目前向油井中注入稀油，包括发明专利“一种稠油催化改质降粘采输一体化方法及其装置”(参考文献12)的技术方案，均是用于“井筒”掺稀降粘采油和近井地带解堵，而不是向油藏的“地层”中注入低粘油进而替代现有注蒸汽技术开采地层中难采的稠油或高凝油。因此，对于稠油油藏和高凝油油藏，现有方法和工艺只是注高温“水”蒸汽开采的辅助措施，而无法从根本上解决注高温“水”蒸汽存在的能耗大和成本高等核心问题，也无法替代注蒸汽开采稠油油藏 和高凝油油藏。It can be seen that the current injection of thin oil into oil wells, including the technical solutions of the invention patent "An integrated method for catalytic upgrading of heavy oil, viscosity reduction, production and transportation, and its device" (Reference 12), are all used for "wellbore" to mix dilute oil. Instead of injecting low-viscosity oil into the "formation" of the reservoir, it can replace the heavy oil or high pour point oil that is difficult to recover in the formation by replacing the existing steam injection technology. Therefore, for heavy oil reservoirs and high pour point oil reservoirs, the existing methods and processes are only auxiliary measures for high-temperature "water" steam injection, and cannot fundamentally solve the high energy consumption and high cost of high-temperature "water" steam injection. The core problem is that it cannot replace steam injection to recover heavy oil reservoirs and high pour point oil reservoirs.
参考文献：references:
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发明内容SUMMARY OF THE INVENTION
为解决上述技术问题，本发明的目的在于提供一种高粘油开采方法，其是通过将高温低粘油注入高粘油油藏的地层对高粘油进行降粘，实现低成本、低能耗的开采。In order to solve the above technical problems, the purpose of the present invention is to provide a high-viscosity oil recovery method, which is to reduce the viscosity of the high-viscosity oil by injecting the high-temperature low-viscosity oil into the formation of the high-viscosity oil reservoir, so as to realize low cost and low energy consumption. mining.
为达到上述目的，本发明提供了一种高粘油的开采方法，其中，该方法是将高温低粘油或者高温低粘油与气体的组合注入高粘油油藏进行吞吐开采的方法；其中，所述高温低粘油或者高温低粘油与气体的组合将地层中的高粘油通过溶解和加热进行降粘，并增加地层压力；其中，所述高温低粘油包括高粘油现场就地蒸馏所得轻质馏分和中间馏分中的一种或两种以上的组合；所述轻质馏分是将经过脱水脱盐处理的高粘油进行常压蒸馏得到的；所述中间馏分是将经过脱水脱盐处理的高粘油进行常压蒸馏得到的重质馏分进行减压蒸馏得到的。In order to achieve the above object, the present invention provides a method for producing high-viscosity oil, wherein the method is a method for injecting high-temperature low-viscosity oil or a combination of high-temperature low-viscosity oil and gas into a high-viscosity oil reservoir for huff and puff production; wherein , the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas reduces the viscosity of the high-viscosity oil in the formation by dissolving and heating, and increases the formation pressure; wherein, the high-temperature and low-viscosity oil includes the high-viscosity oil on-site One or more combinations of light fractions and middle distillates obtained by ground distillation; the light fractions are obtained by carrying out atmospheric distillation of the high-viscosity oil that has undergone dehydration and desalination; the middle fractions are obtained by dehydrating The heavy fraction obtained by atmospheric distillation of the desalted high-viscosity oil is obtained by vacuum distillation.
本发明的方法是通过将油井采出的高粘油蒸馏得到高温低粘油，然后将高温低粘油注入油藏“地层”中，再进行高粘油的开采。该方法主要利用高温低粘油的稀释降粘和油层加热来提高油藏“地层”中高粘油的流动性，并提高地层压力和驱油，进而提高油井产量和油藏采收率。The method of the invention is to obtain high-temperature and low-viscosity oil by distilling the high-viscosity oil produced from the oil well, and then injecting the high-temperature and low-viscosity oil into the "stratum" of the oil reservoir, and then recovering the high-viscosity oil. This method mainly utilizes the dilution and viscosity reduction of high-temperature and low-viscosity oil and the heating of oil layer to improve the fluidity of high-viscosity oil in the "formation" of the reservoir, and increase the formation pressure and oil displacement, thereby improving oil well production and reservoir recovery.
根据本发明的具体实施方案，优选地，当高粘油蒸馏得到的轻质馏分、中间馏分的含量无法满足注入和吞吐开采的需要时，可以将油田低粘油油藏采出的低粘油(例如稀油等)或其他来源的粘度低于采出高粘油的油与采出高粘油混合进行蒸馏，即以所述经过脱水脱盐处理的高 粘油与低粘油的混合物进行常压蒸馏。尤其在油田现场就地对高粘油进行蒸馏时，有些情况下会出现生产井采出的高粘油中的轻质馏分和中间馏分的含量无法满足注入和吞吐开采需要的情况，此时可以加入其它来源的低粘油一并进行蒸馏。这样能够更加便捷地实施本发明的技术方案，更好地实现高粘油的开采。According to a specific embodiment of the present invention, preferably, when the content of light fractions and middle fractions obtained by distillation of high-viscosity oil cannot meet the needs of injection and huff and puff production, the low-viscosity oil produced from the low-viscosity oil reservoir in the oilfield can be recovered. (such as thin oil, etc.) or oil with a viscosity lower than the produced high-viscosity oil from other sources is mixed with the produced high-viscosity oil for distillation, that is, the mixture of the dehydrated and desalted high-viscosity oil and the low-viscosity oil is used for distillation. pressure distillation. Especially in the on-site distillation of high-viscosity oil in the oil field, in some cases, the content of light distillate and middle distillate in the high-viscosity oil produced by the production well cannot meet the needs of injection and huff and puff production. Distillation was carried out with addition of low viscosity oils from other sources. In this way, the technical solution of the present invention can be implemented more conveniently, and the exploitation of high-viscosity oil can be better realized.
根据本发明的具体实施方案，优选地，在高温低粘油与气体的组合中，所述气体包括天然气、氮气、二氧化碳和烟道气中的一种或两种以上的组合。According to a specific embodiment of the present invention, preferably, in the combination of high temperature and low viscosity oil and gas, the gas includes one or a combination of two or more of natural gas, nitrogen, carbon dioxide and flue gas.
根据本发明的具体实施方案，优选地，当采用高温低粘油与气体的组合时，所述将高温低粘油与气体的组合注入高粘油油藏的地层按照将二者进行同时注入或段塞式注入的方式，其中，所述同时注入是采用使高温低粘油和气体在地面管线混合、井口混合或井底混合的方式进行，即气体的注入方式可以为地面管线混合、井口混合、井底混合(分别由油管和油管与套管的环形空间注入后在井底混合，所述混合是指气体与高温低粘油的混合)，以及所述段塞式注入是在注入高温低粘油之前、注入高温低粘油之后或者注入高温低粘油过程中将气体以段塞式注入。According to a specific embodiment of the present invention, preferably, when a combination of high-temperature and low-viscosity oil and gas is used, the injection of the combination of high-temperature and low-viscosity oil and gas into the formation of a high-viscosity oil reservoir is performed according to simultaneous injection of the two or The method of slug injection, wherein the simultaneous injection is performed by mixing high temperature and low viscosity oil and gas in the surface pipeline, wellhead mixing or bottom hole mixing, that is, the gas injection method can be surface pipeline mixing, wellhead mixing , bottom-hole mixing (respectively injected by the tubing and the annular space between the tubing and the casing, the mixing is at the bottom of the hole, the mixing refers to the mixing of gas and high-temperature and low-viscosity oil), and the slug injection is injected at high temperature and low viscosity. The gas is injected in a slug type before the viscous oil, after the injection of the high temperature and low viscosity oil, or during the injection of the high temperature and low viscosity oil.
根据本发明的具体实施方案，优选地，所述常压蒸馏的温度为350℃-360℃。According to a specific embodiment of the present invention, preferably, the temperature of the atmospheric distillation is 350°C-360°C.
根据本发明的具体实施方案，优选地，所述减压蒸馏的温度为350℃-370℃。According to a specific embodiment of the present invention, preferably, the temperature of the vacuum distillation is 350°C-370°C.
根据本发明的具体实施方案，优选地，所述脱水脱盐处理的高粘油的含水率为5％以下。According to a specific embodiment of the present invention, preferably, the water content of the high-viscosity oil treated by dehydration and desalination is below 5%.
根据本发明的具体实施方案，优选地，所述常压蒸馏和所述减压蒸馏采用油田生产井采出的高粘油在采油现场经过沉降处理、脱水脱盐处理之后进行，即可以采用现场就地蒸馏的方式进行。According to a specific embodiment of the present invention, preferably, the atmospheric distillation and the vacuum distillation are carried out using high-viscosity oil produced from oilfield production wells after sedimentation treatment and dehydration and desalination treatment at the oil production site. carried out by means of local distillation.
根据本发明的具体实施方案，优选地，现场就地蒸馏的装置是由具有换热功能的沉降罐和脱水脱盐处理罐、常压加热炉、常压塔、减压加热炉、减压塔(又称减压蒸馏塔)、缓存罐和泵组成，其中，沉降罐的出口经管线与脱水脱盐处理罐的入口相连，脱水脱盐处理罐的出口通过管线与常压加热炉相连，常压加热炉的出口通过管线与常压塔的中下部相连，常压塔的底部通过管线与减压加热炉的入口相连，减压加热炉的出口通过管线与减压塔的下部相连，常压塔的顶部和减压塔的顶部通过管线与脱水脱盐处理罐的内部换热器的入口和沉降罐的内部换热器的入口相连，减压塔的底部连接减压渣油输出管，脱水脱盐处理罐的换热器的出口通过管线与低粘油缓存罐的入口相连，低粘油缓存罐的出口与高粘油生产井的井口相连，气体注入管线也与高粘油生产井的井口相连，以便将蒸馏得到的馏分作为高温低粘油注入生产井。According to a specific embodiment of the present invention, preferably, the device for on-site distillation is composed of a settling tank with heat exchange function, a dehydration and desalination treatment tank, an atmospheric heating furnace, an atmospheric tower, a vacuum heating furnace, a vacuum tower ( Also known as vacuum distillation tower), buffer tank and pump, wherein the outlet of the sedimentation tank is connected to the inlet of the dehydration and desalination treatment tank through a pipeline, and the outlet of the dehydration and desalination treatment tank is connected to the atmospheric pressure heating furnace through a pipeline, and the atmospheric pressure heating furnace The outlet is connected to the middle and lower part of the atmospheric tower through a pipeline, the bottom of the atmospheric tower is connected to the inlet of the decompression heating furnace through a pipeline, the outlet of the decompression heating furnace is connected to the lower part of the decompression tower through a pipeline, and the top of the atmospheric tower is connected to the lower part of the decompression tower through a pipeline. And the top of the decompression tower is connected with the inlet of the internal heat exchanger of the dehydration and desalination treatment tank and the inlet of the inner heat exchanger of the settling tank through the pipeline, the bottom of the decompression tower is connected with the vacuum residue output pipe, and the bottom of the dehydration and desalination treatment tank is connected. The outlet of the heat exchanger is connected to the inlet of the low-viscosity oil buffer tank through a pipeline, the outlet of the low-viscosity oil buffer tank is connected to the wellhead of the high-viscosity oil production well, and the gas injection pipeline is also connected to the wellhead of the high-viscosity oil production well, so as to The fractions obtained by distillation are injected into production wells as high-temperature, low-viscosity oil.
根据本发明的具体实施方案，优选地，实施现场就地蒸馏是将采出的稠油或高凝油等高粘油在采油井场、联合站、中转站、靠近油田的炼油厂等采油现场就地蒸馏。所述现场就地蒸馏可以包括以下步骤：将生产井采出的高粘油通过泵注入沉降罐进行一次脱水和脱砂处理；经过一次脱水和脱砂处理后的高粘油再通过泵注入脱水脱盐处理罐进行深度脱水和脱盐处理，高粘油含水率优选降至5％以下；将脱水脱盐处理后的高粘油通过泵注入常压加热炉，将高粘油加热(常压蒸馏温度优选350℃-360℃)后进入常压蒸馏塔进行常压蒸馏得到轻质馏分和重质馏分，再将重质馏分通过泵注入减压加热炉，将高粘油加热(减压蒸馏温度优选350℃-370℃)后进入减压蒸馏塔进行减压蒸馏得到中间馏分和减压渣油，最终得到轻质馏分、中间馏分和重质渣油三种馏分。重质渣油经过换热后外输或作为现场蒸馏加热等的燃料，轻质馏分、中间馏分或者二者按照一定比例混合(或者进一步加入低粘油)作为开采用高温低粘油，经过脱水脱盐处理罐和沉降罐内部换热器降温后进入缓存罐，缓存罐中的高温低粘油可通过泵注入高粘油生产井。According to a specific embodiment of the present invention, preferably, in-situ distillation is implemented by placing the produced heavy oil or high-point oil and other high-viscosity oil at the oil production site, such as an oil production well site, a combined station, a transfer station, an oil refinery close to the oil field, etc. Distilled in situ. The on-site in-situ distillation may include the following steps: injecting the high-viscosity oil produced from the production well into the settling tank through a pump for primary dehydration and desanding; The desalination treatment tank is subjected to deep dehydration and desalination treatment, and the moisture content of the high-viscosity oil is preferably reduced to below 5%; 350℃-360℃) and then enter the atmospheric distillation tower for atmospheric distillation to obtain light fractions and heavy fractions, and then inject the heavy fractions into the vacuum heating furnace through a pump, and heat the high-viscosity oil (the vacuum distillation temperature is preferably 350 ℃). ℃-370℃) and then enter the vacuum distillation tower for vacuum distillation to obtain middle distillate and vacuum residue, and finally obtain three fractions of light distillate, middle distillate and heavy residue. After heat exchange, heavy residual oil is exported or used as fuel for on-site distillation heating. The heat exchanger inside the desalination treatment tank and the settling tank cools down and enters the buffer tank. The high-temperature and low-viscosity oil in the buffer tank can be injected into the high-viscosity oil production well through the pump.
根据本发明的具体实施方案，优选地，该开采方法通过油管(优选隔热油管)将高温低粘油注入高粘油油藏地层。According to a specific embodiment of the present invention, preferably, the production method injects high-temperature and low-viscosity oil into a high-viscosity oil reservoir formation through an oil pipe (preferably an insulated oil pipe).
根据本发明的具体实施方案，优选地，注入高粘油油藏地层的高温低粘油或高温低粘油与气体的组合的温度控制在安全注入温度以下；该低粘油安全注入温度根据所述高温低粘油或高温低粘油与气体的组合的最低着火温度来确定。According to a specific embodiment of the present invention, preferably, the temperature of the high-temperature low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas injected into the high-viscosity oil reservoir formation is controlled below the safe injection temperature; the low-viscosity oil safe injection temperature is controlled according to the The minimum ignition temperature of the high temperature and low viscosity oil or the combination of high temperature and low viscosity oil and gas is determined.
根据本发明的具体实施方案，高温低粘油的安全注入温度要兼顾注入油藏取得较好的采油效果、安全注入而不会着火、以及低于油井管柱与工具设备的温度限制。单纯注入高温低粘油的最高注入温度优选为100℃-240℃，当注入高温低粘油与气体(例如氮气、二氧化碳、惰性气体)的组合时，气体能够起到一定的保护作用，高温低粘油的注入温度可提高至240℃-300℃。According to the specific embodiment of the present invention, the safe injection temperature of high temperature and low viscosity oil should take into account the injection into the reservoir to achieve better oil recovery effect, safe injection without fire, and lower than the temperature limit of oil well tubing string and tools and equipment. The maximum injection temperature for simply injecting high-temperature and low-viscosity oil is preferably 100°C-240°C. When injecting a combination of high-temperature and low-viscosity oil and gas (such as nitrogen, carbon dioxide, and inert gas), the gas can play a certain protective role. The injection temperature of viscous oil can be increased to 240℃-300℃.
根据本发明的具体实施方案，优选地，所述最低着火温度根据所述高温低粘油或高温低粘油与气体的组合的着火温度来估算，并通过着火模拟实验来确定。According to a specific embodiment of the present invention, preferably, the minimum ignition temperature is estimated according to the ignition temperature of the high temperature and low viscosity oil or the combination of the high temperature and low viscosity oil and gas, and is determined through ignition simulation experiments.
根据本发明的具体实施方案，优选地，所述着火模拟实验采用着火模拟实验装置进行，该着火模拟实验装置至少包括：第一注入泵、第一中间容器、高温箱、加热盘管、回压阀、可视燃烧釜、收集器、气瓶(包括空气气瓶、氧气气瓶和氮气气瓶等)、压力表；其中，所述第一注入泵通过管线与第一中间容器的底部相连，第一中间容器的上部出口通过管线与高温箱中的加热盘管的入口相连，所述加热盘管的出口通过管线与回压阀相连，所述回压阀通过管线与所述可视燃烧釜相连，所述可视燃烧釜的上部通过管线与所述空气气瓶、氧气气瓶和氮气气瓶分别相连，管线上安装有压力表，所述可视燃烧釜的下部通过管线与所述收集器相连；优选地，所述着火模拟实验装置还包括第二注入泵和第二中间容器，所述第二注入泵通过管线与第二中间容器的底部相连，第二中间容器的上部出口通过管线与高温箱中的加热盘管的入口相连。上述着火模拟实验装置的部分部件优选满足以下条件：所述注入泵的最高注入压力为30MPa-70MPa，所述高温箱的最高加热温度在500℃以上、控温精度≤±0.5℃，所述回压阀的控压范围为0-70MPa，加热盘管的长度为10m-20m、直径为3mm、耐压30MPa-70MPa，所述可视燃烧釜的实验压力范围为0-10MPa、并配备耐压视窗和加热控温系统；所述加热盘管与所述可视燃烧釜之间的管线设有保温部件，例如绝缘材料。According to a specific embodiment of the present invention, preferably, the ignition simulation experiment is performed using an ignition simulation experimental device, and the ignition simulation experimental device at least includes: a first injection pump, a first intermediate container, a high temperature box, a heating coil, a back pressure valve, visual combustion kettle, collector, gas cylinder (including air cylinder, oxygen cylinder and nitrogen cylinder, etc.), pressure gauge; wherein, the first injection pump is connected to the bottom of the first intermediate container through a pipeline, The upper outlet of the first intermediate container is connected to the inlet of the heating coil in the high temperature box through a pipeline, the outlet of the heating coil is connected to a back pressure valve through a pipeline, and the back pressure valve is connected to the visible combustion kettle through a pipeline Connected, the upper part of the visual combustion kettle is connected to the air cylinder, the oxygen cylinder and the nitrogen cylinder respectively through pipelines, a pressure gauge is installed on the pipeline, and the lower part of the visual combustion kettle is connected to the collector through pipelines. Preferably, the ignition simulation experiment device further includes a second injection pump and a second intermediate container, the second injection pump is connected to the bottom of the second intermediate container through a pipeline, and the upper outlet of the second intermediate container is connected through a pipeline Connected to the inlet of the heating coil in the high temperature box. Some components of the above-mentioned ignition simulation experimental device preferably meet the following conditions: the maximum injection pressure of the injection pump is 30MPa-70MPa, the maximum heating temperature of the high temperature box is above 500°C, the temperature control accuracy is ≤±0.5°C, and the return temperature is ≤±0.5°C. The pressure control range of the pressure valve is 0-70MPa, the length of the heating coil is 10m-20m, the diameter is 3mm, and the pressure resistance is 30MPa-70MPa. The experimental pressure range of the visual combustion kettle is 0-10MPa, and equipped with pressure resistance A viewing window and a heating and temperature control system; the pipeline between the heating coil and the visible combustion kettle is provided with thermal insulation components, such as insulating materials.
根据本发明的具体实施方案，优选地，所述着火模拟实验包括以下步骤：According to a specific embodiment of the present invention, preferably, the ignition simulation experiment includes the following steps:
根据高温低粘油的组成选择相应的馏分和/或低粘油制成实验样品或者将高温低粘油直接作为实验样品；将实验样品加入第一中间容器，通过第一注入泵加压使低粘油分注入高温箱中的加热盘管(当需要注入气体时，气体加入第二中间容器，通过第二注入泵加压使气体与实验样品混合后进入高温箱中的加热盘管)，高温箱设定温度为实验温度，通过回压阀将加热至实验温度的实验样品控制在实验压力水平，使高温高压的实验样品进入设定温度、压力和气体环境下的可视燃烧釜，通过视窗观察流进可视燃烧釜的实验样品是否着火；其中，所述回压阀控制的实验压力根据现场高温低粘油或高温低粘油与气体的组合的注入压力来设定，所述可视燃烧釜的温度、压力和气体环境模拟可能发生泄漏的环境；所述高温箱的加热温度根据注入实验样品可能着火的温度来确定，实验时根据实验样品的组成预估最低着火温度，并上调和下调一定温度(优选5℃-10℃)进行着火模拟实验，并根据着火模拟实验结果放大或缩小调整着火模拟实验的加热温度，直至测定实验样品的最低着火温度；将最低着火温度乘以安全系数可得相应的高温低粘油的安全注入温度；优选地，所述着火温度预估可根据实验样品的组成以及各组成 成分的着火温度进行体积加权平均或者质量加权平均来估算。According to the composition of high-temperature and low-viscosity oil, select the corresponding fraction and/or low-viscosity oil to make the experimental sample, or directly use the high-temperature and low-viscosity oil as the experimental sample; add the experimental sample to the first intermediate container, and pressurize the low-viscosity oil through the first injection pump. The viscous oil is injected into the heating coil in the high temperature box (when gas needs to be injected, the gas is added to the second intermediate container, and the gas is mixed with the experimental sample by the second injection pump and then enters the heating coil in the high temperature box), high temperature box The set temperature is the experimental temperature, and the experimental sample heated to the experimental temperature is controlled at the experimental pressure level through the back pressure valve, so that the experimental sample of high temperature and high pressure enters the visual combustion kettle under the set temperature, pressure and gas environment, and is observed through the window Whether the experimental sample flowing into the visual combustion kettle catches fire; wherein, the experimental pressure controlled by the back pressure valve is set according to the injection pressure of the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas on site, and the visual combustion The temperature, pressure and gas environment of the kettle simulate the environment where leakage may occur; the heating temperature of the high-temperature box is determined according to the temperature at which the injected experimental sample may ignite. During the experiment, the minimum ignition temperature is estimated according to the composition of the experimental sample, and adjusted up and down Carry out the ignition simulation experiment at a certain temperature (preferably 5°C-10°C), and adjust the heating temperature of the ignition simulation experiment according to the results of the ignition simulation experiment, until the minimum ignition temperature of the experimental sample is determined; multiplying the minimum ignition temperature by the safety factor can The corresponding safe injection temperature of the high-temperature and low-viscosity oil is obtained; preferably, the estimated ignition temperature can be estimated by performing a volume-weighted average or a mass-weighted average based on the composition of the experimental sample and the ignition temperature of each component.
