CN114135262B - Underground steam secondary electric heating pipe column and heating method - Google Patents
Underground steam secondary electric heating pipe column and heating method Download PDFInfo
- Publication number
- CN114135262B CN114135262B CN202111358907.1A CN202111358907A CN114135262B CN 114135262 B CN114135262 B CN 114135262B CN 202111358907 A CN202111358907 A CN 202111358907A CN 114135262 B CN114135262 B CN 114135262B
- Authority
- CN
- China
- Prior art keywords
- steam
- cable core
- pipe
- oil pipe
- connector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000010438 heat treatment Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000005485 electric heating Methods 0.000 title claims abstract description 15
- 238000010793 Steam injection (oil industry) Methods 0.000 claims abstract description 21
- 238000007789 sealing Methods 0.000 claims description 61
- 238000012856 packing Methods 0.000 claims description 32
- 238000004519 manufacturing process Methods 0.000 claims description 27
- 239000012212 insulator Substances 0.000 claims description 24
- 230000001681 protective effect Effects 0.000 claims description 21
- 230000008878 coupling Effects 0.000 claims description 20
- 238000010168 coupling process Methods 0.000 claims description 20
- 238000005859 coupling reaction Methods 0.000 claims description 20
- 238000009413 insulation Methods 0.000 claims description 13
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 10
- 238000000605 extraction Methods 0.000 claims description 10
- 239000000565 sealant Substances 0.000 claims description 8
- 238000012360 testing method Methods 0.000 claims description 6
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 239000000395 magnesium oxide Substances 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- 239000003822 epoxy resin Substances 0.000 claims description 4
- 229920000647 polyepoxide Polymers 0.000 claims description 4
- 238000005086 pumping Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 3
- 229910000851 Alloy steel Inorganic materials 0.000 claims description 2
- 229910018487 Ni—Cr Inorganic materials 0.000 claims description 2
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 238000010796 Steam-assisted gravity drainage Methods 0.000 abstract description 11
- 230000000694 effects Effects 0.000 abstract description 11
- 238000009792 diffusion process Methods 0.000 abstract description 3
- 239000003921 oil Substances 0.000 description 91
- 238000010795 Steam Flooding Methods 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 239000003129 oil well Substances 0.000 description 6
- 230000003628 erosive effect Effects 0.000 description 5
- 239000012530 fluid Substances 0.000 description 5
- 230000003068 static effect Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 238000003303 reheating Methods 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- 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
- E21B43/2401—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection by means of electricity
-
- 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
- E21B43/2406—Steam assisted gravity drainage [SAGD]
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/40—Heating elements having the shape of rods or tubes
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Pipe Accessories (AREA)
Abstract
The invention discloses an underground steam secondary electric heating pipe column and a heating method, which relate to the field of thick oil exploitation of oil and gas field steam injection, and the coiled tubing and an electric heater are arranged under a steam wellhead, the electric heater at the bottom end carries out secondary heating on low-dryness steam at the bottom of the well, so that the temperature and pressure of the steam at the bottom of the well are increased, the dryness is greatly improved, the high-temperature and high-pressure diffusion of the steam is facilitated, the steam wave effect is improved, the operation effects of steam throughput, steam driving and SAGD are further improved, and the dryness index can be improved by 20-30%.
Description
Technical Field
The invention relates to the field of thick oil exploitation by steam injection of oil and gas fields, in particular to an underground steam secondary electric heating pipe column and a heating method.
Background
Because the viscosity of the thick oil in the oil is very high, the seepage resistance is high, and the water rising speed is high, the thick oil is mostly used for thermal recovery, and the main method comprises the following steps: steam stimulation, steam flooding, SAGD, fire flooding. Among them, steam injection thick oil extraction is the most important oil extraction mode. The steam injection to extract thick oil can improve the steam absorption capacity of an oil layer, improve the sweep efficiency and increase the fluidity of crude oil. The modes of steam throughput, steam flooding, SAGD and the like all need to be higher in dryness of steam injected into the well, but the practical effect is not ideal, because the longer the depth is, the longer the pipe column is, the greater the heat loss along the way is, most of steam reaching an underground oil layer becomes hot water, and the bottom layer has poor heat absorption condition. The Liaohe oilfield on-site steam injection system is influenced by factors such as boiler thermal efficiency, ground pipelines, shaft heat insulation and the like, the heat loss is large, the comprehensive utilization rate of heat energy is less than 60%, the limit depth of steam flooding injection and production is only about 1000m, steam flooding, SAGD and other technologies are implemented aiming at extra deep heavy oil reservoirs (1000-1700 m), and the bottom hole dryness is difficult to reach the development index requirement. There are some prior documents that mention downhole steam generators, which do not use surface boilers to generate steam, but use devices directly downhole to generate steam to inject into an oil layer, which have been reported abroad, but few embodiments are available. The underground steam generator needs water, fuel, air, an atomization chamber, a combustion chamber, a mixing chamber, a gasification chamber and the like corresponding to the water, the fuel and the air to burn and heat at the bottom of the well, has large research and development difficulty, high cost and complex process, and faces the problems of high-pressure combustion corrosion and the like.
Disclosure of Invention
In order to solve the problem of improving the dryness of underground steam, the invention provides an underground steam secondary electric heating tubular column and a heating method, which can carry out secondary heating on steam injected into the bottom of a thick oil well through the arrangement of a continuous oil pipe and an electric heater, improve the dryness of the injected steam and the swept volume of the steam at the bottom of the well, generate better displacement effect, and have great applicability to steam flooding and deep wells with SAGD depth of 1000-2000 meters.
The invention adopts the technical proposal for solving the technical problems that: the underground steam secondary electric heating pipe column comprises a continuous oil pipe and an electric heater, wherein the continuous oil pipe is provided with a cable core a, and the electric heater is provided with a cable core b and a heating wire connected with the cable core b; the head end of the cable core a is connected with a three-phase power supply of the control cabinet, the tail end of the cable core a is connected with the cable core b, and current is transmitted to the heating wire for heating through the cable core a and the cable core b after the three-phase power supply is electrified.
Further, the continuous oil pipe comprises a continuous pipe body, a cable core a, an insulator a, an upper sealing head and a lower sealing head, wherein at least one cable core a penetrates into the continuous pipe body, and the insulator a is fully distributed between the cable core a and the continuous pipe body; the upper end enclosure and the lower end enclosure are respectively arranged at two ends of the continuous pipe body and are used for sealing the insulator a.
Further, the electric heater comprises a protective tube, a cable core b, a heating wire, an insulator b and sealant, wherein one end of the protective tube is closed, the other end of the protective tube is open, and the open end of the protective tube is connected with the tail end of the continuous tube body; at least one cable core b penetrates into the protective tube, one end of the cable core b is connected with the tail end of the cable core a, the other end of the cable core b is connected with a heating wire, and the heating wire is positioned at the closed end of the protective tube; an insulator b is distributed among the cable core b, the heating wire and the protective tube; the sealant is connected to the open end of the protective tube for sealing the insulator b.
Furthermore, a non-coupling oil pipe for protection is sleeved outside the continuous oil pipe; a continuous oil pipe sealer for steam sealing is arranged between the head end of the continuous oil pipe and the head end of the non-coupling oil pipe.
Further, the coiled tubing sealer comprises an upper connector, a middle connector, a lower connector, an upper sealing packing and a lower sealing packing, wherein the upper connector is in threaded connection with the middle connector, the middle connector is internally provided with the upper sealing packing, and one end face of the upper sealing packing is contacted with the end part of the upper connector; the middle connector is in threaded connection with the lower connector, a lower sealing packing is arranged in the lower connector, and one end face of the lower sealing packing is contacted with the end part of the middle connector; the outer wall of the lower connector is provided with threads, the coupling-free oil pipe is connected with the lower connector through the threads, and the continuous oil pipe penetrates into the upper connector, the middle connector, the upper sealing packing, the lower connector and the lower sealing packing and then enters the coupling-free oil pipe.
Further, the integral temperature resistance of the continuous oil pipe is 600 ℃, and the pressure resistance is 25MPa; the power of the electric heater is 400 kilowatts, the integral temperature resistance is 600 ℃, and the pressure resistance is 25MPa; the whole continuous oil pipe sealer has 320 deg.c and 25MPa pressure resistance.