根据本发明的具体实施方案，优选地，在注入高粘油油藏地层之前，所述高温低粘油先与进行沉降处理和/或脱水脱盐处理的高粘油进行换热，以使其降温至安全注入温度。具体可以采用以下方式：将高温低粘油通过采出高粘油的沉降罐和脱水脱盐处理罐进行换热，在加热罐中的采出高粘油的同时，使高温低粘油适当降温至安全注入温度。According to a specific embodiment of the present invention, preferably, before injecting into a high-viscosity oil reservoir formation, the high-temperature and low-viscosity oil is heat-exchanged with the high-viscosity oil subjected to sedimentation treatment and/or dehydration and desalination treatment to lower the temperature to safe injection temperature. Specifically, the following methods can be used: exchanging heat with the high-temperature and low-viscosity oil through the sedimentation tank for producing the high-viscosity oil and the dehydration and desalting treatment tank, and at the same time as the high-viscosity oil is produced in the heating tank, the high-temperature and low-viscosity oil is appropriately cooled down to Safe injection temperature.
根据本发明的具体实施方案，优选地，本发明所提供的开采方法是通过将油井采出原油在采油现场就地蒸馏得到高温低粘油馏分并通过脱水脱盐处理罐和沉降罐经过适当换热降温至安全注入温度，采用低温低粘油、气体或水等顶替介质将高粘油生产井油管和油管与套管环空中气体顶替后，将高温低粘油馏分通过油井的油管注入油藏“地层”中，同时可注入气体等其他介质，停注焖井一段时间后进行采油，当开采一定时间或者产量降至一定水平时转入下一周期吞吐开采。本发明所提供的开采方法可以包括以下步骤：According to a specific embodiment of the present invention, preferably, the production method provided by the present invention is to obtain high-temperature and low-viscosity oil fractions by in-situ distillation of crude oil produced from oil wells at the oil production site, and to pass appropriate heat exchange through a dehydration desalination treatment tank and a settling tank. Cool down to a safe injection temperature, and use low-temperature and low-viscosity oil, gas or water and other displacement media to replace the high-viscosity oil production well tubing and tubing with the gas in the casing annulus, and then inject the high-temperature and low-viscosity oil fractions into the reservoir through the tubing of the oil well. At the same time, other media such as gas can be injected into the stratum, and oil production can be carried out after stopping the injection and soaking for a period of time. The mining method provided by the present invention may comprise the following steps:
(1)通过油管和油套环空向高粘油生产井注入顶替介质顶替油管和油套环空中的空气，优选地，所述顶替介质包括低温低粘油、气体和水中的一种或两种以上的组合；(1) injecting a displacement medium into the high-viscosity oil production well through the tubing and the oil-casing annulus to displace the air in the tubing and the oil-casing annulus, preferably, the displacement medium includes one or two of low-temperature and low-viscosity oil, gas and water more than one combination;
(2)将高温低粘油通过生产井的油管注入高粘油油藏的地层中，所述高温低粘油的注入量根据高粘油粘度、油藏开采程度和油井类型来确定；(2) injecting the high-temperature and low-viscosity oil into the formation of the high-viscosity oil reservoir through the tubing of the production well, and the injection amount of the high-temperature and low-viscosity oil is determined according to the viscosity of the high-viscosity oil, the degree of reservoir exploitation and the type of oil well;
(3)在注入高温低粘油的过程中或者注入高温低粘油之后，通过油管和/或油套环空注入气体，以扩大注入的高温低粘油的地层波及范围；其中，所述注入气体与低粘油在大气压下的体积比优选根据低粘油注入量、气体在低粘油中的溶解度、气体波及范围、波及范围内地层流体饱和度、以及所要达到的油层压力来确定；(3) In the process of injecting high-temperature and low-viscosity oil or after injecting high-temperature and low-viscosity oil, gas is injected through the oil pipe and/or the oil jacket annulus, so as to expand the stratum swept range of the injected high-temperature and low-viscosity oil; wherein, the injection The volume ratio of the gas to the low-viscosity oil under atmospheric pressure is preferably determined according to the injection amount of the low-viscosity oil, the solubility of the gas in the low-viscosity oil, the gas swept range, the formation fluid saturation in the swept range, and the oil formation pressure to be achieved;
(4)注入结束并焖井一段时间后，油井开井生产。(4) After the injection is completed and the well is held for a period of time, the oil well is opened for production.
根据本发明的具体实施方案，优选地，当油井开采一段时间且油井产量降至一定水平后，结束本周期开采，转下一周期注高温低粘油或高温低粘油与气体的组合进行吞吐。其中，重复上述步骤(1)-(4)称为一个周期。According to a specific embodiment of the present invention, preferably, after the oil well has been developed for a period of time and the production of the oil well has dropped to a certain level, the current cycle of production is terminated, and the next cycle of injection of high-temperature and low-viscosity oil or a combination of high-temperature and low-viscosity oil and gas is performed for huff and puff. . Wherein, repeating the above steps (1)-(4) is called one cycle.
根据本发明的具体实施方案，优选地，当利用现场就地蒸馏低粘油馏分吞吐开采高粘油时，该开采方法包括以下具体步骤：According to a specific embodiment of the present invention, preferably, when utilizing on-site distillation of low-viscosity oil fractions to huff and puff to recover high-viscosity oil, the recovery method comprises the following specific steps:
a.将油田生产井采出的高粘油在采油现场进行脱水和脱盐处理后，加热至350℃-360℃后进行常压蒸馏得到轻质馏分和重质馏分，再将重质馏分加热至350℃-370℃后进行减压蒸馏得到中间馏分和减压渣油，最终得到轻质馏分、中间馏分和重质馏分三种馏分，可将其中的轻质馏分、中间馏分或者将按照一定比例混合得到开采用的高温低粘油。a. After dehydration and desalination treatment of the high-viscosity oil produced from the production well in the oil field, it is heated to 350℃-360℃, and then subjected to atmospheric distillation to obtain light fractions and heavy fractions, and then the heavy fractions are heated to After 350℃-370℃, vacuum distillation is carried out to obtain middle distillate and vacuum residue, and finally three fractions of light distillate, middle distillate and heavy distillate are obtained. Mixed to obtain the high temperature and low viscosity oil used for development.
b.将高温低粘油通过采出高粘油的沉降罐和脱水脱盐处理罐进行换热，在将罐中采出高粘油加热的同时，使高温低粘油适当降温至安全注入温度。b. Heat the high-temperature and low-viscosity oil through the settling tank for producing high-viscosity oil and the dehydration and desalting treatment tank. While heating the high-viscosity oil produced in the tank, the high-temperature and low-viscosity oil is appropriately cooled to a safe injection temperature.
c.通过油管和油管与套管环形空间向注低粘油馏分吞吐开采的高粘油生产井注入低温低粘油、气体或水等顶替介质，顶替油管和油管与套管环形空间中的空气，保证后续注入高温低粘油的安全。c. Inject low-temperature and low-viscosity oil, gas or water and other displacement media into the high-viscosity oil production well that injects low-viscosity oil fractions through the annular space of the tubing and the tubing and casing to displace the air in the annular space of the tubing, tubing and casing , to ensure the safety of subsequent injection of high temperature and low viscosity oil.
d.将换热后的高温低粘油通过高粘油生产井的油管注入高粘油油藏的地层中。d. The high-temperature and low-viscosity oil after heat exchange is injected into the formation of the high-viscosity oil reservoir through the tubing of the high-viscosity oil production well.
e.在注入高温低粘油过程中或者注入高温低粘油后，通过油管和/或油套环空注入气体，扩大注入高温低粘油的地层波及范围。e. In the process of injecting high temperature and low viscosity oil or after injecting high temperature and low viscosity oil, inject gas through the oil pipe and/or the oil casing annulus to expand the scope of the formation where the high temperature and low viscosity oil is injected.
f.注入结束并焖井一段时间后，油井开井生产，在注入气体驱动及重力、弹性能等油藏天 然能量作用下，地层中被注入低粘油稀释和加热的高粘油流向井底并采出，提高地层高粘油的开采速度和采收率。f. After the injection is completed and the well is held for a period of time, the oil well is opened for production. Under the action of the injected gas and the natural energy of the reservoir such as gravity and elastic energy, the high-viscosity oil diluted and heated by the injected low-viscosity oil flows to the bottom of the well. And production, improve the production speed and recovery rate of formation high-viscosity oil.
g.当油井生产一段时间且产量降至一定程度后，重新将采出的高粘油进行蒸馏、注入、焖井和采油，如此进行循环吞吐开采，通过现场就地蒸馏利用采出高粘油中的低粘油馏分和辅助的气体将油藏地层中的高粘油不断开采出来，实现通过采出高粘油本身蒸馏所得低粘油回注“带”出油藏高粘油，由于去除了常规注蒸汽开采的水质处理和锅炉产生蒸汽并大幅减少采出水量，使高粘油的开采成本可降至蒸汽吞吐的1/2以下且具有环境友好的优点，可用于替代现有高能耗、高成本的蒸汽吞吐开采方法。g. When the oil well has been produced for a period of time and the output has dropped to a certain level, the extracted high-viscosity oil is re-distilled, injected, simmered and recovered, so as to carry out circulating huff and puff extraction, and the high-viscosity oil is recovered by on-site distillation. The low-viscosity oil fraction in the medium and the auxiliary gas continuously develop the high-viscosity oil in the reservoir formation, so that the low-viscosity oil obtained by the distillation of the high-viscosity oil itself can be reinjected into the “belt” of the high-viscosity oil in the reservoir. The water quality treatment of conventional steam injection production and boiler production of steam greatly reduce the production water volume, so that the production cost of high viscosity oil can be reduced to less than 1/2 of the steam huff and puff, and it has the advantages of environmental friendliness, which can be used to replace the existing high energy consumption. , High-cost steam huff and puff mining method.
根据本发明的具体实施方案，优选地，步骤(1)和步骤c可以按照以下方式进行：在注入高温低粘油之前优选通过油管和油管与套管环形空间向高粘油生产井注入低温低粘油、气体或水等顶替介质，顶替油管和油管与套管环形空间中的空气，保证后续注入高温低粘油的安全。所述注入气体可为氮气或二氧化碳等。所述顶替方式可直接在高压下将低温低粘油、气体或水等顶替介质通过油管和油管与套管环空注入地层，也可将低温低粘油、气体或水等顶替介质从油管注入并从油管和套管环空采出循环顶替井中空气等气体，也可将低温低粘油、气体或水等顶替介质从油管和套管环空注入并从油管采出循环顶替井中空气等气体。According to a specific embodiment of the present invention, preferably, step (1) and step c can be carried out in the following manner: before injecting high-temperature and low-viscosity oil, inject low-temperature, low-viscosity oil into a high-viscosity oil production well, preferably through an annulus of tubing and tubing and casing. Substitute medium such as viscous oil, gas or water to displace the air in the annular space between the tubing and the tubing and casing, ensuring the safety of subsequent injection of high-temperature and low-viscosity oil. The injection gas can be nitrogen, carbon dioxide, or the like. The displacement method can directly inject low-temperature and low-viscosity oil, gas or water and other displacement media into the formation under high pressure through the oil pipe, the oil pipe and the casing annulus, and can also inject the low-temperature low-viscosity oil, gas or water and other displacement media from the oil pipe. And the gas such as air in the circulating displacement well can be produced from the tubing and casing annulus, and the displacement medium such as low-temperature and low-viscosity oil, gas or water can also be injected from the tubing and casing annulus, and the gas such as air in the circulating displacement well can be produced from the tubing. .
根据本发明的具体实施方案，优选地，在步骤(2)中，所述高温低粘油的注入量、高温低粘油与气体的组合时低粘油的注入量根据高粘油粘度、油藏开采程度和油井类型来确定。According to a specific embodiment of the present invention, preferably, in step (2), the injection amount of the high-temperature low-viscosity oil, the injection amount of the low-viscosity oil when the high-temperature low-viscosity oil is combined with the gas is based on the viscosity of the high-viscosity oil, the oil The degree of reservoir exploitation and the type of oil well are determined.
根据本发明的具体实施方案，优选地，所述油藏开采程度根据油藏可波及半径来表征，所述油藏可波及半径为已动用油藏外边界到生产井的距离；当为新投产直井或定向井第一周期时，油藏可波及半径可以为3m-5m，即新投产直井或定向井第一周期采用注入低粘油吞吐开采时油藏可波及半径可取3m-5m；当为新投产水平井、分支井和鱼骨井第一周期时，油藏可波及半径可以为1m-3m，即新投产水平井、分支井和鱼骨井第一周期采用注入低粘油吞吐开采时油藏可波及半径可取1m-3m。According to a specific embodiment of the present invention, preferably, the degree of recovery of the oil reservoir is characterized by the swept radius of the oil reservoir, and the swept radius of the oil reservoir is the distance from the outer boundary of the produced oil reservoir to the production well; when it is newly put into production In the first cycle of vertical wells or directional wells, the swept radius of the reservoir can be 3m-5m, that is, the swept radius of the reservoir can be 3m-5m when the low-viscosity oil is injected into huff and puff in the first cycle of newly put into production vertical wells or directional wells; In the first cycle of newly put into production horizontal wells, branch wells and fishbone wells, the swept radius of the reservoir can be 1m-3m, that is, when the first cycle of newly put into production horizontal wells, branch wells and fishbone wells adopts low-viscosity oil injection and huff and puff production The swept radius of the reservoir can be 1m-3m.
根据本发明的具体实施方案，优选地，所述吞吐开采高粘油时的高温低粘油的注入强度为每米油层周期注入高温低粘油的量，或高温低粘油与气体的组合时的高温低粘油的量，可根据下式计算：According to a specific embodiment of the present invention, preferably, the injection intensity of the high-temperature and low-viscosity oil during huff and puff production of high-viscosity oil is the amount of high-temperature and low-viscosity oil injected per meter of oil layer period, or the combination of high-temperature and low-viscosity oil and gas The amount of high temperature and low viscosity oil can be calculated according to the following formula:
I o＝[a+b ln(R/h)]·[c ln ln(μ)-d] I o =[a+b ln(R/h)]·[c ln ln(μ)-d]
式中，I o为低粘油注入强度，m 3/m；a和b为与油藏动用程度有关的参数，c和d为与高粘油粘度有关的参数，可根据目标油藏条件通过油藏数值模拟或现场应用结果来确定；R为油藏可波及半径，m；h为油藏厚度，m；μ为地层条件下高粘油的粘度，mPa·s； In the formula, I o is the injection strength of low-viscosity oil, m 3 /m; a and b are parameters related to the degree of reservoir production, c and d are parameters related to the viscosity of high-viscosity oil, which can be passed according to the target reservoir conditions. Reservoir numerical simulation or field application results to determine; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; μ is the viscosity of high-viscosity oil under formation conditions, mPa s;
优选地，当生产井为直井或定向井时，所述高温低粘油的注入强度为：Preferably, when the production well is a vertical well or a directional well, the injection strength of the high temperature and low viscosity oil is:
I ho＝[1+0.15ln(R/h)]·[120ln ln(μ)-150] I ho =[1+0.15ln(R/h)]·[120lnln(μ)-150]
式中，I ho为高温低粘油的注入强度，m 3/m；R为油藏可波及半径，m；h为油藏厚度，m；μ为地层条件下高粘油的粘度，mPa·s； In the formula, I ho is the injection strength of high temperature and low viscosity oil, m 3 /m; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; μ is the viscosity of high viscosity oil under formation conditions, mPa· s;
优选地，当生产井为水平井、分支井或鱼骨井时，所述高温低粘油的注入强度为：Preferably, when the production well is a horizontal well, a lateral well or a fishbone well, the injection strength of the high temperature and low viscosity oil is:
I ho＝[1+0.1ln(R/h)]·[12ln ln(μ)-15] I ho =[1+0.1ln(R/h)]·[12lnln(μ)-15]
式中，I ho为高温低粘油的注入强度，m 3/m；R为油藏可波及半径，m；h为油藏厚度，m； μ为地层条件下高粘油的粘度，mPa·s。 In the formula, I ho is the injection strength of high temperature and low viscosity oil, m 3 /m; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; μ is the viscosity of high viscosity oil under formation conditions, mPa· s.
根据本发明的具体实施方案，优选地，在步骤(3)中，在所述高温低粘油与气体的组合中，气体(即在注入高温低粘油的过程中或者注入高温低粘油之后，通过油管和/或油套环空注入的气体)与所述高温低粘油在大气压下的体积比根据低粘油注入量、气体在低粘油中的溶解度、气体波及范围、波及范围内地层流体饱和度、以及所要达到的油层压力来确定；其中，所述气体波及范围根据油藏可波及半径、油层厚度和油层孔隙度来计算，所述油藏可波及半径为已动用油藏外边界到油井的距离；所述注入气体与低粘油在大气压下的体积比优选根据下式计算：According to a specific embodiment of the present invention, preferably, in step (3), in the combination of the high-temperature and low-viscosity oil and the gas, the gas (that is, during the injection of the high-temperature and low-viscosity oil or after the high-temperature and low-viscosity oil is injected , the volume ratio of the gas injected through the oil pipe and/or the oil jacket annulus) to the high temperature and low viscosity oil under atmospheric pressure is based on the injection amount of the low viscosity oil, the solubility of the gas in the low viscosity oil, the gas sweep range, and the sweep range. The gas swept range is calculated according to the swept radius of the reservoir, the thickness of the oil layer and the porosity of the oil layer, and the swept radius of the oil reservoir is outside the produced oil reservoir. The distance from the boundary to the oil well; the volume ratio of the injected gas to the low-viscosity oil under atmospheric pressure is preferably calculated according to the following formula:
Figure PCTCN2021075005-appb-000001
Figure PCTCN2021075005-appb-000001
式中，IGOR为注入气体与低粘油在大气压下的体积比；I o为低粘油注入强度，m 3/m；D g为注入气体在注入油藏低粘油中的溶解度；R为油藏可波及半径，m；φ为油层平均孔隙度；S o为油藏波及范围内的油饱和度；S w为油藏波及范围内的水饱和度；S g为油藏波及范围内的气体饱和度；ΔP为油藏压力增加值，MPa；P 0为大气压力，MPa。 where IGOR is the volume ratio of injected gas to low-viscosity oil at atmospheric pressure; I o is the injection strength of low-viscosity oil, m 3 /m; D g is the solubility of injected gas in low-viscosity oil injected into the reservoir; R is Reservoir swept radius, m; φ is the average porosity of the reservoir; S o is the oil saturation within the swept range of the reservoir; Sw is the water saturation within the swept range of the reservoir; S g is the swept range of the reservoir Gas saturation; ΔP is the increase in reservoir pressure, MPa; P 0 is atmospheric pressure, MPa.
本发明所提供的开采方法是一种将高温低粘油或者高温低粘油与气体的组合注入高粘油油藏进行吞吐开采的方法，其中，在注入过程中，可以根据高粘油油藏的条件和注入低粘油的组成确定安全注入温度和注入强度，在安全注入温度以下、控制适当的注入强度将高温低粘油或者高温低粘油与气体的组合注入高粘油油藏将地层中的高粘油通过溶解和加热进行降粘，并增加地层压力，进行吞吐开采。目前还未见向地层注入低粘油进行吞吐开采高粘油的研究和应用报道，也未见将现场就地蒸馏低粘油馏分注入油藏进行吞吐开采高粘油的研究和应用报道。目前未将向地层注入低粘油进行吞吐作为高粘油藏开采方式的主要原因在于现有观点认为“虽然向高粘油油藏中注入低粘油能够将地层中高粘油的粘度降低，但是，并未明确注入低粘油将地层高粘油采出的效果，无法确定是否能够优于现有的蒸汽吞吐等加热降粘手段，还会造成注入油层低粘油无法采出而造成低粘油损失”，因此，至今仍未见针对向地层注入低粘油开采高粘油的研究和应用，实际上，这是一种偏见，本发明研究发现将采出高粘油高温蒸馏并将其中高温的低粘油注入高粘油油藏，可以通过溶解稀释和加热提高地层中高粘油的流动性并将其快速采出，同时注入的低粘油也会从油藏中“吐”出。由于去除了锅炉用水的水质处理、加热蒸馏原油燃料消耗量明显低于锅炉产生蒸汽的燃料消耗量、采出水量大幅降低，所以，采用向地层注入低粘油吞吐开采高粘油的成本会明显低于蒸汽吞吐等注蒸汽方法。The production method provided by the present invention is a method for injecting high-temperature and low-viscosity oil or a combination of high-temperature and low-viscosity oil and gas into a high-viscosity oil reservoir for huff and puff production. The conditions and the composition of the injected low-viscosity oil determine the safe injection temperature and injection intensity. Below the safe injection temperature, control the appropriate injection intensity to inject the high-temperature low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas into the high-viscosity oil reservoir. The high viscosity oil in the medium is dissolved and heated to reduce the viscosity, increase the formation pressure, and perform huff and puff production. At present, there is no report on the research and application of injecting low-viscosity oil into the formation for huff and puff recovery of high-viscosity oil, nor has there been any report on the research and application of on-site distillation of low-viscosity oil fractions into oil reservoirs for huff-puff recovery of high-viscosity oil. The main reason why injection of low-viscosity oil into the formation for huff and puff is not currently used as a recovery method for high-viscosity reservoirs is that the current view is that “although injecting low-viscosity oil into high-viscosity oil reservoirs can reduce the viscosity of high-viscosity oil in formations, , the effect of injecting low-viscosity oil to recover high-viscosity oil in the formation is not clear, and it is uncertain whether it can be better than the existing heating and viscosity-reducing methods such as steam huff and puff. Therefore, the research and application of injecting low-viscosity oil into the formation to recover high-viscosity oil has not yet been seen. High-temperature low-viscosity oil is injected into a high-viscosity oil reservoir, which can improve the fluidity of the high-viscosity oil in the formation by dissolving, diluting and heating, and quickly recover it. Because the water quality treatment of boiler water is removed, the fuel consumption of heating and distilling crude oil is significantly lower than the fuel consumption of steam generated by the boiler, and the amount of produced water is greatly reduced. Therefore, the cost of producing high-viscosity oil by injecting low-viscosity oil into the formation with huff and puff will be obvious. It is lower than steam injection methods such as steam huff and puff.