The downhole steam secondary electric heating method, which uses the downhole steam secondary electric heating pipe column, comprises the following steps: firstly, using an eccentric wellhead to put a non-coupling oil pipe into an operating nine-inch sleeve, and then using a continuous pipe injection device to put a continuous oil pipe and an electric heater into the non-coupling oil pipe; and then the central wellhead operation is carried out, the heat insulation pipe is put into the central wellhead operation for steam injection operation, the control cabinet is used for controlling the electric heater to heat and controlling the power to regulate, and the bottom steam is secondarily heated.
Further, after the steam injection operation, a heat insulation pipe is provided, an oil pipe and a tubular pump are arranged at the tail end of the oil pipe from a central wellhead, an oil pumping unit is arranged at the central wellhead, and the oil pumping unit is communicated with the oil pipe to carry out oil extraction production.
Further, the method further comprises the following steps: and a central wellhead is put into a sampler to sample and test the dryness of the bottom of the well, and a control cabinet regulates the power of the electric heater in real time according to the dryness value.
Further, the tail end of the heat insulation pipe is provided with a horn mouth.
The beneficial effects of the invention include: 1. the continuous oil pipe and the electric heater are arranged in the steam wellhead, the electric heater at the bottom end heats the low-dryness steam at the bottom of the well, so that the temperature and pressure of the steam at the bottom of the well are increased, the dryness is greatly improved, the high-temperature and high-pressure diffusion of the steam is facilitated, the steam wave effect is improved, the operation effects of steam throughput, steam flooding and SAGD are further improved, and the dryness index can be improved by 20-30%;
2. The coiled tubing sealer is arranged, can be used for steam sealing between the coiled tubing and the non-coupling tubing, can realize dynamic and static sealing, and ensures that no steam leakage occurs at a wellhead; the coiled tubing and the electric heater are put into the non-coupling tubing, the non-coupling tubing can prevent the thermal high-temperature steam at the wellhead from eroding the coiled tubing, and can also prevent the damage to the coiled tubing caused by the collision of the operation pipe column at one side;
3. the heating method adopts an eccentric wellhead mode, so that the heating pipe column and the steam injection pipe column are separated and not concentric, and the concentric same pipe mode can not only erode the whole underground continuous oil pipe and the outer wall of the electric heater, but also throttle the inlet steam flow, and an annular flow passage is generated, so that the heat loss along the underground is aggravated. The heating pipe column is arranged on the eccentric well head, so that high-temperature steam erosion of the well head can be prevented, steam is injected downwards from the central well head and the production pipe column is arranged on the eccentric well head, the heating pipe column and the steam injection pipe column are separated, the central well head can be subjected to subsequent operation, the production pipe column can be replaced to be used for pump production, a sampler can be arranged downwards for dryness sampling, the temperature and dryness of underground steam are controlled, the power adjustment of an electric heater is guided, the temperature and dryness of underground steam are controlled, and the functions of heating and testing at the same time can be realized.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the downhole steam secondary electric heating pipe column of the invention;
FIG. 2 is a schematic illustration of the coiled tubing construction of the present invention;
FIG. 3 is a cross-sectional view of the coiled tubing structure of the present invention;
FIG. 4 is a schematic view of an electric heater according to the present invention;
FIG. 5 is a cross-sectional view of an electric heater structure according to the present invention;
FIG. 6 is a schematic illustration of a coiled tubing sealer of the present invention;
FIG. 7 is a schematic diagram of a heating assisted oil recovery structure for a side bottom water reservoir according to example 3 of the present invention.
The reference numerals in the drawings illustrate: 1-nine-inch sleeve, 2-1-oil pipe, 2-2-heat insulation pipe, 3-1-pipe pump, 3-2-bell mouth, 4-coupling-free oil pipe, 5-continuous oil pipe, 6-electric heater, 7-continuous oil pipe sealer, 8-control cabinet, 9-cable core a, 10-upper end enclosure, 11-insulator a, 12-continuous pipe body, 13-lower end enclosure, 14-oil layer, 15-cable core b, 16-sealant, 17-protective pipe, 18-insulator b, 19-heating wire, 20-side bottom water layer, 21-upper sealing packing, 22-upper connector, 23-intermediate connector, 24-lower sealing packing, 25-lower connector, 26-screw thread, 27-bottom horizontal well, 28-vertical well, 29-oil layer horizontal well, 30-cap layer.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the azimuth or positional relationship indicated by the terms "vertical", "horizontal", "inner", "outer", etc., are based on the azimuth or positional relationship shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or component referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," second, "and third" are used merely to distinguish components and should not be construed as indicating or implying relative importance.