本发明的高粘油开采方法具有经济、高效、节能的优势，成本明显低于蒸汽吞吐等注蒸汽开采方法，尤其是在利用现场就地蒸馏低粘油馏分吞吐开采高粘油时。本发明的高粘油开采方法可用于开采稠油、高凝油等高粘油油藏，尤其适用于注蒸汽热采效果差或成本高的高粘油油藏以及由于水敏或水源短缺等原因无法注水或注蒸汽的高粘油油藏。The high-viscosity oil recovery method of the invention has the advantages of economy, high efficiency and energy saving, and the cost is obviously lower than that of steam injection recovery methods such as steam huff and puff, especially when high-viscosity oil is recovered by on-site distillation of low-viscosity oil fractions and huff and puff. The high-viscosity oil recovery method of the present invention can be used for the recovery of high-viscosity oil reservoirs such as heavy oil and high-point-point oil, and is especially suitable for high-viscosity oil reservoirs with poor steam injection thermal recovery effect or high cost, and due to water sensitivity or water shortage, etc. The reason is high-viscosity oil reservoirs that cannot be injected with water or steam.
本发明的高粘油开采方法开采高粘油的生产井可以为直井、定向斜井、水平井、分支井、鱼骨井或者其他井型。The high-viscosity oil production method of the present invention can produce high-viscosity oil production wells in vertical wells, directional inclined wells, horizontal wells, lateral wells, fishbone wells or other well types.
本发明的高粘油开采方法的适用范围不限于上述范围，适用于所有可以采用本发明所提供的利用现场就地蒸馏低粘油馏分开采的油藏。The scope of application of the high-viscosity oil recovery method of the present invention is not limited to the above-mentioned scope, and is applicable to all oil reservoirs that can be recovered by using the low-viscosity oil fractions provided by the present invention by on-site distillation.
本发明具有如下有益效果：The present invention has the following beneficial effects:
(1)本发明提供的高粘油开采方法利用采出高粘油蒸馏得到的轻质组分、中间组分和重质 组分，且对组分切割精度要求低，蒸馏工艺相对简单、设备和运行成本相对较低。(1) The high-viscosity oil recovery method provided by the present invention utilizes the light components, intermediate components and heavy components obtained by extracting the high-viscosity oil distillation, and has low requirements on the cutting precision of the components, the distillation process is relatively simple, and the equipment and relatively low operating costs.
(2)当本发明提供的高粘油开采方法利用现场就地蒸馏低粘油馏分吞吐开采高粘油时，现场就地蒸馏得到的高温低粘油可以通过沉降罐和脱水脱盐处理罐换热，在加热沉降罐和脱水脱盐处理罐中高粘油的同时，将低粘油降温至安全注入温度，从而简化工艺，节约能源。(2) When the high-viscosity oil recovery method provided by the present invention utilizes on-site distillation of low-viscosity oil fractions to huff and puff to exploit high-viscosity oil, the high-temperature and low-viscosity oil obtained by on-site distillation can be heat-exchanged by a settling tank and a dehydration desalination treatment tank , while heating the high-viscosity oil in the sedimentation tank and the dehydration and desalination treatment tank, the low-viscosity oil is cooled to a safe injection temperature, thereby simplifying the process and saving energy.
(3)本发明提供的高粘油开采方法通过将采出高粘油蒸馏所得的高温低粘油注入或者与其他介质混合注入油井进行吞吐开采高粘油，利用高温低粘油溶解降粘和油层加热来提高地层中高粘油的流动性，也可起到提高地层压力和驱油作用，进而实现提高油井产量和油藏采收率的作用。(3) In the high-viscosity oil recovery method provided by the present invention, the high-temperature and low-viscosity oil obtained by the distillation of the high-viscosity oil is injected into the oil well or mixed with other media to produce high-viscosity oil by huff and puff. Oil layer heating can improve the fluidity of high-viscosity oil in the formation, and can also improve formation pressure and oil displacement, thereby achieving the effect of improving oil well production and reservoir recovery.
(4)本发明提供的高粘油开采方法通过将采出高粘油蒸馏所得的高温低粘油注入油层进行采油，综合利用高温低粘油的溶解稀释和加热作用来提高原油的流动性，能耗和成本较主要靠加热作用的注高温蒸汽方法明显降低。同时，由于回注高温低粘油利用了蒸馏的热量进一步提高了热效率、降低了成本。(4) the high-viscosity oil recovery method provided by the present invention is by injecting the high-temperature and low-viscosity oil obtained by extracting the high-viscosity oil distillation into the oil layer to carry out oil recovery, and comprehensively utilizes the dissolution, dilution and heating effects of the high-temperature and low-viscosity oil to improve the fluidity of crude oil, Compared with the high temperature steam injection method which mainly relies on heating, the energy consumption and cost are significantly reduced. At the same time, since the re-injection of high-temperature and low-viscosity oil utilizes the heat of distillation, the thermal efficiency is further improved and the cost is reduced.
(5)本发明提供的高粘油开采方法回注的高温低粘油可将地层高粘油溶解稀释，粘度降低且温度敏感性变弱，容易举升和输送，可消除或减轻井筒举升的难度和成本。(5) The high-temperature and low-viscosity oil re-injected by the high-viscosity oil recovery method provided by the present invention can dissolve and dilute the formation high-viscosity oil, reduce the viscosity and weaken the temperature sensitivity, easy to lift and transport, and can eliminate or reduce the wellbore lift difficulty and cost.
(6)本发明提供的高粘油开采方法可将高温蒸馏得到的低粘油和(或)渣油作为蒸馏和发电等工艺过程的燃料，就地取材，降低了开采的燃料成本。(6) The high-viscosity oil extraction method provided by the present invention can use the low-viscosity oil and/or residual oil obtained by high-temperature distillation as the fuel for technological processes such as distillation and power generation.
(7)较常规注高温蒸汽方法，本发明提供的高粘油开采方法大大降低了注入水量和采出水量，减小了地面水处理的难度和成本。(7) Compared with the conventional high-temperature steam injection method, the high-viscosity oil recovery method provided by the present invention greatly reduces the amount of injected water and produced water, and reduces the difficulty and cost of surface water treatment.
(8)本发明提供的高粘油开采方法通过将蒸馏所得高温低粘油回注油层，可将地层高粘油逐渐溶解稀释，可将稠油油藏和高凝油油藏转变为“稀油”油藏，大大降低了开采难度，进而，可以转换为注水、注聚等常规开采方式进行开采。(8) The high-viscosity oil recovery method provided by the present invention can gradually dissolve and dilute the high-viscosity oil in the formation by injecting the high-temperature and low-viscosity oil obtained by distillation back into the oil layer, and can convert heavy oil reservoirs and high-point pour oil reservoirs into "thin oil". Oil" reservoirs greatly reduce the difficulty of exploitation, and further, they can be converted into conventional exploitation methods such as water injection and polymer injection for exploitation.
(9)本发明提供的高粘油开采方法由于综合利用回注高温低粘油的溶解稀释作用和加热作用，并可与其他介质混合进行采油，适用油藏范围广。适用于稠油油藏和高凝油油藏，尤其适用于注蒸汽热采效果差或成本高的高粘油油藏以及由于水敏或水源短缺等原因无法注水或注蒸汽的油藏。(9) The high-viscosity oil recovery method provided by the present invention comprehensively utilizes the dissolution dilution and heating effects of re-injection of high-temperature and low-viscosity oil, and can be mixed with other media for oil recovery, and is suitable for a wide range of oil reservoirs. It is suitable for heavy oil reservoirs and high pour point oil reservoirs, especially for high viscosity oil reservoirs with poor thermal recovery effect or high cost of steam injection, and oil reservoirs where water or steam injection cannot be performed due to water sensitivity or water shortage.
附图说明Description of drawings
图1是实施例1.1的利用蒸馏低粘油馏分吞吐开采高粘油方法的示意图，图中的标记具体含义：1：油层，2：上覆岩层，3：油井，4：高粘油管线，5：泵，6：沉降罐，7：脱水脱盐处理罐，8：盐水管线，9：脱水脱盐处理后高粘油管线，10：常压加热炉，11：常压塔；12：轻质馏分管线，13：重质馏分管线，14：减压加热炉，15：减压塔，16：中间馏分管线，17：减压渣油管线，18：高温低粘油管线，19：降温后低粘油管线，20：缓冲罐，21：高粘油生产井，22：其他介质管线，23：气体作用区域，24：低粘油作用区域；Fig. 1 is a schematic diagram of the method for producing high-viscosity oil by huff and puff of distilled low-viscosity oil fraction according to Example 1.1, the specific meanings of the symbols in the figure are: 1: oil layer, 2: overlying rock layer, 3: oil well, 4: high-viscosity oil pipeline, 5: Pump, 6: Settling tank, 7: Dehydration and desalination treatment tank, 8: Brine pipeline, 9: High-viscosity oil pipeline after dehydration and desalination, 10: Atmospheric pressure heating furnace, 11: Atmospheric pressure tower; 12: Light fraction Pipeline, 13: heavy distillate pipeline, 14: vacuum heating furnace, 15: vacuum tower, 16: middle distillate pipeline, 17: vacuum residue pipeline, 18: high temperature and low viscosity oil pipeline, 19: low viscosity after cooling down Oil pipeline, 20: buffer tank, 21: high viscosity oil production well, 22: other medium pipeline, 23: gas action area, 24: low viscosity oil action area;
图2是按照实施例1.1的利用蒸馏低粘油馏分吞吐开采高粘油方法中的着火模拟实验装置流程图，图中的标记具体含义：2011：第一注入泵，2012：第二注入泵，2021：第一中间容器，2022：第二中间容器，2031：第一阀门，2032：第二阀门，204：收集阀门，205：高温箱，206：加热盘管，207：回压阀，208：可视燃烧釜，209：火焰燃烧室，210：视窗，211：压力表；212：空气气瓶，213：氧气气瓶，214：氮气气瓶，215：低粘油收集容器；Fig. 2 is the flow chart of the ignition simulation experiment device in the method for producing high-viscosity oil by huff and puff of distilled low-viscosity oil fraction according to Example 1.1, the specific meanings of the symbols in the figure: 2011: the first injection pump, 2012: the second injection pump, 2021: First Intermediate Vessel, 2022: Second Intermediate Vessel, 2031: First Valve, 2032: Second Valve, 204: Collection Valve, 205: High Temperature Box, 206: Heating Coil, 207: Back Pressure Valve, 208: Visual combustion kettle, 209: flame combustion chamber, 210: window, 211: pressure gauge; 212: air cylinder, 213: oxygen cylinder, 214: nitrogen cylinder, 215: low-viscosity oil collection container;
图3是按照实施例2.1的利用蒸馏低粘油馏分吞吐开采部署水平井的厚层超稠油油藏模型 图；Fig. 3 is a thick layer super-heavy oil reservoir model diagram of deploying horizontal wells by utilizing distilled low-viscosity oil fraction huff and puff production according to Example 2.1;
图4是按照实施例2.1的利用蒸馏低粘油馏分+二氧化碳吞吐10周期注入结束时油藏原油粘度分布图；Fig. 4 is the viscosity distribution diagram of oil reservoir crude oil at the end of 10 cycles of injection using distillation low-viscosity oil fraction + carbon dioxide huff and puff according to Example 2.1;
图5是按照实施例2.2的利用蒸馏低粘油馏分和氮气吞吐开采部署水平井的中深层厚层普通稠油油藏数值模拟预测的单井日采油和日采水动态曲线；Fig. 5 is the single well daily oil production and daily water production dynamic curve predicted by numerical simulation of the middle-deep thick layer ordinary heavy oil reservoir in which the horizontal well is exploited by utilizing distilled low-viscosity oil fraction and nitrogen huff and puff according to embodiment 2.2;
图6是为了对比实施例2.2的利用蒸馏低粘油馏分和氮气吞吐的蒸汽吞吐(注采周期8个月)开采部署水平井的中深层厚层普通稠油油藏数值模拟预测的单井日采油和日采水动态曲线；Fig. 6 is the single well day predicted by the numerical simulation of the medium-deep thick ordinary heavy oil reservoir in which the horizontal well is deployed in order to compare the steam huff and puff (injection and production period of 8 months) of the distilled low-viscosity oil fraction and nitrogen huff and puff (injection and production period of 8 months) of Example 2.2 Oil production and daily water production dynamic curves;
图7是按照实施例3.2利用蒸馏低粘油馏分吞吐开采部署直井的厚层超稠油油藏的模型结构图；Fig. 7 is a model structure diagram of a thick-layer super-heavy oil reservoir deploying vertical wells by utilizing distilled low-viscosity oil fraction huff and puff production according to Example 3.2;
图8是按照实施例4.1的利用蒸馏低粘油馏分吞吐开采厚层边底水普通稠油油藏的模型图；Fig. 8 is the model diagram of utilizing distillation low-viscosity oil fraction huff and puff to exploit thick layer edge bottom water common heavy oil reservoir according to embodiment 4.1;
图9是按照实施例4.1的利用蒸馏低粘油馏分吞吐开采厚层边底水普通稠油油藏的剖面图；Fig. 9 is the sectional view of utilizing distillation low-viscosity oil fraction huff and puff to exploit common heavy oil reservoir with thick edge and bottom water according to embodiment 4.1;
图10是按照实施例4.2的利用蒸馏低粘油馏分吞吐开采薄层边底水普通稠油油藏的模型图；Fig. 10 is the model diagram of utilizing distillation low-viscosity oil fraction huff and puff to exploit thin-layer edge-bottom water common heavy oil reservoir according to Example 4.2;
图11是按照实施例4.2的利用蒸馏低粘油馏分吞吐开采薄层边底水普通稠油油藏的剖面图。Fig. 11 is a cross-sectional view of a common heavy oil reservoir with thin edge and bottom water produced by huff and puff of distilled low-viscosity oil fraction according to Example 4.2.
具体实施方式Detailed ways
为了对本发明的技术特征、目的和有益效果有更加清楚的理解，现对本发明/的技术方案进行以下详细说明，但不能理解为对本发明的可实施范围的限定。In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the present invention/technical solutions are described in detail below, but should not be construed as limiting the scope of implementation of the present invention.
实施例1.1Example 1.1
在本实施例中，采用利用现场就地蒸馏低粘油馏分吞吐开采高粘油方法通过就地蒸馏得到低粘油并确定低粘油的安全注入温度。In the present embodiment, the low-viscosity oil is obtained by in-situ distillation and the safe injection temperature of the low-viscosity oil is determined by adopting the method of huffing and puffing low-viscosity oil fractions by on-site distillation.
参考图1，油井3穿过上覆岩层2通入油层1，将油井3采出的高粘油通过高粘油管线4通过泵5注入沉降罐6进行一次脱水和脱砂处理；经过一次脱水和脱砂处理后的高粘油再通过泵注入脱水脱盐处理罐7进行深度脱水和脱盐处理，将高粘油脱水至5％以下，脱水脱盐处理罐7产生的盐水通过盐水管线8排出；将脱水脱盐处理后的高粘油通过泵经过脱水脱盐处理后高粘油管线9注入常压加热炉10，将高粘油加热至350℃-360℃后进入常压蒸馏塔11进行常压蒸馏得到轻质馏分和重质馏分，其中，轻质馏分通过轻质馏分管线12进入高温低粘油管线18然后进入脱水脱盐处理罐7进行换热，将重质馏分通过重质馏分13通过泵注入减压加热炉14，将高粘油加热至350℃-370℃后进入减压塔15进行减压蒸馏得到中间馏分和减压渣油，最终得到轻质馏分、中间馏分和重质渣油三种馏分，其中，中间馏分通过中间馏分管线16进入高温低粘油管线18然后进入脱水脱盐处理罐7进行换热，重质渣油通过减压渣油管线17经过换热后外输或作为现场蒸馏加热等的燃料，轻质馏分、中间馏分或者二者按照一定比例混合可作为开采用高温低粘油通过高温低粘油管线18注入油井，并经过脱水脱盐处理罐7和沉降罐6内部换热降温后通过降温后低粘油管线19进入缓存罐20，缓存罐20中的低粘油可通过泵注入高粘油生产井21，高温低粘油形成注入地层中的低粘油作用区域24进行高粘油开采，同时，可以将氮气等气体或者其他介质可以通过其他介质管线22注入高粘油生产井21形成气体作用区域23，辅助高温低粘油开采地下的高粘油。Referring to Fig. 1, oil well 3 passes through overlying rock layer 2 into oil layer 1, and the high-viscosity oil produced by oil well 3 is injected into sedimentation tank 6 through high-viscosity oil pipeline 4 through pump 5 for a dehydration and desanding treatment; And the high-viscosity oil after the desanding treatment is injected into the dehydration and desalination treatment tank 7 through a pump for deep dehydration and desalination treatment, the high-viscosity oil is dehydrated to less than 5%, and the brine produced by the dehydration and desalination treatment tank 7 is discharged through the brine pipeline 8; The high-viscosity oil after dehydration and desalination is injected into the atmospheric pressure heating furnace 10 after the high-viscosity oil is dehydrated and desalted by the pump, and the high-viscosity oil is heated to 350°C-360°C and then enters the atmospheric distillation tower 11 for atmospheric distillation. Light distillate and heavy distillate, wherein the light distillate enters the high temperature and low viscosity oil pipeline 18 through the light distillate line 12 and then enters the dehydration and desalting treatment tank 7 for heat exchange, and the heavy distillate passes through the heavy distillate 13. Pressure heating furnace 14, heat the high viscosity oil to 350°C-370°C and then enter vacuum tower 15 for vacuum distillation to obtain middle distillate and vacuum residue, and finally obtain three kinds of light distillate, middle distillate and heavy residue Distillate, wherein, the middle distillate enters the high temperature and low viscosity oil pipeline 18 through the middle distillate pipeline 16 and then enters the dehydration and desalination treatment tank 7 for heat exchange, and the heavy residual oil passes through the vacuum residual oil pipeline 17 after heat exchange and is exported or used as on-site distillation. Fuels such as heating, light distillate, middle distillate or a mixture of the two in a certain proportion can be used as a high-temperature and low-viscosity oil to inject into the oil well through the high-temperature and low-viscosity oil pipeline 18, and pass through the dehydration and desalination treatment tank 7 and the internal heat exchange of the settling tank 6. After cooling down, the low-viscosity oil pipeline 19 enters the buffer tank 20. The low-viscosity oil in the buffer tank 20 can be injected into the high-viscosity oil production well 21 through a pump, and the high-temperature and low-viscosity oil forms a low-viscosity oil action area 24 injected into the formation. For high-viscosity oil production, at the same time, gas such as nitrogen gas or other medium can be injected into the high-viscosity oil production well 21 through other medium pipelines 22 to form a gas action area 23 to assist the high-temperature and low-viscosity oil extraction underground high-viscosity oil.
低粘油安全注入温度是本发明利用蒸馏低粘油馏分吞吐开采高粘油的关键参数，本实施例采用某油田高粘油进行模拟350℃常压蒸馏和减压蒸馏实验，得到轻质馏分和中间馏分，并按 《原油评价方法》(1994年版)中的ASTMD-2892/92和ASTMD-5236-92记载的方法，分别将轻质馏分和中间馏分进行常规蒸馏实验，得到不同沸点范围内馏分含量，结果如表1所示。进而，根据不同沸点馏分的含量和大气压下的着火温度，可估算蒸馏所得的轻质馏分和中间馏分在大气压下的着火温度分别为291℃和201℃，轻质馏分和中间馏分按1：1比例混合时在大气压下的着火温度估算为246℃。The safe injection temperature of low-viscosity oil is a key parameter for the invention to utilize the distillation of low-viscosity oil fractions to huff and puff to exploit high-viscosity oil. In this example, a high-viscosity oil from a certain oilfield is used to simulate 350°C atmospheric distillation and vacuum distillation experiments to obtain light fractions. and middle distillate, and according to the methods recorded in ASTMD-2892/92 and ASTMD-5236-92 in "Crude Oil Evaluation Method" (1994 edition), the light distillate and middle distillate were subjected to conventional distillation experiments respectively, and obtained different boiling point ranges. Distillate content, the results are shown in Table 1. Furthermore, according to the content of fractions with different boiling points and the ignition temperature under atmospheric pressure, the ignition temperatures of the light fraction and middle fraction obtained by distillation under atmospheric pressure can be estimated to be 291°C and 201°C, respectively, and the light fraction and middle fraction are 1:1. Ignition temperature at atmospheric pressure was estimated to be 246°C when proportionally mixed.
本实施例的着火模拟实验采用图2所示的着火模拟实验装置进行，该着火模拟实验装置至少包括：第一注入泵2011、第一中间容器2021、第一阀门2031、第二注入泵2012、第二中间容器2022、第二阀门2032、收集阀门204、高温箱205、加热盘管206、回压阀207、可视燃烧釜208(设有火焰燃烧室209、视窗210)、压力表211、空气气瓶202、氧气气瓶213、氮气气瓶214、低粘油收集容器215；其中，第一注入泵2011通过管线与第一中间容器2021的底部相连，第一中间容器2021的上部出口通过管线(设有第一阀门2031)与高温箱205中的加热盘管206的入口相连，第二注入泵2021通过管线与第二中间容器2022的底部相连，第二中间容器2022的上部出口通过管线(设有第二阀门2032)与高温箱205中的加热盘管206的入口相连；加热盘管206的出口通过管线与回压阀207相连，回压阀207通过管线与可视燃烧釜208相连，可视燃烧釜208的上部通过管线与空气气瓶212、氧气气瓶213和氮气气瓶214分别相连，管线上安装有压力表211，可视燃烧釜208的下部通过管线与低粘油收集容器215相连。The ignition simulation experiment of this embodiment is carried out by using the ignition simulation experiment device shown in FIG. 2 . The ignition simulation experiment device at least includes: a first injection pump 2011 , a first intermediate container 2021 , a first valve 2031 , a second injection pump 2012 , The second intermediate container 2022, the second valve 2032, the collection valve 204, the high temperature box 205, the heating coil 206, the back pressure valve 207, the visual combustion kettle 208 (with the flame combustion chamber 209, the window 210), the pressure gauge 211, Air cylinder 202, oxygen cylinder 213, nitrogen cylinder 214, and low-viscosity oil collection container 215; wherein, the first injection pump 2011 is connected to the bottom of the first intermediate container 2021 through a pipeline, and the upper outlet of the first intermediate container 2021 passes through The pipeline (with the first valve 2031) is connected to the inlet of the heating coil 206 in the high temperature box 205, the second injection pump 2021 is connected to the bottom of the second intermediate container 2022 through the pipeline, and the upper outlet of the second intermediate container 2022 is connected through the pipeline (with the second valve 2032) is connected to the inlet of the heating coil 206 in the high temperature box 205; the outlet of the heating coil 206 is connected to the back pressure valve 207 through a pipeline, and the back pressure valve 207 is connected to the visual combustion kettle 208 through a pipeline , the upper part of the visible combustion kettle 208 is connected to the air cylinder 212, the oxygen cylinder 213 and the nitrogen cylinder 214 respectively through pipelines, a pressure gauge 211 is installed on the pipeline, and the lower part of the visible combustion kettle 208 is collected through pipelines with low viscosity oil The container 215 is connected.
本实施例采用上述着火模拟实验装置进行轻质馏分、中间馏分、低粘油(轻质馏分和中间馏分按1：1比例的混合物)及其与氮气混合物的着火温度测试实验，着火温度测试时回压阀207压力控制在10MPa，可视燃烧釜208内的压力为大气压，气体为空气，第一批实验时，轻质馏分着火测试温度(即高温箱温度)分别设定为301℃、291℃和281℃，中间馏分着火测试温度分别设定为191℃、201℃和211℃，低粘油着火测试温度分别设定为236℃、246℃和256℃。通过可视燃烧釜208的视窗210观察管线出口高温低粘油的着火情况。In this example, the above-mentioned ignition simulation experimental device is used to test the ignition temperature of light fraction, middle fraction, low-viscosity oil (a mixture of light fraction and middle fraction in a ratio of 1:1) and their mixture with nitrogen. The pressure of the back pressure valve 207 is controlled at 10MPa, and the pressure in the combustion kettle 208 can be seen as atmospheric pressure, and the gas is air. During the first batch of experiments, the light fraction ignition test temperature (ie the temperature of the high temperature box) was set to 301°C, 291°C, respectively. ℃ and 281 ℃, the ignition test temperature of middle distillate was set to 191 ℃, 201 ℃ and 211 ℃, respectively, and the ignition test temperature of low-viscosity oil was set to 236 ℃, 246 ℃ and 256 ℃, respectively. The ignition condition of the high temperature and low viscosity oil at the outlet of the pipeline is observed through the window 210 of the visual combustion kettle 208 .
轻质馏分着火模拟实验结果如表2所示，第一批实验测试均未发现着火现象；第二批实验提高实验温度为340℃、350℃和360℃，发现350℃和360℃均观察到着火现象；第三批实验时实验温度由350℃每次降1℃进行实验，发现347℃为最低着火温度，重复试验2次均为347℃，因此，轻质馏分最低着火温度为347℃。The results of the light fraction ignition simulation experiment are shown in Table 2. No ignition was found in the first batch of experimental tests; in the second batch of experiments, the experimental temperature was increased to 340 °C, 350 °C and 360 °C, and it was found that 350 °C and 360 °C were observed. Fire phenomenon; in the third batch of experiments, the experimental temperature was lowered from 350 °C by 1 °C each time, and it was found that 347 °C was the lowest ignition temperature, and the test was repeated twice, both at 347 °C. Therefore, the minimum ignition temperature of light fractions was 347 °C.
采用与轻质馏分着火模拟实验同样的方法，测得中间馏分最低着火温度为194℃，轻质馏分和中间馏分按1：1比例的混合物最低着火温度为230℃。Using the same method as the light distillate ignition simulation experiment, the lowest ignition temperature of the middle distillate was measured to be 194 °C, and the minimum ignition temperature of the mixture of light distillate and middle distillate in a ratio of 1:1 was 230 °C.
表1某油田高粘油模拟蒸馏所得轻质馏分和中间馏分的蒸馏实验结果Table 1 Distillation experiment results of light distillate and middle distillate obtained by simulated distillation of high-viscosity oil in an oilfield
Figure PCTCN2021075005-appb-000002
Figure PCTCN2021075005-appb-000002
Figure PCTCN2021075005-appb-000003
Figure PCTCN2021075005-appb-000003
表2某油田高粘油模拟蒸馏所得轻质馏分着火模拟实验结果Table 2 The results of the ignition simulation experiment of light fractions obtained by simulated distillation of high-viscosity oil in an oilfield
Figure PCTCN2021075005-appb-000004
Figure PCTCN2021075005-appb-000004
在注入低粘油的同时注入氮气等惰性气体可提高低粘油最低着火温度，在注入氮气与低粘油(轻质馏分和中间馏分按1：1比例的混合物)的体积比分别为10、30、50和100(大气压下)时，通过所述着火模拟实验方法测得最低着火温度分别为282℃、337℃、396℃和471℃。The minimum ignition temperature of low-viscosity oil can be increased by injecting inert gas such as nitrogen while injecting low-viscosity oil. At 30, 50 and 100 (at atmospheric pressure), the minimum ignition temperatures measured by the ignition simulation experiment method were 282°C, 337°C, 396°C and 471°C, respectively.
实施例2.1Example 2.1
在本实施例中，采用现场就地蒸馏低粘油馏分吞吐开采部署水平井的厚层超稠油油藏。本实施例采用与实施例1.1类似的现场就地蒸馏过程得到可注入的低粘油，将蒸馏所得轻质组分和中间组分混合分别得到50℃粘度为150mPa·s、75mPa·s和37.5mPa·s的低粘油。In this embodiment, a thick super-heavy oil reservoir in which horizontal wells are deployed is exploited by huff and puff of in-situ distillation of low-viscosity oil fractions. In this example, the in-situ distillation process similar to Example 1.1 is used to obtain injectable low-viscosity oil, and the light components and intermediate components obtained by distillation are mixed to obtain 50°C viscosity of 150 mPa·s, 75 mPa·s and 37.5 mPa·s, respectively. mPa·s low viscosity oil.
如图3所示，一个600m×600m×30m水平、均质、厚层的稠油油藏，油藏顶深为1000m，厚度为30m，平行部署3口水平井，水平井长度均为400m，均部署在距离油层底部3.5m的位置，具体油藏参数见表3。建立了60×30×30个网格的均质油藏地质模型，网格X方向大小为5m，网格Y方向大小为20m，网格Z方向大小为1m。As shown in Figure 3, a 600m×600m×30m horizontal, homogeneous, thick-layered heavy oil reservoir with a top depth of 1000m and a thickness of 30m has three horizontal wells deployed in parallel. It is deployed at a position of 3.5m from the bottom of the oil layer. The specific reservoir parameters are shown in Table 3. A homogeneous oil reservoir geological model with 60×30×30 grids was established. The grid size in the X direction is 5m, the grid size in the Y direction is 20m, and the grid size in the Z direction is 1m.
表3超稠油油藏地质参数Table 3 Geological parameters of ultra-heavy oil reservoirs
项目project 值value
油藏模型长度(m)Reservoir model length (m) 600600
油藏模型宽度(m)Reservoir model width (m) 600600
油藏模型厚度(m)Reservoir model thickness (m) 3030
孔隙度Porosity 0.340.34
水平渗透率(mD)Horizontal permeability (mD) 30003000
垂直渗透率(mD)Vertical permeability (mD) 24002400
稠油粘度(mPa·s，地层条件)Viscosity of heavy oil (mPa s, formation conditions) 5280052800
原始含油饱和度original oil saturation 0.6750.675
原始油藏温度(℃)Original reservoir temperature (℃) 5050
原始油藏压力(MPa)Original reservoir pressure (MPa) 1010
溶解气油比Dissolved gas to oil ratio 33
本实施例中，根据稠油粘度52800mPa·s和油藏可波及半径一般小于30m，根据本发明提供的水平井低粘油注入强度设计方法，可得首周期低粘油注入强度和低粘油最大注入强度分别为8.8m 3/m和13.6m 3/m，注入氮气与低粘油的体积比(简称为气油比)为101，计算过程如下： In this embodiment, according to the viscosity of the heavy oil of 52800 mPa·s and the swept radius of the reservoir is generally less than 30 m, according to the design method for the injection strength of the low-viscosity oil in the horizontal well provided by the present invention, the injection strength of the low-viscosity oil and the low-viscosity oil in the first cycle can be obtained. The maximum injection strengths are 8.8m 3 /m and 13.6m 3 /m, respectively, and the volume ratio of injected nitrogen to low-viscosity oil (referred to as gas-oil ratio for short) is 101. The calculation process is as follows:
首周期低粘油注入强度为：The injection strength of low viscosity oil in the first cycle is:
I ho＝[1+0.1ln(R/h)]·[12ln ln(μ)-15]＝[1+0.1ln(0.03)]·[12ln ln(52800)-15]＝8.8m 3/m I ho =[1+0.1ln(R/h)]·[12lnln(μ)-15]=[1+0.1ln(0.03)]·[12lnln(52800)-15]=8.8m 3 /m
最大低粘油注入强度为：The maximum low viscosity oil injection strength is:
I ho＝[1+0.1ln(R/h)]·[12ln ln(μ)-15]＝[1+0.1ln(30/30)]·[12ln ln(52800)-15]＝13.6m 3/m I ho =[1+0.1ln(R/h)]·[12lnln(μ)-15]=[1+0.1ln(30/30)]·[12lnln(52800)-15]=13.6m 3 /m
根据本发明提供的注入氮气与低粘油在大气压下的体积比设计方法，有：According to the design method for the volume ratio of injected nitrogen and low-viscosity oil under atmospheric pressure provided by the present invention, there are:
Figure PCTCN2021075005-appb-000005
Figure PCTCN2021075005-appb-000005
本实施例中采用现场就地蒸馏低粘油馏分吞吐开采超稠油时，共进行了10周期吞吐，每周期注采周期为0.5年，共开采5年。注入介质有高温低粘油(高温低粘油50℃粘度为150mPa·s、75mPa·s和37.5mPa·s)、高温低粘油+氮气、高温低粘油+二氧化碳，注入介质温度分别为270℃(在本实施例中注入气体与低粘油在大气压下的体积比为50-100时，最低着火温度为350℃-400℃，为了保证注入安全确定现场实际低粘油最高注入温度300℃，考虑井筒热损失后井底低粘油的温度约为270℃)，日注油量为300m 3/d。参考低粘油注入强度设计结果，前3周期的周期注低粘油量分别为3500m 3、4000m 3和4500m 3，后7周期的周期注低粘油量均为5000m 3，为了对比效果，还考虑了将注入量降低20％和增加20％两种情况。参考注入气体与低粘油在大气压下的体积比设计结果，综合考虑现场气体注入能力以及后续周期吞吐时地下存气量增加，确定注入气体与低粘油在大气压下的体积比为100。焖井时间为4天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 In this example, when the low-viscosity oil fraction huff and puff is used to distill the ultra-heavy oil in situ, a total of 10 cycles of huff and puff are carried out, and the injection-production period of each cycle is 0.5 years, and the production is 5 years in total. The injection medium includes high temperature and low viscosity oil (the viscosity of high temperature and low viscosity oil at 50℃ is 150mPa·s, 75mPa·s and 37.5mPa·s), high temperature and low viscosity oil + nitrogen, high temperature and low viscosity oil + carbon dioxide, and the injection medium temperature is 270 ℃ (In this example, when the volume ratio of injected gas and low-viscosity oil under atmospheric pressure is 50-100, the minimum ignition temperature is 350-400℃. In order to ensure the safety of injection, the actual maximum injection temperature of low-viscosity oil on site is 300℃. , the temperature of the low-viscosity oil at the bottom of the well is about 270℃ after considering the heat loss of the wellbore), and the daily oil injection rate is 300m 3 /d. Referring to the design results of low-viscosity oil injection strength, the injection volume of low-viscosity oil in the first three cycles is 3500m 3 , 4000m 3 and 4500m 3 respectively, and the injection volume of low-viscosity oil in the last seven cycles is 5000m 3 . Two cases of reducing the implant by 20% and increasing it by 20% were considered. Referring to the design results of the volume ratio of injected gas and low-viscosity oil under atmospheric pressure, and taking into account the on-site gas injection capacity and the increase in underground gas storage during subsequent cycles of huff and puff, the volume ratio of injected gas and low-viscosity oil at atmospheric pressure was determined to be 100. The soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
为了对比效果，还进行了10周期蒸汽吞吐开采，每周期注采周期为0.5年，共开采5年。注汽温度为344℃；注汽干度为0.3；第1周期注汽速度为200m 3/d，第2周期后注汽速度均为300m 3/d；前3周期的周期注汽量依次为3000m 3、4500m 3和6000m 3，后7周期的周期注汽量均为7500m 3。焖井时间为4天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 In order to compare the effect, 10 cycles of steam huff and puff were also carried out, and the injection and production cycle of each cycle was 0.5 years, for a total of 5 years of mining. The steam injection temperature is 344℃; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the steam injection volume of the first three cycles is For 3000m 3 , 4500m 3 and 6000m 3 , the periodic steam injection volume of the last seven cycles is 7500m 3 . The soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
采用CMG公司的STARS热采模拟器进行油藏数值模拟，厚层超稠油油藏不同方式吞吐开采5年数值模拟计算的单井注采参数计算结果见表4。可见，仅注入270℃、150mPa·s低粘油吞吐开采10周期的累采油量(去除注入低粘油量后的净采油量)为蒸汽吞吐的73.3％，但采出水量仅为蒸汽吞吐6.2％。注入270℃、150mPa·s低粘油+氮气(气油比100)或者二氧化碳吞吐(气油比100)的累采油量与蒸汽吞吐接近，分别达到蒸汽吞吐的93.1％和99.5％。将注入气体与低粘油的体积比提高至200时，注入270℃、150mPa·s低粘油和二氧化碳进行吞吐的累采油量明显增加，达到蒸汽吞吐的1.17倍。因此，采用本发明的现场就地蒸馏的低粘油进行吞吐开采超稠油时，采油效果可以达到或超过常规蒸汽吞吐，且不需注水或蒸汽，开采10周期累采水量仅为蒸汽吞吐的6.2％-14.1％，且消除了地面锅炉用水处理过程，并且脱水处理量大大降低。 考虑到注入氮气或二氧化碳的成本而注入低粘油的量只是蒸汽吞吐注汽量的71％，估算采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采超稠油的成本可降至蒸汽吞吐1/2左右。The STARS thermal recovery simulator of CMG company was used to carry out the reservoir numerical simulation. It can be seen that the cumulative oil recovery (net oil recovery after low-viscosity oil injection is removed) for 10 cycles of huff and puff with low viscosity oil injected at 270°C and 150 mPa·s is 73.3% of that of steam huff and puff, but the produced water is only 6.2% of steam huff and puff. %. The cumulative oil recovery of low-viscosity oil injected at 270°C and 150mPa·s + nitrogen (gas-oil ratio 100) or carbon dioxide huff and puff (gas-oil ratio 100) is close to that of steam huff and puff, reaching 93.1% and 99.5% of steam huff and puff, respectively. When the volume ratio of injected gas to low-viscosity oil was increased to 200, the cumulative oil recovery by injecting low-viscosity oil and carbon dioxide at 270 °C, 150 mPa·s and carbon dioxide increased significantly, reaching 1.17 times that of steam huff and puff. Therefore, when the low-viscosity oil of the present invention is used for huff and puff recovery of super heavy oil, the oil recovery effect can reach or exceed the conventional steam huff and puff, and no water injection or steam is required, and the cumulative water production in 10 cycles of production is only 10% of the steam huff and puff. 6.2%-14.1%, and the water treatment process of the ground boiler is eliminated, and the dehydration treatment capacity is greatly reduced. Taking into account the cost of injecting nitrogen or carbon dioxide and the amount of low-viscosity oil injected is only 71% of the steam injection amount of steam stimulation, it is estimated that the cost of producing super-heavy oil by utilizing on-site distillation of low-viscosity oil fractions in the present invention can be reduced to steam. Throughput about 1/2.
表4中将低粘油注入强度提高或降低20％进行低粘油吞吐与根据本发明提供低粘油注入强度设计方法确定的低粘油注入强度方案相比，开采10周期的累采油均有所降低，原因在于注入偏低时波及范围会减少，而注入偏高时回采低粘油用时过长、地层温度降低，影响周期开采效果。因此，采用本发明的现场就地蒸馏高温低粘油吞吐开采工艺时需要采用合理的低粘油注入强度。同时，表明本发明提供的低粘油注入强度设计方法是可靠的。Compared with the low-viscosity oil injection strength scheme determined by the low-viscosity oil injection strength design method provided according to the present invention, the cumulative oil recovery of 10 cycles of production has all The reason for the decrease is that the swept range will be reduced when the injection is low, while the recovery of low-viscosity oil will take too long when the injection is high, and the formation temperature will decrease, which will affect the periodic production effect. Therefore, a reasonable injection strength of low-viscosity oil needs to be adopted when adopting the on-site in-situ distillation high-temperature low-viscosity oil huff and puff production process of the present invention. At the same time, it shows that the low-viscosity oil injection strength design method provided by the present invention is reliable.
表4厚层超稠油油藏不同方式开采5年数值模拟计算的单井注采参数Table 4. Single-well injection-production parameters calculated by numerical simulation for 5 years of different production methods in thick super-heavy oil reservoirs
Figure PCTCN2021075005-appb-000006
Figure PCTCN2021075005-appb-000006
将注入低粘油温度降至200℃时，提高注入低粘油中轻质馏分含量使其50℃粘度为75mPa·s，注入高温低粘油+二氧化碳(气油比100)吞吐10周期累采油要高于蒸汽吞吐。将注入低粘油温度降至150℃时，提高注入低粘油中轻质馏分含量使其50℃粘度为37.5mPa·s，注入高温低粘油+二氧化碳(气油比100)吞吐10周期累采油接近蒸汽吞吐。When the temperature of the injected low-viscosity oil was lowered to 200℃, the content of light distillate in the injected low-viscosity oil was increased to make the viscosity at 50℃ to 75mPa·s, and the high-temperature low-viscosity oil + carbon dioxide (gas-oil ratio 100) was injected for 10 cycles of cumulative oil recovery. higher than steam huff and puff. When the temperature of the injected low-viscosity oil was lowered to 150 °C, the content of light distillate in the injected low-viscosity oil was increased to make the viscosity at 50 °C 37.5 mPa·s, and the high-temperature low-viscosity oil + carbon dioxide (gas-oil ratio 100) was injected for 10 cycles. Oil production is close to steam huff and puff.
注入270℃、150mPa·s的低粘油+二氧化碳吞吐(气油比100)10周期注入结束时油藏原油粘度分布剖面如图4所示。可见，由于注入的高温低粘油和CO 2的作用使近井20m范围内原油粘度降至1500mPa·s，而近井10m范围内原油粘度可低至200mPa·s以下。本实施例中，高温低粘油(150mPa·s)+二氧化碳吞吐(气油比100)周期内采出油粘度逐渐升高，吞吐周期增加时采出油粘度逐渐降低。第1周期结束时采出油粘度最高，井底采出油粘度为3800mPa·s。第10周期结束时采出油井底粘度仅为200mPa·s左右。可见，采用注低粘油或者低粘油与气体组合进行吞吐开采超稠油时采出油粘度大大降低，甚至可以消除井筒掺稀和伴热。另外，随着现场就地蒸馏低粘油馏分进行吞吐周期的增加，超稠油经注入低粘油稀释后采出经蒸馏所得低粘油的粘度逐渐降低，增产效果将逐渐增强。 Figure 4 shows the oil viscosity distribution profile of the reservoir at the end of 10 cycles of low-viscosity oil injected at 270 °C and 150 mPa·s + CO2 huff and puff (gas-oil ratio 100). It can be seen that due to the action of injected high temperature and low viscosity oil and CO 2 , the viscosity of crude oil within 20m near the wellbore is reduced to 1500mPa·s, while the viscosity of crude oil within 10m near the wellbore can be as low as below 200mPa·s. In this embodiment, the viscosity of the produced oil gradually increases during the cycle of high temperature and low viscosity oil (150 mPa·s) + carbon dioxide huff and puff (gas-oil ratio 100), and the viscosity of the produced oil gradually decreases when the huff and puff cycle increases. At the end of the first cycle, the viscosity of the produced oil was the highest, and the viscosity of the produced oil at the bottom hole was 3800 mPa·s. At the end of the tenth cycle, the bottom-hole viscosity of the produced oil is only about 200 mPa·s. It can be seen that the viscosity of the produced oil is greatly reduced when the low-viscosity oil or the combination of low-viscosity oil and gas is used for huff and puff production of super-heavy oil, and even wellbore dilution and heat tracing can be eliminated. In addition, with the increase of the huff and puff cycle of on-site distillation of low-viscosity oil fractions, the viscosity of the low-viscosity oil obtained by distillation after the ultra-heavy oil is diluted by injection into the low-viscosity oil gradually decreases, and the production increase effect will gradually increase.
由本实施例的利用现场就地蒸馏低粘油馏分吞吐开采超稠油油藏的数值模拟可知：基于本 发明的利用现场就地蒸馏低粘油馏分吞吐开采高粘油方法，将高温低粘油或其与氮气/二氧化碳注入超稠油油藏进行吞吐开采，通过高温低粘油和气体的作用可使近井20m范围内的稠油粘度明显降低，油井产量明显提高，可达到或超过常规蒸汽吞吐的产量。通过提高吞吐注入气体和低粘油的气油比、提高温度、优化低粘油组成及注入强度均可提高开采超稠油的效果。当注入低粘油温度较低时，为了保证开采效果，应提高蒸馏产出低粘油中的轻质组分含量，降低注入低粘油的粘度，进而，提高低粘油对地下超稠油的稀释降粘效果和波及范围。It can be seen from the numerical simulation of utilizing on-site in-situ distillation of low-viscosity oil fractions to huff and puff to exploit super-heavy oil reservoirs in the present embodiment: based on the method of utilizing on-site in-situ distillation of low-viscosity oil fractions to huff and puff to exploit high-viscosity oil of the present invention, the high-temperature low-viscosity oil Or it can be combined with nitrogen/carbon dioxide injection into super heavy oil reservoirs for huff and puff production. Through the action of high temperature and low viscosity oil and gas, the viscosity of heavy oil within 20m near the well can be significantly reduced, and the production of oil wells can be significantly improved, which can reach or exceed conventional steam. throughput output. The effect of super-heavy oil recovery can be improved by increasing the gas-oil ratio of huff and puff injection gas and low-viscosity oil, increasing the temperature, optimizing the composition and injection strength of low-viscosity oil. When the injection temperature of low-viscosity oil is low, in order to ensure the recovery effect, the content of light components in the low-viscosity oil produced by distillation should be increased, and the viscosity of the injected low-viscosity oil should be reduced. The dilution and viscosity reduction effect and spread range.
本实施例中，注入150℃、37.5mPa·s(50℃)高温低粘油+CO 2吞吐开采超稠油不同周期时的井底温度和原油粘度如表5所示，在周期内随着开采时间延长而逐渐增大，随着吞吐周期增加而逐渐减小。地层粘度为52800mPa·s的超稠油经过热油+CO 2吞吐后周期末原油粘度降为4821.7-107.4mPa·s(普通稠油粘度水平)。降低注入低粘油粘度和缩短吞吐周期时间，可将采出油粘度降至1000-2000mPa·s以下，可以实现消除井筒举升时的掺稀和伴热工艺而降低采油成本。 In this example, the bottom hole temperature and crude oil viscosity during different periods of injection of 150°C, 37.5mPa·s (50°C) high-temperature and low-viscosity oil + CO 2 huff and puff for ultra-heavy oil production are shown in Table 5. The mining time increases gradually and gradually decreases with the increase of the throughput period. The super-heavy oil with the formation viscosity of 52800mPa·s after hot oil+CO 2 huff and puff reduces the crude oil viscosity to 4821.7-107.4mPa·s at the end of the cycle (the viscosity level of ordinary heavy oil). By reducing the viscosity of injected low-viscosity oil and shortening the cycle time of huff and puff, the viscosity of produced oil can be reduced to below 1000-2000 mPa·s, which can eliminate the dilution and heat tracing process during wellbore lifting and reduce the cost of oil production.
本实施例中，针对部署水平井的厚层超稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时，注入低粘油的粘度可为5mPa·s-500mPa·s(50℃)，注入温度可为100℃-300℃，由于超稠油的粘度对温度敏感，前几周期吞吐开采时尽可能提高注入温度，后续周期时由于地下稠油粘度变低，可适当降低注入温度。低粘油注入强度可为10m 3/m油层-15m 3/m油层，具体可参考本发明提供的方法通过计算来确定，注入气体可为天然气、氮气、二氧化碳、烟道气等气体，气体注入量与低粘油注入量在大气压下体积比为50-100，注入方式可为混合注入或者后续段塞注入。注采周期可为3-12个月。注入低粘油和气体后的焖井时间可为1-10天。 In this embodiment, for a thick super-heavy oil reservoir where horizontal wells are deployed, the viscosity of the injected low-viscosity oil can be 5mPa·s-500mPa·s when the low-viscosity oil fraction is recovered by huff and puff of the present invention. (50℃), the injection temperature can be 100℃-300℃. Since the viscosity of super heavy oil is sensitive to temperature, the injection temperature should be increased as much as possible in the first few cycles of huff and puff production. Lower the injection temperature. The injection strength of low-viscosity oil can be 10m 3 /m oil layer-15m 3 /m oil layer, which can be determined by calculation with reference to the method provided by the present invention. The injected gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases. The volume ratio of the amount to the injection amount of low-viscosity oil is 50-100 at atmospheric pressure, and the injection method can be mixed injection or subsequent slug injection. The injection period can be 3-12 months. The soaking time after injection of low viscosity oil and gas can be 1-10 days.
表5注入150℃、37.5mPa·s(50℃)低粘油+CO 2吞吐开采超稠油不同周期的井底温度和原油粘度 Table 5. Bottom hole temperature and crude oil viscosity in different periods of injection of 150℃, 37.5mPa s (50℃) low viscosity oil + CO2 huff and puff to recover super heavy oil
Figure PCTCN2021075005-appb-000007
Figure PCTCN2021075005-appb-000007
实施例2.2Example 2.2
本实施例通过利用现场就地蒸馏低粘油馏分吞吐开采部署水平井的厚层普通稠油油藏。The present embodiment utilizes in-situ in-situ distillation of low-viscosity oil fractions to huff and puff out a thick-layer common heavy oil reservoir where horizontal wells are deployed.
本实施例中，采用与实施例1.1类似的现场就地蒸馏过程得到可注入的低粘油，通过不同比例混合得到三种粘度级别的低粘油，50℃时粘度分别为37.5mPa·s、75mPa·s和100mPa·s。In this example, the in-situ distillation process similar to Example 1.1 was used to obtain injectable low-viscosity oil, and three types of low-viscosity oils were obtained by mixing in different proportions. 75mPa·s and 100mPa·s.
开采的油藏模型同实施例2.1，不同之处在于：稠油为普通稠油，地层条件下稠油粘度为1500mPa·s(脱气油粘度5260mPa·s)。注入高温低粘油+氮气吞吐开采10周期，注采周期为1 年，共开采10年。为了对比效果，注入低粘油温度分别为50℃、150℃、180℃和200℃，注入低粘油50℃粘度分别为37.5mPa·s和75mPa·s。参照本发明提供的设计方法确定的合理周期低粘油注入强度为6.2-8.3m 3/m，注入气体与低粘油在大气压下的体积比为68.7。最后设计周期注入低粘油量为2000m 3-3000m 3，注入氮气与低粘油在大气压下的体积比均为66.7(考虑到现场普通注氮气设备日注入量为20000m 3，蒸馏装置满足的低粘油日注入量为300m 3)，焖井5天，生产流压2.5MPa。为了对比，也开展了10周期蒸汽吞吐开采，每周期注采周期为1年，共开采10年。注汽温度为344℃；注汽干度为0.3；第1周期注汽速度为200m 3/d，第2周期后注汽速度均为300m 3/d；前3周期的周期注汽量依次为3000m 3、4500m 3和6000m 3，后7周期的周期注汽量均为7500m 3，焖井时间为4天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 The developed reservoir model is the same as that in Example 2.1, except that the heavy oil is ordinary heavy oil, and the viscosity of the heavy oil is 1500 mPa·s (the viscosity of degassed oil is 5260 mPa·s) under formation conditions. The injection of high temperature and low viscosity oil + nitrogen huff and puff is used for 10 cycles, the injection and production cycle is 1 year, and the total production is 10 years. In order to compare the effects, the injection temperature of low-viscosity oil was 50°C, 150°C, 180°C, and 200°C, respectively, and the viscosity of injected low-viscosity oil at 50°C was 37.5 mPa·s and 75 mPa·s, respectively. The reasonable periodic low-viscosity oil injection strength determined with reference to the design method provided by the present invention is 6.2-8.3 m 3 /m, and the volume ratio of injected gas to low-viscosity oil under atmospheric pressure is 68.7. In the final design cycle, the injection volume of low-viscosity oil is 2000m 3 -3000m 3 , and the volume ratio of injected nitrogen to low-viscosity oil under atmospheric pressure is 66.7 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the distillation unit meets the low The daily injection volume of viscous oil is 300m 3 ), and the well is kept for 5 days, and the production flow pressure is 2.5MPa. For comparison, 10-cycle steam huff and puff mining has also been carried out, and the injection-production cycle of each cycle is 1 year, for a total of 10 years of mining. The steam injection temperature is 344℃; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the steam injection volume of the first three cycles is For 3000m 3 , 4500m 3 and 6000m 3 , the steam injection volume of the last 7 cycles is 7500m 3 , the soaking time is 4 days, the maximum daily fluid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
采用CMG公司的STARS热采模拟器进行油藏数值模拟，厚层普通稠油油藏不同方式吞吐开采10年数值模拟计算的单井注采参数计算结果见表6，注入低粘油和氮气吞吐(注采周期8个月)的单井日采油和日采水动态曲线见图5，蒸汽吞吐(注采周期8个月)的单井日采油和日采水动态曲线见图6。可见，普通稠油注入150℃、粘度分别为37.5mPa·s、75mPa·s和100mPa·s(50℃)的高温低粘油+氮气吞吐开采10周期的累采油量分别为105479m 3、101783m 3和98201m 3，分别为蒸汽吞吐的1.24、1.2和1.15倍，取得了显著的增产效果。同时，采水量仅为蒸汽吞吐的1/5以下。因此，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时注高温低粘油的能耗少、采水量低和成本低。 CMG's STARS thermal recovery simulator was used for reservoir numerical simulation. The calculation results of single-well injection and production parameters calculated by different methods of huff and puff production in thick layer ordinary heavy oil reservoirs for 10 years are shown in Table 6. The injection of low viscosity oil and nitrogen huff and puff The dynamic curves of daily oil production and daily water production of a single well (injection and production period of 8 months) are shown in Figure 5, and the dynamic curves of daily oil production and daily water production of a single well with steam huff and puff (injection and production period of 8 months) are shown in Figure 6. It can be seen that the cumulative oil production of 10 cycles of high temperature and low viscosity oil + nitrogen huff and puff production at 150°C and viscosity of 37.5mPa·s, 75mPa·s and 100mPa·s (50°C), respectively, is 105479m 3 and 101783m 3 , respectively. and 98201m 3 , which are 1.24, 1.2 and 1.15 times of the steam huff and puff respectively, and have achieved a significant increase in production. At the same time, the water production is only less than 1/5 of the steam huff and puff. Therefore, when the low-viscosity oil fraction is distilled in-situ by the method of the present invention, the high-temperature and low-viscosity oil is injected with low energy consumption, low water production and low cost during huff and puff production.
表6厚层普通稠油油藏不同方式开采10年数值模拟计算的单井注采参数Table 6 Single-well injection-production parameters calculated by numerical simulation of 10-year production of thick ordinary heavy oil reservoirs in different ways
Figure PCTCN2021075005-appb-000008
Figure PCTCN2021075005-appb-000008
注入50℃粘度为37.5mPa·s、温度分别为50℃、150℃、180℃和200℃的低粘油+氮气进行吞吐开采10周期的累采油量分别为99125m 3、105479m 3、106595m 3和107283m 3，分别为蒸汽吞吐的1.16、1.24、1.25和1.26倍。可见，对于粘度较低的普通稠油，注入温度较低的低粘油和氮气即可取得明显的增产效果。 The cumulative oil production of 10 cycles of huff and puff production by injecting low-viscosity oil with a viscosity of 37.5 mPa·s at 50°C and temperatures of 50°C, 150°C, 180°C and 200°C and nitrogen gas for 10 cycles is 99125m 3 , 105479m 3 , 106595m 3 and 107283m 3 , respectively 1.16, 1.24, 1.25 and 1.26 times the steam huff and puff. It can be seen that, for ordinary heavy oil with lower viscosity, the injection of low-viscosity oil with lower temperature and nitrogen can achieve obvious production increase effect.
将150℃、37.5mPa·s低粘油的周期注入量提高至5000m 3时，高温低粘油+氮气吞吐开采10周期的累采油量为109490m 3、较周期注入量为3000m 3提高了5011吨，仅提高了3.8％。可见，对于粘度较低的普通稠油，地下流动性好，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时可采用较低的低粘油注入强度，对于本实施例低粘油的注入强度可为5-10m 3/m，周期低粘 油注入量为2000m 3-4000m 3。注入的气体可为氮气、二氧化碳、天然气和烟道气等，气体注入量与低粘油注入量在大气压下的体积比可为50-100。 When the periodic injection rate of 150℃, 37.5mPa·s low-viscosity oil is increased to 5000m 3 , the cumulative oil recovery of 10 periods of high temperature and low viscosity oil + nitrogen huff and puff production is 109,490m 3 , which is 5011 tons higher than that of the period injection rate of 3,000m 3 . , an improvement of only 3.8%. It can be seen that for ordinary heavy oil with lower viscosity, the underground fluidity is good, and the low-viscosity oil can be injected with a lower injection strength when the low-viscosity oil fraction of the present invention is used for huff and puff production. The injection strength of the oil can be 5-10m 3 /m, and the periodic low-viscosity oil injection volume is 2000m 3 -4000m 3 . The injected gas can be nitrogen, carbon dioxide, natural gas, flue gas, etc., and the volume ratio of the gas injection amount to the low-viscosity oil injection amount under atmospheric pressure can be 50-100.
实施例3.1Example 3.1
本实施例利用现场就地蒸馏低粘油馏分吞吐开采蒸汽吞吐中后期部署水平井的厚层超稠油油藏。This embodiment utilizes on-site in-situ distillation of low-viscosity oil fraction huff and puff to exploit thick super-heavy oil reservoirs in which horizontal wells are deployed in the middle and late stages of steam huff and puff.
本实施例中，采用与实施例1.1类似的现场就地蒸馏过程得到可注入的低粘油，50℃粘度为37.5mPa·s。In this example, an in-situ distillation process similar to that of Example 1.1 was used to obtain an injectable low-viscosity oil, and the viscosity at 50° C. was 37.5 mPa·s.
油藏模型和井部署与实施例2.1相同，分别开展了10周期和20周期蒸汽吞吐后再进行10周期高温低粘油+氮气吞吐，采油时工作制度与实施例2.1相同。蒸汽吞吐每周期注采周期为0.5年，注汽温度为344℃，注汽干度为0.3；第1周期注汽速度为200m 3/d，第2周期及后续周期的注汽速度均为300m 3/d；前3周期的周期注汽量依次为3000m 3、4500m 3和6000m 3，后7周期的周期注汽量均为7500m 3。焖井时间为4天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 The reservoir model and well deployment are the same as in Example 2.1. After 10 cycles and 20 cycles of steam huff and puff, respectively, 10 cycles of high temperature and low viscosity oil + nitrogen huff and puff were carried out. The working system during oil production was the same as in Example 2.1. The injection-production cycle of each cycle of steam huff and puff is 0.5 years, the steam injection temperature is 344°C, and the steam injection dryness is 0.3; the steam injection rate in the first cycle is 200m 3 /d, and the steam injection rate in the second and subsequent cycles is 300m. 3 /d; the steam injection volume of the first 3 cycles is 3000m 3 , 4500m 3 and 6000m 3 in turn, and the cycle steam injection volume of the last 7 cycles is 7500m 3 . The soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
本实施例中，蒸汽吞吐10周期或20周期后采用本发明的利用现场就地蒸馏低粘油馏分进行吞吐开采，为了提高开采效果，在注入低粘油馏分的同时注入氮气，进行10周期吞吐，每周期注采周期为0.5年，共开采5年。注入的低粘油粘度为37.5mPa·s(50℃)，注入低粘油的温度为150℃-300℃。根据本发明提供的水平井低粘油注入强度设计方法，可得转注低粘油吞吐的合理注入强度为8.8m 3/m-13.6m 3/m，注入氮气与低粘油的体积比为101，据此设计前2周期的周期注油量分别为3000m 3和4000m 3，后8周期的周期注油量均为5000m 3。注入氮气与低粘油在大气压下的体积比为90(考虑到现场普通注氮气设备日注入量为20000m 3，蒸馏装置满足的低粘油日注入量为300m 3，在注低粘油阶段注入氮气与低粘油的体积比为66.7，但在停注低粘油后连续注入氮气，最后注入氮气与低粘油的体积比为90)。日注油量为300m 3/d，焖井时间为5天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 In this embodiment, after 10 cycles or 20 cycles of steam huff and puff, the low-viscosity oil fraction of the present invention is used for huff and puff production. In order to improve the production effect, nitrogen is injected at the same time as the low-viscosity oil fraction is injected, and 10 cycles of huff and puff are carried out. , the injection-production cycle of each cycle is 0.5 years, a total of 5 years of mining. The viscosity of the injected low-viscosity oil is 37.5 mPa·s (50°C), and the temperature of the injected low-viscosity oil is 150°C-300°C. According to the low-viscosity oil injection strength design method for horizontal wells provided by the present invention, the reasonable injection strength of low-viscosity oil transfer injection can be obtained as 8.8m 3 /m-13.6m 3 /m, and the volume ratio of injected nitrogen to low-viscosity oil is 101 According to this, the oil injection volume of the first two cycles is 3000m 3 and 4000m 3 respectively, and the oil injection volume of the last eight cycles is 5000m 3 . The volume ratio of injected nitrogen and low-viscosity oil at atmospheric pressure is 90 (considering that the daily injection volume of the ordinary nitrogen injection equipment on site is 20,000m 3 , and the daily injection volume of the low-viscosity oil for the distillation unit is 300m 3 , the injection is performed during the low-viscosity oil injection stage. The volume ratio of nitrogen to low-viscosity oil is 66.7, but after stopping the injection of low-viscosity oil, nitrogen is continuously injected, and finally the volume ratio of nitrogen to low-viscosity oil is 90). The daily oil injection rate is 300m 3 /d, and the soaking time is 5 days. During oil production, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
采用CMG公司的STARS热采模拟器进行油藏数值模拟，针对上述超稠油油藏，开展了蒸汽吞吐中后期注高温低粘油+氮气吞吐开采数值模拟计算，预测的单井注采参数计算结果见表7。可见，超稠油油藏蒸汽吞吐10周期后注入150℃高温低粘油+N 2吞吐10周期的累采油量与蒸汽吞吐20周期的累采油量相当，150℃高温低粘油+N 2吞吐10周期的累采油量为47858.3m 3，为后10周期蒸汽吞吐累采油量的93.1％。将注入低粘油温度提高到200℃时，高温低粘油+N 2吞吐10周期的累采油量为53728.3m 3，为后10周期蒸汽吞吐累采油量的1.05倍。超稠油油藏蒸汽吞吐20周期后注入150℃高温低粘油+N 2吞吐10周期的累采油量与蒸汽吞吐30周期累采油量相当。 CMG's STARS thermal recovery simulator was used to conduct reservoir numerical simulation. For the above-mentioned ultra-heavy oil reservoirs, the numerical simulation calculation of high temperature and low viscosity oil injection + nitrogen huff and puff production in the middle and late stages of steam huff and puff was carried out, and the predicted single well injection and production parameters were calculated. The results are shown in Table 7. It can be seen that the cumulative oil recovery of 10 cycles of steam huff and puff at 150°C after injection of 150°C high temperature and low viscosity oil + N2 huff and puff is equivalent to that of 20 cycles of steam huff and puff. The cumulative oil recovery of 10 cycles is 47858.3 m 3 , which is 93.1% of the cumulative oil recovery of the next 10 cycles of steam huff and puff. When the injection temperature of low viscosity oil is increased to 200℃, the cumulative oil recovery of high temperature and low viscosity oil + N 2 huff and puff for 10 cycles is 53728.3m 3 , which is 1.05 times of the cumulative oil recovery of steam huff and puff in the next 10 cycles. After 20 cycles of steam huff and puff in the ultra-heavy oil reservoir, the cumulative oil recovery of 150℃ high temperature and low viscosity oil + N2 huff and puff for 10 cycles is equivalent to that of 30 cycles of steam huff and puff.
表7超稠油油藏蒸汽吞吐中后期注高温低粘油+氮气吞吐开采数值模拟计算的单井注采参数Table 7 Single-well injection and production parameters calculated by numerical simulation of high temperature and low viscosity oil + nitrogen huff and puff production in the middle and late stages of steam huff and puff in ultra-heavy oil reservoirs
Figure PCTCN2021075005-appb-000009
Figure PCTCN2021075005-appb-000009
Figure PCTCN2021075005-appb-000010
Figure PCTCN2021075005-appb-000010
本实施例中，针对蒸汽吞吐中后期部署水平井的厚层超稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时，注入低粘油的粘度可为5mPa·s-500mPa·s(50℃)，注入温度可为100℃-300℃，低粘油注入强度可为5m 3/m油层-15m 3/m油层，具体可参考本发明提供的方法通过计算来确定，注入气体可为天然气、氮气、二氧化碳、烟道气等气体，气体注入量与低粘油注入量在大气压下体积比为50-100，注入方式可为混合注入或者后续段塞注入。注采周期可为8-16个月。注入低粘油和气体后的焖井时间可为1-10天。 In this embodiment, for a thick super-heavy oil reservoir in which horizontal wells are deployed in the middle and late stages of steam huff and puff, the viscosity of the injected low-viscosity oil can be 5 mPa·s when the low-viscosity oil fraction is huff and puff produced by in-situ distillation of the present invention. -500mPa·s (50℃), the injection temperature can be 100℃-300℃, the injection strength of low-viscosity oil can be 5m 3 /m oil layer to 15m 3 /m oil layer, which can be determined by calculation with reference to the method provided in the present invention , the injection gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases. The volume ratio of gas injection to low-viscosity oil injection under atmospheric pressure is 50-100. The injection method can be mixed injection or subsequent slug injection. The injection period can be 8-16 months. The soaking time after injection of low viscosity oil and gas can be 1-10 days.
由本实施例中利用现场就地蒸馏低粘油馏分吞吐开采蒸汽吞吐中后期部署水平井的厚层超稠油油藏可知：对于蒸汽吞吐中后期部署水平井的厚层超稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐可达到与蒸汽吞吐相当的效果，通过降低注入低粘油粘度、提高注入低粘油温度、适当提高气油比及优化注入量还可进一步提高增产效果。较蒸汽吞吐具有明显的能耗低、采出水量低和成本低的优势。It can be seen from this example that the use of on-site distillation of low-viscosity oil fraction huff and puff to exploit the thick super-heavy oil reservoir with horizontal wells deployed in the middle and late stages of steam huff and puff shows that: The low-viscosity oil fraction huff and puff of the present invention can achieve the effect equivalent to that of steam huff and puff by on-site distillation, and can be further improved by reducing the viscosity of the injected low-viscosity oil, increasing the injection temperature of the low-viscosity oil, properly increasing the gas-oil ratio and optimizing the injection amount Yield increase effect. Compared with steam huff and puff, it has obvious advantages of low energy consumption, low produced water volume and low cost.
实施例3.2Example 3.2
本实施例中采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采蒸汽吞吐后期部署直井的超稠油油藏。In the present embodiment, the super-heavy oil reservoir in which the vertical well is deployed in the later stage is exploited by utilizing the on-site in-situ distillation of low-viscosity oil fraction huff and puff to exploit the steam huff and puff of the present invention.
本实施例中，采用与实施例1.1类似的现场就地蒸馏过程得到可注入的低粘油，50℃粘度为35mPa·s。In this example, an in-situ distillation process similar to that of Example 1.1 was used to obtain an injectable low-viscosity oil, and the viscosity at 50° C. was 35 mPa·s.
参考图7，一个深度为600m，面积为200m×200m，具有3个油层的超稠油油藏，3个油层厚度均为5m，总厚度15m，上下两个隔层厚度分别为4m和3m，3个油层自上而下孔隙度分别为0.33、0.315和0.34，渗透率分别为3000mD、2000mD和4000mD。地层条件下稠油粘度为121088mPa·s，45℃脱气油粘度为212903mPa·s。原始油层温度为45℃，原始油层压力为6MPa，原始含油饱和度0.675。油藏按正方形井网部署4口直井，井距100m，3个油层均射孔。数值模拟油藏模型共有40×40×20个网格，网格X方向和Y方向大小均为5m，网格Z方向大小为1m-2m。Referring to Figure 7, an ultra-heavy oil reservoir with a depth of 600m and an area of 200m×200m has three oil layers, each of which is 5m thick, with a total thickness of 15m. The thickness of the upper and lower layers is 4m and 3m respectively. The top-to-bottom porosity of the three oil layers is 0.33, 0.315 and 0.34, and the permeability is 3000mD, 2000mD and 4000mD, respectively. Under formation conditions, the viscosity of heavy oil is 121088mPa·s, and the viscosity of degassed oil at 45℃ is 212903mPa·s. The original oil layer temperature is 45℃, the original oil layer pressure is 6MPa, and the original oil saturation is 0.675. Four vertical wells are deployed in the reservoir according to a square well pattern, with a well spacing of 100m, and all three oil layers are perforated. The numerical simulation reservoir model has a total of 40 × 40 × 20 grids, the size of the grid in the X and Y directions is 5m, and the size of the grid in the Z direction is 1m-2m.
本实施例中利用现场就地蒸馏低粘油馏分吞吐开采蒸汽吞吐后期部署直井的超稠油油藏，首先蒸汽吞吐开采10周期，每周期注采周期为0.5年，共开采5年。单井第1周期注汽速度为200m 3/d，后续周期注汽速度均为300m 3/d。单井5周期的周期注汽量分别为1000m 3、1500m 3、1800m 3、2400m 3和3000m 3。各周期注汽温度均为344℃、注汽干度均为0.3，焖井时间均为3天，采油时单井最高日产液量50m 3/d，最低流压为0.5MPa。然后，进行注入低粘油和氮气吞吐开采10周期，每周期注采周期为0.5年，共开采5年。注入的低粘油50℃粘度为35mPa·s，注入温度为150℃，单井日注油量为200m 3/d-300m 3/d。根据本发明提供的直井低粘油注入强度设计方法，可得转注低粘油吞吐的合理注入强度为71m 3/m-118m 3/m，注入氮气与低粘油的体积比为108，据此设计单井周期低粘油注入量为1000m 3-1800m 3。焖井时间均为3天，采油时单井最 高日产液量50m 3/d，最低流压为0.5MPa。为了对比效果，还进行了20周期蒸汽吞吐开采，前10周期与上述蒸汽吞吐相同，后10周期注采周期均为0.5年，注汽温度均为344℃，注汽干度均为0.3，单井注汽速度均为300m 3/d，单井周期注汽量均为3000m 3，焖井时间为3天，采油时油井最高日产液量50m 3/d，最低流压为0.5MPa。 In this example, in-situ distillation of low-viscosity oil fraction huff and puff is used to exploit the super-heavy oil reservoir in which vertical wells are deployed in the later stage of steam huff and puff. First, the steam huff and puff is exploited for 10 cycles, and the injection-production cycle of each cycle is 0.5 years, for a total of 5 years of exploitation. The steam injection rate of the first cycle of a single well is 200m 3 /d, and the steam injection rate of the subsequent cycles is 300m 3 /d. The cyclical steam injection volume for 5 cycles of a single well is 1000m 3 , 1500m 3 , 1800m 3 , 2400m 3 and 3000m 3 respectively. In each cycle, the steam injection temperature was 344℃, the steam injection dryness was 0.3, and the well soaking time was 3 days. During oil production, the maximum daily liquid production of a single well was 50m 3 /d, and the minimum flow pressure was 0.5MPa. Then, 10 cycles of low-viscosity oil injection and nitrogen huff and puff were carried out, and the injection and production cycle of each cycle was 0.5 years, for a total of 5 years of production. The injected low-viscosity oil has a viscosity of 35 mPa·s at 50°C, an injection temperature of 150°C, and a daily oil injection rate of 200m 3 /d-300m 3 /d for a single well. According to the low-viscosity oil injection strength design method for vertical wells provided by the present invention, the reasonable injection strength of low-viscosity oil injection is 71m 3 /m-118m 3 /m, and the volume ratio of injected nitrogen gas to low-viscosity oil is 108. The designed single-well cycle low-viscosity oil injection volume is 1000m 3 -1800m 3 . The soaking time is 3 days. The maximum daily liquid production of a single well is 50 m 3 /d and the minimum flow pressure is 0.5 MPa during oil production. In order to compare the effect, 20 cycles of steam huff and puff were also carried out. The first 10 cycles were the same as the above steam huff and puff, and the last 10 cycles were all injection-production cycles of 0.5 years. The well steam injection rate is 300m 3 /d, the single well cycle steam injection volume is 3000m 3 , the well soaking time is 3 days, the maximum daily liquid production of the oil well is 50m 3 /d, and the minimum flow pressure is 0.5MPa.
采用CMG公司的STARS热采模拟器，针对上述蒸汽吞吐开采后期部署直井的超稠油油藏，开展了注入低粘油+氮气吞吐及蒸汽吞吐的数值模拟计算，预测的单井注采参数见表8。可见，对于本实施例中蒸汽吞吐开采后期部署直井的超稠油油藏，蒸汽吞吐5周期后注入150℃低粘油和氮气吞吐5周期，在单井周期注入低粘油量仅为蒸汽吞吐周期注汽量的30％的条件下，吞吐5周期去除注入低粘油量后的累积采油量为蒸汽吞吐的1.08倍，后5周期吞吐采出水量仅为蒸汽吞吐的14％。可见，本发明的利用现场就地蒸馏低粘油馏分吞吐方法注入低粘油量远低于蒸汽吞吐的注汽量，加热低粘油的燃烧消耗量远低于高温蒸汽，同时，消除了地面锅炉用水处理过程，采出液脱水处理量也大大降低。Using CMG's STARS thermal recovery simulator, numerical simulations of low-viscosity oil injection + nitrogen huff and puff and steam huff and puff were carried out for the super-heavy oil reservoirs in which vertical wells were deployed in the later stage of steam huff and puff production. The predicted single-well injection and production parameters are shown in Table 8. It can be seen that for the ultra-heavy oil reservoir in which vertical wells are deployed in the later stage of steam huff and puff production in this example, after 5 cycles of steam huff and puff, low-viscosity oil at 150 °C and 5 cycles of nitrogen huff and puff are injected, and the amount of low-viscosity oil injected in a single well cycle is only steam huff and puff. Under the condition of 30% of the periodic steam injection, the cumulative oil recovery after 5 cycles of huff and puff after the injection of low-viscosity oil is 1.08 times that of the steam huff and puff, and the water produced by the latter 5 cycles of huff and puff is only 14% of that of the steam huff and puff. It can be seen that the low-viscosity oil injected by the on-site in-situ distillation low-viscosity oil fraction huff and puff method of the present invention is much lower than the steam injection amount of the steam huff and puff, and the combustion consumption of heating the low-viscosity oil is much lower than that of the high-temperature steam. In the process of boiler water treatment, the amount of produced liquid dehydration is also greatly reduced.
表8注低粘油和氮气开采蒸汽吞吐中后期部署直井的超稠油油藏数值模拟计算的单井注采参数Table 8. Single-well injection-production parameters calculated by numerical simulation of ultra-heavy oil reservoirs with vertical wells deployed in the middle and late stages of low-viscosity oil injection and nitrogen production steam huff and puff
Figure PCTCN2021075005-appb-000011
Figure PCTCN2021075005-appb-000011
本实施例中，针对蒸汽吞吐中后期部署直井的厚层超稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时，注入低粘油的粘度可为5mPa·s-500mPa·s(50℃)，注入温度可为100℃-300℃，注入强度可为50m 3/m油层-150m 3/m油层，注入气体可为天然气、氮气、二氧化碳、烟道气等气体，气体注入量与低粘油注入量在大气压下的体积比为30-120(当蒸汽吞吐中后期井间汽窜明显时可降低注入气体的量)，注入方式可为混合注入、前置段塞或者后续段塞，注采周期可为3-12个月。注入低粘油和气体后的焖井时间可为1-10天。 In this embodiment, for a thick super-heavy oil reservoir in which vertical wells are deployed in the middle and late stages of steam huff and puff, when the low-viscosity oil fraction of the present invention is produced by huff and puff, the viscosity of the injected low-viscosity oil can be 5 mPa·s- 500mPa·s (50℃), injection temperature can be 100℃-300℃, injection intensity can be 50m 3 /m oil layer-150m 3 /m oil layer, injection gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases, The volume ratio of gas injection and low-viscosity oil injection under atmospheric pressure is 30-120 (the amount of injected gas can be reduced when steam channeling between wells is obvious in the middle and late stages of steam huff and puff), and the injection method can be mixed injection, front slug Or for subsequent slugs, the injection-production cycle can be 3-12 months. The soaking time after injection of low viscosity oil and gas can be 1-10 days.
实施例4.1Example 4.1
本实施例利用现场就地蒸馏低粘油馏分吞吐开采部署水平井的厚层边底水普通稠油油藏。This embodiment utilizes on-site in-situ distillation of low-viscosity oil fraction huff and puff to exploit the thick-layer edge-bottom water common heavy oil reservoir with horizontal wells.
本实施例中，采用与实施例1.1类似的现场就地蒸馏过程得到可注入的低粘油，50℃粘度为37.5mPa·s。In this example, an in-situ distillation process similar to that of Example 1.1 was used to obtain an injectable low-viscosity oil, and the viscosity at 50° C. was 37.5 mPa·s.
开采的油藏模型为一背斜构造边底水油藏，油藏模型结构如图8所示，油藏模型剖面如图9所示。油层深度1550m，稠油为普通稠油，地层条件下稠油粘度为4500mPa·s(脱气油50℃粘度6370mPa·s)；油层厚度为30m，油层孔隙度为0.3，渗透率为1500mD；油藏边底水体积与油区体积比为50；共部署平行的3口水平井，水平井长度为300m，井距为100m，靠近边底水的油井部署在距底部23.5m处，中间的油井和远离边底水的油井均部署在距底部13.5m处。The developed reservoir model is an anticline structural edge-bottom water reservoir, the structure of the reservoir model is shown in Figure 8, and the section of the reservoir model is shown in Figure 9. The depth of the oil layer is 1550m, the heavy oil is ordinary heavy oil, and the viscosity of the heavy oil is 4500mPa·s under formation conditions (the viscosity of the degassed oil is 6370mPa·s at 50°C); the oil layer thickness is 30m, the oil layer porosity is 0.3, and the permeability is 1500mD; The volume ratio of reservoir edge and bottom water to oil area volume is 50; a total of 3 horizontal wells are deployed in parallel, with a horizontal well length of 300m and a well spacing of 100m. Oil wells far from the edge and bottom water are deployed at a distance of 13.5m from the bottom.
为了对比效果，分别开展了基于本发明利用现场就地蒸馏低粘油馏分+氮气吞吐和蒸汽吞吐的油藏数值模拟。由于水侵的影响只开展了模拟计算期4年的模拟计算，注采周期分别为0.5年和1年。注入低粘油温度为150℃，注入低粘油50℃粘度为37.5mPa·s。根据本发明提供的直井低粘油注入强度设计方法，可得转注低粘油吞吐的合理注入强度为8.7m 3/m-12.4m 3/m，注入 氮气与低粘油的体积比为76，据此设计周期低粘油注入量为3000m 3，注入氮气与低粘油的体积比为66.7(考虑到现场普通注氮气设备日注入量为20000m 3，蒸馏装置满足的低粘油日注入量为300m 3)，焖井5天，生产流压2.5MPa。蒸汽吞吐的注汽温度为344℃；注汽干度为0.3；第1周期注汽速度为200m 3/d，第2周期后注汽速度均为300m 3/d；各周期的周期注汽量按3000m 3、4500m 3、6000m 3和7500m 3，增至7500m 3后保持不再增加。焖井时间为4天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 In order to compare the effects, numerical simulations of oil reservoirs based on the present invention using on-site distillation of low-viscosity oil fraction + nitrogen huff and puff and steam huff and puff were carried out respectively. Due to the impact of water intrusion, only the simulation calculation period of 4 years was carried out, and the injection and production periods were 0.5 years and 1 year respectively. The temperature of the injected low-viscosity oil is 150°C, and the viscosity of the injected low-viscosity oil at 50°C is 37.5 mPa·s. According to the method for designing the injection strength of low-viscosity oil in vertical wells provided by the present invention, the reasonable injection strength of low-viscosity oil transfer injection can be obtained as 8.7m 3 /m-12.4m 3 /m, and the volume ratio of injected nitrogen to low-viscosity oil is 76, According to this, the injection volume of low-viscosity oil in the design cycle is 3000m 3 , and the volume ratio of injected nitrogen gas to low-viscosity oil is 66.7 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the daily injection volume of low-viscosity oil for the distillation unit is 300m 3 ), soaking the well for 5 days, and the production flow pressure is 2.5MPa. The steam injection temperature of steam huff and puff is 344℃; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the cycle steam injection volume of each cycle According to 3000m 3 , 4500m 3 , 6000m 3 and 7500m 3 , after increasing to 7500m 3 , it will not increase. The soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
采用CMG公司的STARS热采模拟器进行油藏数值模拟，厚层边底水普通稠油油藏不同方式吞吐开采10年数值模拟计算的各井注采参数计算结果见表9。可见，在相同注采参数下，距离边底水距离依次变远的一线井、二线井和三线井由于水侵的影响开采效果差别很大。在本实施例中注入150℃、粘度为37.5mPa·s(50℃)的高温低粘油+氮气吞吐开采的累采油量与蒸汽吞吐相当，一线井的累采水量稍低于蒸汽吞吐，二线井和三线井的累采水量由于未注蒸汽而明显低于蒸汽吞吐，热耗和成本也明显低于蒸汽吞吐。由于一线井靠近边底水、容易水侵，适合采用低采油速度，本实施例中注入高温低粘油+氮气吞吐1年2周期的开采效果与1年1周期的开采效果相当，而二线井和三线井由于不容易水侵，可提高采油速度，本实施例中注入高温低粘油+氮气吞吐1年2周期的开采效果要好于1年1周期的开采效果。The STARS thermal recovery simulator of CMG company is used to simulate the reservoir numerically. The calculation results of injection and production parameters of each well calculated by different methods of huff and puff production for 10 years in the thick-layer edge-bottom water ordinary heavy oil reservoir are shown in Table 9. It can be seen that under the same injection-production parameters, the first-line wells, the second-line wells and the third-line wells whose distances from the edge and bottom water become farther in turn have great differences in the production effect due to the influence of water intrusion. In this example, the cumulative oil production of high temperature and low viscosity oil with a viscosity of 37.5 mPa·s (50 °C) at 150 °C and nitrogen huff and puff production is comparable to that of steam huff and puff. The cumulative water production of wells and third-line wells is significantly lower than that of steam huff and puff due to no steam injection, and the heat consumption and cost are also significantly lower than those of steam huff and puff. Since the first-line well is close to the water at the edge and bottom and is prone to water intrusion, it is suitable for low oil production rate. Since the Hesanxian well is not prone to water invasion, the oil production rate can be increased. In this example, the production effect of injecting high temperature and low viscosity oil + nitrogen huff and puff for 1 year and 2 cycles is better than that of 1 year and 1 cycle.
本实施例中，针对部署水平井的厚层边底水普通稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时，注入低粘油的粘度可为5mPa·s-300mPa·s(50℃)，注入温度可为100℃-300℃，低粘油注入强度可为5m 3/m油层-15m 3/m油层，具体可参考本发明提供的方法通过计算来确定，注入气体可为天然气、氮气、二氧化碳、烟道气等气体，气体注入量与低粘油注入量在大气压下的体积比为50-100，注入方式可为混合注入或者后续段塞注入。注采周期可为8-16个月。注入低粘油和气体后的焖井时间可为1-10天。 In this embodiment, for a thick oil reservoir with thick edge and bottom water in which horizontal wells are deployed, when the low-viscosity oil fraction of the present invention is produced by huff and puff, the viscosity of the injected low-viscosity oil can be 5 mPa·s- 300mPa·s (50℃), the injection temperature can be 100℃-300℃, and the injection strength of low-viscosity oil can be 5m 3 /m oil layer-15m 3 /m oil layer, which can be determined by calculation with reference to the method provided in the present invention, The injected gas can be natural gas, nitrogen, carbon dioxide, flue gas, etc. The volume ratio of gas injection to low-viscosity oil injection under atmospheric pressure is 50-100. The injection method can be mixed injection or subsequent slug injection. The injection period can be 8-16 months. The soaking time after injection of low viscosity oil and gas can be 1-10 days.
由本实施例中利用现场就地蒸馏低粘油馏分吞吐开采厚层边底水普通稠油油藏的数值模拟可知：边底水普通稠油油藏水体能量强时油井(尤其是一线井)容易发生水侵，距离边底水距离依次变远的一线井、二线井和三线井注低粘油和氮气吞吐开采效果差异大，但均可达到与蒸汽吞吐相当的采油效果，通过提高注入低粘油温度、降低注入低粘油粘度、优化注低粘油和氮气气油比等注采参数，可取得好于蒸汽吞吐的开采效果，并具有能耗低、采出水量低和成本低的优势。同时，也需要采取限液、调堵等措施来提高控水增油效果。It can be seen from the numerical simulation of the huff and puff exploitation of thick edge-bottom water common heavy oil reservoirs in this example by using on-site distillation of low-viscosity oil fractions: when the water body energy of common heavy oil reservoirs with edge-bottom water is strong, oil wells (especially first-line wells) are easy to perform. First-line wells, second-line wells and third-line wells where water intrusion occurs and the distance from edge-to-bottom water becomes farther in turn have great differences in the production effect of low-viscosity oil injection and nitrogen huff and puff, but they can all achieve the same oil production effect as steam huff and puff. Oil temperature, reducing the viscosity of injected low-viscosity oil, optimizing injection-production parameters such as low-viscosity oil injection and nitrogen gas-oil ratio can achieve better production effect than steam huff and puff, and have the advantages of low energy consumption, low produced water volume and low cost . At the same time, it is also necessary to take measures such as limiting liquid and adjusting plugging to improve the effect of water control and oil increase.
表9厚层边底水普通稠油油藏不同方式吞吐开采10年数值模拟计算的各井注采参数Table 9. Injection and production parameters of each well calculated by numerical simulation of 10-year huff and puff production in ordinary heavy oil reservoirs with thick edge and bottom water
Figure PCTCN2021075005-appb-000012
Figure PCTCN2021075005-appb-000012
Figure PCTCN2021075005-appb-000013
Figure PCTCN2021075005-appb-000013
实施例4.2Example 4.2
本实施例利用现场就地蒸馏低粘油馏分吞吐开采部署水平井的薄层边底水普通稠油油藏。In this embodiment, the thin-layer edge-bottom water common heavy oil reservoir with horizontal wells is exploited by huff and puff of on-site distillation of low-viscosity oil fractions.
本实施例中，采用与实施例1.1类似的现场就地蒸馏过程得到可注入的低粘油，通过不同比例混合得到两种粘度级别的低粘油，50℃粘度分别为37.5mPa·s和100mPa·s。In this example, the in-situ distillation process similar to Example 1.1 was used to obtain injectable low-viscosity oil, and two types of low-viscosity oils were obtained by mixing in different proportions. The viscosity at 50°C was 37.5mPa·s and 100mPa, respectively. ·s.
薄层边底水普通稠油油藏，油藏模型结构如图10所示，油藏模型剖面如图11所示。油藏模型的油层深度为1550m，油层厚度为10m，孔隙度为0.3，渗透率为1500mD，地层条件下稠油粘度为4500mPa·s(脱气油50℃粘度6370mPa·s)，油藏边底水体积与油区体积比为50。共部署平行的3口水平井，水平井长度为300m，井距为100m，靠近边底水的油井部署在距底部7.5m处，中间的油井部署在距底部5.5m处，远离边底水的油井部署在距底部2.5m处。边底水距离最近的油井距离200m。For ordinary heavy oil reservoirs with thin edge and bottom water, the structure of the reservoir model is shown in Figure 10, and the section of the reservoir model is shown in Figure 11. The oil layer depth of the reservoir model is 1550m, the oil layer thickness is 10m, the porosity is 0.3, and the permeability is 1500mD. The water volume to oil zone volume ratio was 50. A total of 3 parallel horizontal wells are deployed. The length of the horizontal wells is 300m and the well spacing is 100m. The oil wells close to the edge and bottom water are deployed at a distance of 7.5m from the bottom, and the middle oil wells are deployed at a distance of 5.5m from the bottom, away from the oil wells of the edge and bottom water. Deployed at 2.5m from the bottom. The distance between the edge and bottom water is 200m from the nearest oil well.
采用CMG公司的STARS热采模拟器，针对上述薄层边底水油藏，开展了低粘油+氮气吞吐和蒸汽吞吐油藏数值模拟，模拟计算期5年，注采周期为0.5年。注入低粘油温度为150℃、180℃和200℃，注入低粘油50℃时粘度为37.5mPa·s。根据本发明提供的水平井低粘油注入强度设计方法，可得转注低粘油吞吐的合理注入强度为9.4m 3/m-10.6m 3/m，注入氮气与低粘油的体积比为72，据此设计周期低粘油的注入量为3000m 3，注入氮气与注入低粘油的体积比为66.7(考虑到现场普通注氮气设备日注入量为20000m 3，蒸馏装置满足的低粘油日注入量为300m 3)，焖井5天，生产流压2.5MPa。蒸汽吞吐的注汽温度为344℃；注汽干度为0.3；第1周期注汽速度为200m 3/d，第2周期后注汽速度均为300m 3/d；各周期的周期注汽量按3000m 3、4500m 3、6000m 3和7500m 3递增至7500m 3后保持不再增加。焖井时间为4天，采油时油井最高日产液量100m 3/d，最低流压为2.5MPa。 Using CMG's STARS thermal recovery simulator, numerical simulations of low-viscosity oil + nitrogen huff and puff and steam huff and puff reservoirs were carried out for the above thin-layer edge-bottom water reservoirs. The simulation calculation period was 5 years, and the injection-production period was 0.5 years. The injection temperature of low-viscosity oil was 150℃, 180℃ and 200℃, and the viscosity of low-viscosity oil was 37.5mPa·s at 50℃. According to the low-viscosity oil injection strength design method for horizontal wells provided by the present invention, the reasonable injection strength of low-viscosity oil transfer can be obtained as 9.4m 3 /m-10.6m 3 /m, and the volume ratio of injected nitrogen gas to low-viscosity oil is 72 , the injection volume of low-viscosity oil in the design cycle is 3000m 3 , and the volume ratio of injected nitrogen gas to injected low-viscosity oil is 66.7 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the distillation unit meets the daily injection volume of low-viscosity oil. The injection volume was 300m 3 ), the well was simmered for 5 days, and the production flow pressure was 2.5MPa. The steam injection temperature of steam huff and puff is 344℃; the dryness of steam injection is 0.3; the steam injection speed of the first cycle is 200m 3 /d, and the steam injection speed after the second cycle is 300m 3 /d; the cycle steam injection volume of each cycle After increasing to 7500m 3 according to 3000m 3 , 4500m 3 , 6000m 3 and 7500m 3 , it will not increase. The soaking time is 4 days, the maximum daily liquid production of the oil well is 100m 3 /d, and the minimum flow pressure is 2.5MPa.
由于边底水距离油井距离较远，在5年计算期内3口井均未发生明显水侵，3口井的开采效果基本相同。薄层边底水普通稠油油藏不同方式吞吐开采10年数值模拟计算的单井注采参数计算结果见表10，可见，每周期注入3000m 3的150℃、100mPa·s(50℃)低粘油+氮气，吞吐10周期累采油量为蒸汽吞吐的93.5％，但累水量仅为蒸汽吞吐的23.1％，且低粘油+氮气吞吐时不需注入水蒸汽(蒸汽吞吐时每周期需注入3000m 3-7500m 3蒸汽)，而注氮气成本要明显低于注蒸汽，因此，在本实例中，每周期注入3000m 3的150℃、100mPa·s(50℃)低粘油+氮气吞吐的开采效果与蒸汽吞吐相当而成本则明显低于蒸汽吞吐。 Since the edge and bottom water is far away from the oil well, no obvious water intrusion occurred in the three wells during the 5-year calculation period, and the production effects of the three wells are basically the same. Table 10 shows the calculation results of single-well injection-production parameters calculated by different methods of huff and puff production in ordinary heavy oil reservoirs with thin layer edge and bottom water for 10 years. For viscous oil+nitrogen, the cumulative oil production in 10 cycles of huff and puff is 93.5% of that of steam huff and puff, but the accumulated water volume is only 23.1% of that of steam huff and puff, and no water steam needs to be injected when low-viscosity oil + nitrogen huff and puff (in the case of steam huff and puff, it needs to be injected every cycle). 3000m 3 -7500m 3 steam), and the cost of nitrogen injection is significantly lower than that of steam injection. Therefore, in this example, 3000m 3 of 150℃, 100mPa s (50℃) low-viscosity oil + nitrogen huff and puff is injected per cycle. The effect is comparable to that of steam huff and puff and the cost is significantly lower than that of steam huff and puff.
提高周期注入低粘油量至4000m 3，并将注入低粘油粘度降至37.5mPa·s(50℃)时，低粘油+氮气吞吐10周期累采油增至40866m 3，为蒸汽吞吐的1.08倍。进一步将注入低粘油的温度 升至200℃时，低粘油+氮气吞吐10周期累采油增至42952m 3，为蒸汽吞吐的1.13倍。可见，通过适当提高周期注入低粘油量、提高低粘油温度及降低低粘油粘度，可进一步提高薄层边底水普通稠油油藏低粘油+氮气吞吐的开采效果，累采油量可高于蒸汽吞吐，而累采水量远低于蒸汽吞吐。 When the injection period of low-viscosity oil is increased to 4000m 3 , and the viscosity of injected low-viscosity oil is reduced to 37.5mPa·s (50℃), the cumulative oil recovery of low-viscosity oil + nitrogen huff and puff for 10 cycles increases to 40,866m 3 , which is 1.08 of steam huff and puff times. When the injection temperature of low-viscosity oil was further increased to 200°C, the cumulative oil recovery of low-viscosity oil + nitrogen huff and puff for 10 cycles increased to 42952 m 3 , which was 1.13 times that of steam huff and puff. It can be seen that by appropriately increasing the amount of low-viscosity oil injected periodically, increasing the temperature of low-viscosity oil, and reducing the viscosity of low-viscosity oil, the recovery effect of low-viscosity oil + nitrogen huff and puff in ordinary heavy oil reservoirs with thin edge and bottom water can be further improved, and the cumulative oil recovery It can be higher than steam huff and puff, and the cumulative water production is much lower than that of steam huff and puff.
表10薄层边底水普通稠油油藏不同方式开采10年数值模拟计算的单井注采参数Table 10 Single-well injection-production parameters calculated by numerical simulation of 10-year production of ordinary heavy oil reservoirs with thin edge and bottom water
Figure PCTCN2021075005-appb-000014
Figure PCTCN2021075005-appb-000014
本实施例中，针对部署水平井的薄层边底水普通稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时，注入低粘油的粘度可为5mPa·s-300mPa·s(50℃)，注入温度可为100℃-300℃，低粘油注入强度可为5m 3/m油层-15m 3/m油层，具体可参考本发明提供的方法通过计算来确定，注入气体可为天然气、氮气、二氧化碳、烟道气等气体，气体注入量与低粘油注入量在大气压下的体积比为50-100，注入方式可为混合注入或者后续段塞注入。注采周期可为8-16个月。注入低粘油和气体后的焖井时间可为1-10天。 In this embodiment, for the thin-layer edge-bottom water common heavy oil reservoir in which horizontal wells are deployed, the viscosity of the injected low-viscosity oil can be 5 mPa·s- 300mPa·s (50℃), the injection temperature can be 100℃-300℃, and the injection strength of low-viscosity oil can be 5m 3 /m oil layer-15m 3 /m oil layer, which can be determined by calculation with reference to the method provided in the present invention, The injected gas can be natural gas, nitrogen, carbon dioxide, flue gas, etc. The volume ratio of gas injection to low-viscosity oil injection under atmospheric pressure is 50-100. The injection method can be mixed injection or subsequent slug injection. The injection period can be 8-16 months. The soaking time after injection of low viscosity oil and gas can be 1-10 days.
实施例5.1Example 5.1
在本实施例中，采用现场就地蒸馏低粘油馏分吞吐开采部署直井的低含油饱和度普通稠油油藏。In this embodiment, the low-viscosity oil fraction huff-puff production and deployment of vertical wells are used in on-site in-situ distillation of low-viscosity oil fraction common heavy oil reservoirs.
本实施例中注入的低粘油为油田采出低粘油，50℃粘度为70mPa·s，经过加热炉加热后通过直井注入低含油饱和度普通稠油油藏，同时，通过油井隔热油管和套管环空注入氮气，进行低粘油和氮气吞吐。The low-viscosity oil injected in this example is low-viscosity oil produced in the oil field, and has a viscosity of 70 mPa·s at 50°C. After being heated in a heating furnace, it is injected into an ordinary heavy oil reservoir with low oil saturation through a vertical well. Nitrogen is injected into the casing annulus for low-viscosity oil and nitrogen huff and puff.
油藏模型的结构与实施例3.2相同，如图7所示。不同之处是油藏深度为1500m，地层条件下稠油粘度为1065mPa·s，脱气油粘度为8700mPa·s，地层渗透率为2000mD，原始油层温度为60℃，原始油层压力为15MPa，原始含油饱和度0.55，含水饱和度为0.45。油藏按正方形井网部署4口直井，井距100m，油层均射孔。数值模拟油藏模型共有40×40×10个网格，网格X方向和Y方向大小均为5m，网格Z方向大小为1m。The structure of the reservoir model is the same as in Example 3.2, as shown in Figure 7. The difference is that the reservoir depth is 1500m, the viscosity of heavy oil is 1065mPa·s under formation conditions, the viscosity of degassed oil is 8700mPa·s, the formation permeability is 2000mD, the original oil layer temperature is 60℃, the original oil layer pressure is 15MPa, and the original oil layer pressure is 15MPa. The oil saturation is 0.55 and the water saturation is 0.45. Four vertical wells are deployed in the reservoir according to the square well pattern, the well spacing is 100m, and the oil layers are perforated. The numerical simulation reservoir model has a total of 40×40×10 grids, the size of the grid in the X and Y directions is 5m, and the size of the grid in the Z direction is 1m.
本实施例中注入低粘油和氮气吞吐进行开采部署直井的低含油饱和度普通稠油油藏，注入低粘油和氮气吞吐开采时，吞吐10周期，每周期注采周期为1年，共开采10年。注入的低粘油50℃粘度为70mPa·s，注入温度为150℃。根据本发明提供的直井低粘油注入强度设计方法，可得低粘油吞吐的合理注入强度为76.3m 3/m-88.4m 3/m，注入氮气与低粘油的体积比为92，据此设计周期低粘油的注入量为1200m 3，注入氮气与注入低粘油的体积比为100(考虑到现场普通注氮气设备日注入量为20000m 3，蒸馏装置满足的低粘油日注入量为300m 3，在注低粘油阶段注入氮气与低粘油的体积比为66.7，但在停注低粘油后连续注入氮气，最后注入氮气与低粘油 的体积比为100)。单井日注油量为300m 3/d，焖井时间均为3天，采油时单井最高日产液量50m 3/d，最低流压为0.5MPa。为了对比效果，还进行了10周期蒸汽吞吐开采模拟，每周期注采周期为1年，共开采10年。单井第1周期注汽速度为200m 3/d，后续周期注汽速度均为300m 3/d。单井前4周期的周期注汽量分别为1000m 3、1500m 3、1800m 3、2400m 3，后6周期均为3000m 3。各周期注汽温度均为344℃、注汽干度均为0.2，焖井时间均为3天，采油时单井最高日产液量50m 3/d，最低流压为0.5MPa。另外，还开展了蒸汽吞吐5周期后转注入低粘油和氮气吞吐模拟，前5周期蒸汽吞吐注采参数前面蒸汽吞吐相同，后5周期注入的低粘油50℃粘度为70mPa·s，注入温度为150℃，单井日注油量为300m 3/d，单井周期注低粘油的量为1200m 3，焖井时间均为3天，采油时单井最高日产液量50m 3/d，最低流压为0.5MPa。 In this example, low-viscosity oil and nitrogen huff and puff are injected for production and low-saturation ordinary heavy oil reservoirs with vertical wells are deployed. When low-viscosity oil and nitrogen huff and puff are injected for production, the huff and puff cycle is 10 cycles, and the injection and production cycle of each cycle is 1 year. Mining for 10 years. The injected low-viscosity oil had a viscosity of 70 mPa·s at 50°C, and an injection temperature of 150°C. According to the low-viscosity oil injection strength design method for vertical wells provided by the present invention, the reasonable injection strength of low-viscosity oil huff and puff can be obtained as 76.3m 3 /m-88.4m 3 /m, and the volume ratio of injected nitrogen to low-viscosity oil is 92. The injection volume of low-viscosity oil in this design period is 1200m 3 , and the volume ratio of injected nitrogen gas to injected low-viscosity oil is 100 (considering that the daily injection volume of ordinary nitrogen injection equipment on site is 20,000m 3 , the daily injection volume of low-viscosity oil in the distillation unit is satisfied is 300m 3 , the volume ratio of nitrogen to low-viscosity oil is 66.7 in the low-viscosity oil injection stage, but after the injection of low-viscosity oil is stopped, nitrogen is continuously injected, and finally the volume ratio of nitrogen to low-viscosity oil is 100). The daily oil injection rate of a single well is 300m 3 /d, and the soaking time is 3 days. During oil production, the maximum daily liquid production of a single well is 50m 3 /d, and the minimum flow pressure is 0.5MPa. In order to compare the effect, a 10-cycle steam huff and puff mining simulation was also carried out. The steam injection rate of the first cycle of a single well is 200m 3 /d, and the steam injection rate of the subsequent cycles is 300m 3 /d. The cyclical steam injection volumes of the first 4 cycles of a single well are 1000m 3 , 1500m 3 , 1800m 3 and 2400m 3 respectively, and the latter 6 cycles are all 3000m 3 . In each cycle, the steam injection temperature was 344℃, the dryness of steam injection was 0.2, and the soaking time was 3 days. During oil production, the maximum daily liquid production of a single well was 50m 3 /d, and the minimum flow pressure was 0.5MPa. In addition, the simulation of low-viscosity oil and nitrogen huff and puff after 5 cycles of steam huff and puff was also carried out. The injection and production parameters of steam huff and puff in the first 5 cycles were the same as those of steam huff and puff. The temperature is 150℃, the daily oil injection rate of a single well is 300m 3 /d, the periodical injection rate of low-viscosity oil in a single well is 1200m 3 , the soaking time is 3 days, and the maximum daily liquid production of a single well is 50m 3 /d during oil production. The minimum flow pressure is 0.5MPa.
采用CMG公司的STARS热采模拟器，针对上述部署直井的低含油饱和度普通稠油油藏，开展了注入低粘油和氮气吞吐及蒸汽吞吐数值模拟计算，整个油藏的注采参数见表11。可见，对于本实施例中的部署直井的低含油饱和度普通稠油油藏，注入150℃、粘度为70mPa·s(50℃)的低粘油和氮气进行吞吐时，当周期低粘油注入量为1200m 3、注氮气10-12万m 3时，吞吐10年单井累积采油量为19428.2m 3，为蒸汽吞吐的96.2％，二者接近。由于低含油饱和油藏可流动水饱和高，造成蒸汽吞吐和低粘油与氮气吞吐的周期采水量高，但低粘油与氮气吞吐的累积采水量仅为蒸汽吞吐的70％-80％。如果在蒸汽吞吐5周期后进行低粘油和氮气吞吐的累积采油量为蒸汽吞吐的1.08倍，表明蒸汽吞吐中后期转为注低粘油和氮气吞吐会取得更好的开采效果。 Using CMG's STARS thermal recovery simulator, numerical simulation calculations of low-viscosity oil injection, nitrogen huff and puff and steam huff and puff were carried out for the normal heavy oil reservoirs with low oil saturation and vertical wells. The injection and production parameters of the entire reservoir are shown in the table 11. It can be seen that for the ordinary heavy oil reservoir with low oil saturation and low oil saturation in this example, when low-viscosity oil with a viscosity of 150°C and a viscosity of 70mPa·s (50°C) and nitrogen are injected for huff and puff, when the periodic low-viscosity oil is injected When the oil volume is 1200m 3 and nitrogen injection is 100,000-120,000 m 3 , the cumulative oil recovery of a single well in 10 years of huff and puff is 19428.2m 3 , which is 96.2% of that of steam huff and puff, and the two are close to each other. Due to the high flowable water saturation in low oil-saturated reservoirs, the cyclical water recovery of steam huff and puff and low-viscosity oil and nitrogen huff and puff is high, but the cumulative water production of low-viscosity oil and nitrogen huff and puff is only 70%-80% of that of steam huff and puff. If the cumulative oil recovery of low-viscosity oil and nitrogen huff and puff after 5 cycles of steam huff and puff is 1.08 times that of steam huff and puff, it shows that switching to low-viscosity oil and nitrogen huff and puff in the middle and late stage of steam huff and puff will achieve better recovery effect.
本实施例中，针对部署直井的低含油饱和度普通稠油油藏，采用本发明的利用现场就地蒸馏低粘油馏分吞吐开采时，最佳时机为蒸汽吞吐开采2-3周期后或者冷采3年后，注入低粘油的粘度可为5mPa·s-300mPa·s(50℃)，注入温度可为100℃-300℃，低粘油注入强度可为50m 3/m油层-100m 3/m油层，具体可参考本发明提供的方法通过计算来确定，注入气体可为天然气、氮气、二氧化碳、烟道气等气体，气体注入量与低粘油注入量在大气压下的体积比为30-120，注入方式可为混合注入或者后续段塞注入。注采周期可为6-12个月。注入低粘油和气体后的焖井时间可为1-10天。 In this embodiment, for low oil saturation common heavy oil reservoirs with vertical wells deployed, when the low-viscosity oil fraction huff and puff is exploited by on-site distillation of the present invention, the best time is after 2-3 cycles of steam huff and puff or cold After 3 years of production, the viscosity of injected low-viscosity oil can be 5mPa·s-300mPa·s (50℃), the injection temperature can be 100℃-300℃, and the injection strength of low-viscosity oil can be 50m 3 /m oil layer-100m 3 /m oil layer, which can be determined by calculation with reference to the method provided by the present invention. The injected gas can be natural gas, nitrogen, carbon dioxide, flue gas and other gases, and the volume ratio of the gas injection amount to the low-viscosity oil injection amount under atmospheric pressure is 30 -120, the injection mode may be mixed injection or subsequent slug injection. The injection period can be 6-12 months. The soaking time after injection of low viscosity oil and gas can be 1-10 days.
表11部署直井的低含油饱和度普通稠油油藏低粘油和氮气吞吐数值模拟计算的单井注采参数Table 11. Single-well injection-production parameters calculated by numerical simulation of low-viscosity oil and nitrogen huff and puff in normal heavy oil reservoirs with low oil saturation and vertical wells
Figure PCTCN2021075005-appb-000015
Figure PCTCN2021075005-appb-000015
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (28)

  1. 一种高粘油的开采方法，其中，该方法是将高温低粘油或者高温低粘油与气体的组合注入高粘油油藏进行吞吐开采的方法；A method for producing high-viscosity oil, wherein the method is a method for injecting high-temperature and low-viscosity oil or a combination of high-temperature and low-viscosity oil and gas into a high-viscosity oil reservoir for huff and puff production;
    其中，所述高温低粘油或者高温低粘油与气体的组合将地层中的高粘油通过溶解和加热进行降粘，并增加地层压力；所述高温低粘油包括高粘油蒸馏所得轻质馏分和中间馏分中的一种或两种以上的组合；所述轻质馏分是将经过脱水脱盐处理的高粘油进行常压蒸馏得到的；所述中间馏分是将经过脱水脱盐处理的高粘油进行常压蒸馏得到的重质馏分进行减压蒸馏得到的。Wherein, the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas reduces the viscosity of the high-viscosity oil in the formation by dissolving and heating, and increases the formation pressure; One or a combination of one or more of the light fraction and the middle fraction; the light fraction is obtained by carrying out atmospheric distillation of the high-viscosity oil that has undergone dehydration and desalination; The heavy fraction obtained by atmospheric distillation of viscous oil is obtained by vacuum distillation.
  2. 根据权利要求1所述的开采方法，其中，以所述经过脱水脱盐处理的高粘油与低粘油的混合物进行常压蒸馏。The production method according to claim 1, wherein atmospheric distillation is performed with the mixture of the dewatered and desalinated high-viscosity oil and the low-viscosity oil.
  3. 根据权利要求1或2所述的开采方法，其中，所述低粘油包括油田低粘油油藏开采的低粘油或粘度低于高粘油的油。The production method according to claim 1 or 2, wherein the low-viscosity oil comprises low-viscosity oil or oil whose viscosity is lower than that of high-viscosity oil produced from a low-viscosity oil reservoir in an oil field.
  4. 根据权利要求1-3任一项所述的开采方法，其中，所述气体包括天然气、氮气、二氧化碳和烟道气中的一种或两种以上的组合。The production method according to any one of claims 1-3, wherein the gas comprises one or a combination of two or more of natural gas, nitrogen, carbon dioxide and flue gas.
  5. 根据权利要求1-4任一项所述的开采方法，其中，所述将高温低粘油与气体的组合注入高粘油油藏的地层按照将二者进行同时注入或段塞式注入的方式，其中，所述同时注入是采用使高温低粘油和气体在地面管线混合、井口混合或井底混合的方式进行。The production method according to any one of claims 1-4, wherein the combination of high-temperature and low-viscosity oil and gas is injected into the formation of the high-viscosity oil reservoir according to the method of simultaneous injection or slug injection of the two , wherein the simultaneous injection is performed by mixing high temperature and low viscosity oil and gas in the surface pipeline, wellhead mixing or bottom hole mixing.
  6. 根据权利要求1-5任一项所述的开采方法，其中，注入高粘油油藏地层的高温低粘油或高温低粘油与气体的组合的温度控制在安全注入温度以下；该低粘油安全注入温度根据所述高温低粘油或高温低粘油与气体的组合的最低着火温度来确定。The production method according to any one of claims 1-5, wherein the temperature of the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas injected into the high-viscosity oil reservoir formation is controlled below a safe injection temperature; The oil safe injection temperature is determined according to the minimum ignition temperature of the high temperature and low viscosity oil or the combination of the high temperature and low viscosity oil and gas.
  7. 根据权利要求1-6任一项所述的开采方法，其中，所述高温低粘油的最高注入温度为100℃-240℃；所述高温低粘油与气体的组合的最高注入温度为240℃-300℃。The production method according to any one of claims 1-6, wherein the maximum injection temperature of the high temperature and low viscosity oil is 100°C-240°C; the maximum injection temperature of the combination of the high temperature and low viscosity oil and gas is 240°C ℃-300℃.
  8. 根据权利要求6或7所述的开采方法，其中，所述最低着火温度根据所述高温低粘油或高温低粘油与气体的组合的成分组成的着火温度来估算，并通过着火模拟实验来确定。The production method according to claim 6 or 7, wherein the minimum ignition temperature is estimated according to the ignition temperature of the composition of the high-temperature and low-viscosity oil or the combination of the high-temperature and low-viscosity oil and gas, and is determined by an ignition simulation experiment. Sure.
  9. 根据权利要求8所述的开采方法，其中，所述着火模拟实验采用着火模拟实验装置进行，该着火模拟实验装置至少包括：第一注入泵、第一中间容器、高温箱、加热盘管、回压阀、可视燃烧釜、收集器、空气气瓶、氧气气瓶、氮气气瓶、压力表；其中，所述第一注入泵通过管线与第一中间容器的底部相连，第一中间容器的上部出口通过管线与高温箱中的加热盘管的入口相连，所述加热盘管的出口通过管线与回压阀相连，所述回压阀通过管线与所述可视燃烧釜相连，所述可视燃烧釜的上部通过管线与所述空气气瓶、氧气气瓶和氮气气瓶分别相连，管线上安装有压力表，所述可视燃烧釜的下部通过管线与所述收集器相连。The mining method according to claim 8, wherein the ignition simulation experiment is performed using an ignition simulation experiment device, and the ignition simulation experiment device at least comprises: a first injection pump, a first intermediate container, a high temperature box, a heating coil, a return Pressure valve, visual combustion kettle, collector, air cylinder, oxygen cylinder, nitrogen cylinder, pressure gauge; wherein, the first injection pump is connected to the bottom of the first intermediate container through a pipeline, and the first intermediate container is connected to the bottom of the first intermediate container. The upper outlet is connected to the inlet of the heating coil in the high temperature box through a pipeline, the outlet of the heating coil is connected to a back pressure valve through a pipeline, and the back pressure valve is connected to the visible combustion kettle through a pipeline, and the The upper part of the visual combustion kettle is connected to the air cylinder, the oxygen cylinder and the nitrogen cylinder respectively through pipelines, a pressure gauge is installed on the pipelines, and the lower part of the visual combustion kettle is connected to the collector through pipelines.
  10. 根据权利要求9所述的开采方法，其中，所述着火模拟实验装置还包括第二注入泵和第二中间容器，所述第二注入泵通过管线与第二中间容器的底部相连，第二中间容器的上部出口通过管线与高温箱中的加热盘管的入口相连。The mining method according to claim 9, wherein the fire simulation experiment device further comprises a second injection pump and a second intermediate vessel, the second injection pump is connected to the bottom of the second intermediate vessel through a pipeline, and the second intermediate vessel is connected to the bottom of the second intermediate vessel through a pipeline. The upper outlet of the vessel is connected by a line to the inlet of the heating coil in the high temperature box.
  11. 根据权利要求9或10所述的开采方法，其中，所述注入泵的最高注入压力为30MPa-70MPa，所述高温箱的最高加热温度在500℃以上、控温精度≤±0.5℃，所述回压阀的控压范围为0-70MPa，加热盘管的长度为10m-20m、直径为3mm、耐压30MPa-70MPa，所述可视燃烧釜的实验压力范围为0-10MPa、并配备耐压视窗和加热控温系统；所述加热盘管与所述可视燃烧釜之间的管线设有保温部件。The mining method according to claim 9 or 10, wherein the maximum injection pressure of the injection pump is 30MPa-70MPa, the maximum heating temperature of the high temperature box is above 500°C, and the temperature control accuracy is ≤±0.5°C, the said The pressure control range of the back pressure valve is 0-70MPa, the length of the heating coil is 10m-20m, the diameter is 3mm, and the pressure resistance is 30MPa-70MPa. The experimental pressure range of the visual combustion kettle is 0-10MPa. A pressure viewing window and a heating and temperature control system; the pipeline between the heating coil and the visible combustion kettle is provided with a thermal insulation component.
  12. 根据权利要求11所述的开采方法，其中，所述保温部件包括绝缘材料。12. The mining method of claim 11, wherein the insulating member comprises an insulating material.
  13. 根据权利要求8-12任一项所述的开采方法，其中，所述着火模拟实验包括以下步骤；The mining method according to any one of claims 8-12, wherein the ignition simulation experiment comprises the following steps;
    根据高温低粘油的组成选择相应的馏分和/或低粘油制成实验样品，或者将高温低粘油直接作为实验样品；将实验样品加入第一中间容器，通过第一注入泵加压使实验样品注入高温箱中的加热盘管，高温箱设定温度为实验温度，通过回压阀将加热至实验温度的实验样品控制在实验压力水平，使高温高压的实验样品进入设定温度、压力和气体环境下的可视燃烧釜，通过视窗观察流进可视燃烧釜的实验样品是否着火；According to the composition of the high temperature and low viscosity oil, select the corresponding fraction and/or low viscosity oil to make the experimental sample, or use the high temperature and low viscosity oil directly as the experimental sample; add the experimental sample to the first intermediate container, and pressurize the first injection pump to make the experimental sample. The experimental sample is injected into the heating coil in the high temperature box. The set temperature of the high temperature box is the experimental temperature. The experimental sample heated to the experimental temperature is controlled at the experimental pressure level through the back pressure valve, so that the experimental sample of high temperature and high pressure enters the set temperature and pressure. And the visual combustion kettle in the gas environment, observe whether the experimental sample flowing into the visual combustion kettle is on fire through the window;
    其中，所述回压阀控制的实验压力根据现场高温低粘油或高温低粘油与气体的组合的注入压力来设定，所述可视燃烧釜的温度、压力和气体环境模拟可能发生泄漏的环境；Wherein, the experimental pressure controlled by the back pressure valve is set according to the injection pressure of the high-temperature and low-viscosity oil or the combination of high-temperature and low-viscosity oil and gas on site, and the temperature, pressure and gas environment of the visual combustion kettle can simulate that leakage may occur environment of;
    所述高温箱的加热温度根据注入实验样品可能着火的温度来确定，实验时根据实验样品的组成预估最低着火温度，并上调和下调一定温度进行着火模拟实验，并根据着火模拟实验结果放大或缩小调整着火模拟实验的加热温度，直至测定实验样品的最低着火温度；将最低着火温度乘以安全系数可得相应的高温低粘油的安全注入温度。The heating temperature of the high temperature box is determined according to the possible ignition temperature of the injected experimental sample. During the experiment, the minimum ignition temperature is estimated according to the composition of the experimental sample, and the ignition simulation experiment is carried out by raising and lowering a certain temperature, and according to the ignition simulation experiment results. Reduce and adjust the heating temperature of the ignition simulation experiment until the minimum ignition temperature of the experimental sample is determined; multiply the minimum ignition temperature by the safety factor to obtain the corresponding safe injection temperature of high temperature and low viscosity oil.
  14. 根据权利要求13所述的开采方法，其中，在将实验样品加入第一中间容器，通过第一注入泵加压使实验样品注入高温箱中的加热盘管的步骤中，当需要注入气体时，该步骤的操作还包括：气体加入第二中间容器，通过第二注入泵加压使气体与实验样品混合后进入高温箱中的加热盘管。The mining method according to claim 13, wherein, in the step of adding the experimental sample into the first intermediate container, and injecting the experimental sample into the heating coil in the high temperature box by the first injection pump, when gas needs to be injected, The operation of this step further includes: adding the gas into the second intermediate container, pressurizing the gas and the experimental sample through the second injection pump, and then entering the heating coil in the high temperature box.
  15. 根据权利要求13或14所述的开采方法，其中，进行所述着火模拟实验的温度为根据所述预估最低着火温度上调和下调5℃-10℃。The mining method according to claim 13 or 14, wherein the temperature at which the ignition simulation experiment is performed is increased and decreased by 5°C to 10°C according to the estimated minimum ignition temperature.
  16. 根据权利要求13-15任一项所述的开采方法，其中，所述着火温度预估可根据实验样品的组成以及各组成成分的着火温度进行体积加权平均或者质量加权平均来估算。The mining method according to any one of claims 13-15, wherein the estimated ignition temperature can be estimated by performing a volume-weighted average or a mass-weighted average on the composition of the experimental sample and the ignition temperature of each composition.
  17. 根据权利要求1-16任一项所述的开采方法，其中，在注入高粘油油藏的地层之前，所述高温低粘油先与进行沉降处理和/或脱水脱盐处理的高粘油进行换热，以使其降温至安全注入温度。The production method according to any one of claims 1-16, wherein, before injecting into the formation of a high-viscosity oil reservoir, the high-temperature and low-viscosity oil is first subjected to sedimentation treatment and/or dehydration and desalination treatment of high-viscosity oil. Heat exchange to cool it down to a safe injection temperature.
  18. 根据权利要求1-17任一项所述的开采方法，其中，该开采方法包括以下步骤：The mining method according to any one of claims 1-17, wherein the mining method comprises the steps of:
    通过油管和油套环空向高粘油生产井注入顶替介质顶替油管和油套环空中的空气；The displacement medium is injected into the high-viscosity oil production well through the oil pipe and the oil casing annulus to displace the air in the oil pipe and the oil casing annulus;
    将高温低粘油通过生产井的油管注入高粘油油藏地层中，所述高温低粘油的注入量根据高粘油粘度、油藏开采程度和油井类型来确定；injecting the high-temperature and low-viscosity oil into the high-viscosity oil reservoir formation through the tubing of the production well, and the injection amount of the high-temperature and low-viscosity oil is determined according to the viscosity of the high-viscosity oil, the degree of oil recovery and the type of the oil well;
    在注入高温低粘油的过程中或者注入高温低粘油之后，通过油管和/或油套环空注入气体，以扩大注入的高温低粘油的地层波及范围；In the process of injecting high temperature and low viscosity oil or after injecting high temperature and low viscosity oil, gas is injected through the oil pipe and/or the oil casing annulus, so as to expand the stratum swept range of the injected high temperature and low viscosity oil;
    注入结束并焖井一段时间后，油井开井生产。After the injection is completed and the well is soaked for a period of time, the oil well is opened for production.
  19. 根据权利要求18所述的开采方法，其中，所述顶替介质包括低温低粘油、气体和水中的一种或两种以上的组合。The production method according to claim 18, wherein the displacement medium comprises one or a combination of two or more of low temperature and low viscosity oil, gas and water.
  20. 根据权利要求18所述的开采方法，其中，所述注入气体与低粘油在大气压下的体积比根据低粘油注入量、气体在低粘油中的溶解度、气体波及范围、波及范围内地层流体饱和度、以及所要达到的油层压力来确定。The production method according to claim 18, wherein the volume ratio of the injected gas to the low-viscosity oil under atmospheric pressure is based on the injection amount of the low-viscosity oil, the solubility of the gas in the low-viscosity oil, the gas swept range, and the formation in the swept range. The fluid saturation and the reservoir pressure to be reached are determined.
  21. 根据权利要求18所述的开采方法，当油井开采一段时间且油井产量降至一定水平后，结束本周期开采，转下一周期注高温低粘油或高温低粘油与气体的组合进行吞吐。According to the production method of claim 18, when the oil well is produced for a period of time and the production of the oil well drops to a certain level, the current production cycle is terminated, and the next cycle is followed by injection of high temperature and low viscosity oil or a combination of high temperature and low viscosity oil and gas for huff and puff.
  22. 根据权利要求18所述的开采方法，其中，所述高温低粘油注入量、高温低粘油与气体的组合的低粘油注入量根据高粘油粘度、油藏开采程度和油井类型来确定。The production method according to claim 18, wherein the injection amount of the high-temperature and low-viscosity oil and the low-viscosity oil injection amount of the combination of the high-temperature and low-viscosity oil and gas are determined according to the viscosity of the high-viscosity oil, the degree of oil recovery and the type of oil well .
  23. 根据权利要求22所述的开采方法，其中，所述油藏开采程度根据油藏可波及半径来表征，所述油藏可波及半径为已动用油藏外边界到生产井的距离；当为新投产直井或定向井第一周期时，油藏可波及半径可以为3m-5m；当为新投产水平井、分支井和鱼骨井第一周期时，油藏可波及半径可以为1m-3m。The production method according to claim 22, wherein the oil reservoir production degree is characterized according to the swept radius of the oil reservoir, and the swept radius of the oil reservoir is the distance from the outer boundary of the produced oil reservoir to the production well; When the first cycle of vertical wells or directional wells is put into production, the swept radius of the reservoir can be 3m-5m; when it is the first cycle of new horizontal wells, lateral wells and fishbone wells, the swept radius of the reservoir can be 1m-3m.
  24. 根据权利要求22所述的开采方法，其中，所述吞吐开采高粘油时的高温低粘油的注入强度为每米油层周期注入高温低粘油的量，可根据下式计算：The production method according to claim 22, wherein the injection intensity of the high-temperature and low-viscosity oil during the huff and puff production of high-viscosity oil is the amount of high-temperature and low-viscosity oil injected per meter of oil layer period, which can be calculated according to the following formula:
    I o＝[a+b ln(R/h)]·[c ln ln(μ)-d] I o =[a+b ln(R/h)]·[c ln ln(μ)-d]
    式中，I o为低粘油注入强度，m 3/m；a和b为与油藏动用程度有关的参数，c和d为与高粘油粘度有关的参数，可根据目标油藏条件通过油藏数值模拟或现场应用结果来确定；R为油藏可波及半径，m；h为油藏厚度，m；μ为地层条件下高粘油的粘度，mPa·s。 In the formula, I o is the injection strength of low-viscosity oil, m 3 /m; a and b are parameters related to the degree of reservoir production, c and d are parameters related to the viscosity of high-viscosity oil, which can be passed according to the target reservoir conditions. Reservoir numerical simulation or field application results to determine; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; μ is the viscosity of high-viscosity oil under formation conditions, mPa·s.
  25. 根据权利要求22-24任一项所述的开采方法，其中，当生产井为直井或定向井时，所述低粘油的注入强度为：The production method according to any one of claims 22-24, wherein, when the production well is a vertical well or a directional well, the injection strength of the low-viscosity oil is:
    I ho＝[1+0.15ln(R/h)]·[120ln ln(μ)-150] I ho =[1+0.15ln(R/h)]·[120lnln(μ)-150]
    式中，I ho为低粘油注入强度，m 3/m；R为油藏可波及半径，m；h为油藏厚度，m；μ为地层条件下高粘油的粘度，mPa·s。 where I ho is the injection strength of low-viscosity oil, m 3 /m; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; μ is the viscosity of high-viscosity oil under formation conditions, mPa·s.
  26. 根据权利要求25所述的开采方法，其中，当生产井为水平井、分支井或鱼骨井时，所述低粘油的注入强度为：The production method according to claim 25, wherein, when the production well is a horizontal well, a lateral well or a fishbone well, the injection strength of the low-viscosity oil is:
    I ho＝[1+0.1ln(R/h)]·[12ln ln(μ)-15] I ho =[1+0.1ln(R/h)]·[12lnln(μ)-15]
    式中，I ho为低粘油注入强度，m 3/m；R为油藏可波及半径，m；h为油藏厚度，m；μ为地层条件下高粘油的粘度，mPa·s。 where I ho is the injection strength of low-viscosity oil, m 3 /m; R is the swept radius of the reservoir, m; h is the thickness of the reservoir, m; μ is the viscosity of high-viscosity oil under formation conditions, mPa·s.
  27. 根据权利要求18-26任一项所述的开采方法，其中，在所述高温低粘油与气体的组合中，气体与所述高温低粘油在大气压下的体积比根据低粘油注入量、气体在低粘油中的溶解度、气体波及范围、波及范围内地层流体饱和度、以及所要达到的油层压力来确定；其中，所述气体波及范围根据油藏可波及半径、油层厚度和油层孔隙度来计算，所述油藏可波及半径为已动用油藏外边界到油井的距离。The production method according to any one of claims 18-26, wherein, in the combination of the high temperature and low viscosity oil and the gas, the volume ratio of the gas to the high temperature and low viscosity oil under atmospheric pressure is based on the injection amount of the low viscosity oil , the solubility of gas in low-viscosity oil, the gas sweep range, the formation fluid saturation in the sweep range, and the oil layer pressure to be reached; wherein, the gas sweep range is determined according to the swept radius of the reservoir, the thickness of the oil layer and the pores of the oil layer Calculated in degrees, the swept radius of the reservoir is the distance from the outer boundary of the produced reservoir to the oil well.
  28. 根据权利要求27所述的开采方法，其中，所述注入气体与低粘油在大气压下的体积比根据下式计算：The production method according to claim 27, wherein the volume ratio of the injected gas to the low-viscosity oil under atmospheric pressure is calculated according to the following formula:
    Figure PCTCN2021075005-appb-100001
    Figure PCTCN2021075005-appb-100001
    式中，IGOR为注入气体与低粘油在大气压下的体积比；I o为低粘油注入强度，m 3/m；D g为注入气体在注入油藏低粘油中的溶解度；R为油藏可波及半径，m；φ为油层平均孔隙度；S o为油藏波及范围内的油饱和度；S w为油藏波及范围内的水饱和度；S g为油藏波及范围内的气体饱和度；ΔP为油藏压力增加值，MPa；P 0为大气压力，MPa。 where IGOR is the volume ratio of injected gas to low-viscosity oil at atmospheric pressure; I o is the injection strength of low-viscosity oil, m 3 /m; D g is the solubility of injected gas in low-viscosity oil injected into the reservoir; R is Reservoir swept radius, m; φ is the average porosity of the reservoir; S o is the oil saturation within the swept range of the reservoir; Sw is the water saturation within the swept range of the reservoir; S g is the swept range of the reservoir Gas saturation; ΔP is the increase in reservoir pressure, MPa; P 0 is atmospheric pressure, MPa.
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