In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
Example 1
The invention has the whole design idea that: in order to improve the dryness of underground steam, a mode of heating the steam once by using a surface boiler and reheating the steam reaching the bottom of the well is considered, and for a deep well with steam flooding and SAGD depth of 1000-2000 meters, the mode can effectively improve the dryness of underground steam. According to the steam wellhead continuous oil pipe, the continuous oil pipe 5 and the electric heater 6 are arranged at the steam wellhead, the electric heater 6 at the bottom end heats low-dryness steam at the bottom of the well for the second time, so that the temperature and pressure of the steam at the bottom of the well are increased, the dryness is greatly improved, the high-temperature and high-pressure diffusion of the steam is facilitated, the steam wave effect is improved, the heating efficiency of the steam throughput, steam flooding and SAGD is improved, and the dryness index can be improved by 20-30%.
And for the downhole steam reheating technology, the downhole steam reheating is mainly aimed at. The thermodynamic characteristics of steam, air and the like are different, the heat capacity of the steam is large, and the steam can carry more heat at the same temperature, which is also the reason for adopting steam huff and puff and steam flooding in the on-site oil extraction process. Therefore, the steam at the bottom of the well is heated to generate high temperature and high pressure, more heat is needed, and the power of the electric heater needs to be large enough to generate enough energy to complete secondary heating.
The temperature of the steam wellhead is above 300 ℃, the pressure is about 12MPa, and a continuous oil pipe cable connected with the electric heater also needs to bear high temperature and high pressure. The cable in the common continuous oil pipe is generally resistant to 150 ℃ in temperature, so that the high-temperature resistant cable needs to be developed to bear the high temperature of steam, and the erosion and oxidization effects of the steam are also considered. Therefore, a high-power high-temperature and high-pressure resistant electric heater is required to be designed to complete the secondary heating function of well bottom steam, and well mouth sealing is not leaked for steam heating, which is also an important technical problem.
Based on the above consideration, the present invention makes the following specific schemes:
the embodiment mainly describes a horizontal well operation mode.
Referring to fig. 1, the wellhead adopts an eccentric wellhead mode, and in the nine inch casing 1 of the operation, firstly, a two inch non-coupling oil pipe 4 is put into the horizontal section initial position of the horizontal well by using the eccentric wellhead operation. Then, a coiled tubing injection device is utilized to put a coiled tubing 5 and an electric heater 6 into the non-coupling oil pipe 4, the length of a heating section of the electric heater 6 is about two hundred meters, and the heating section is positioned at the front part of an oil layer section of a horizontal well or at the designed running depth. The electric heater 6 is connected to the tail end of the continuous oil pipe 5, the continuous oil pipe 5 penetrates out of the wellhead through a continuous oil pipe sealer 7 arranged at the eccentric wellhead and is connected to the control cabinet 8, and the heating power of the electric heater 6 is adjusted through the control cabinet 8. Then the operation is carried out: the steam huff and puff or steam flooding operation is carried out by the central wellhead and the thermal insulation pipe 2-2 (namely a steam injection pipe column). The electric heater 6 is adjusted and heated through the control cabinet 8, so that secondary heating of bottom hole steam is realized, and the dryness and the steam wave effect of the steam are improved. For the steam huff-puff well, after the steam huff-puff is finished, the operation proposes that the heat insulation pipe 2-2 is put into the oil pipe 2-1 (namely the production pipe column) and the pipe pump 3-1 to carry out oil extraction production operation, so that the steam huff-puff operation for multiple times can be realized; the steam flooding well can be heated at the bottom of the well for a long time, the steam injection dryness is improved, meanwhile, the change of the dryness of the bottom of the well can be known through the sampling test of the dryness of the bottom of the well by the central well mouth, the power of the electric heater 6 is regulated in real time, and the regulation is dynamic regulation.
The heating method adopts an eccentric wellhead mode, the heating pipe column and the steam injection pipe column are separated and are not concentric, and the heating pipe column can prevent high-temperature steam erosion of the wellhead when moving away from the eccentric wellhead, and the steam injection pipe column and the production pipe column are arranged below the central wellhead. The coupling-free oil pipe 4 can prevent the thermal high-temperature erosion of the continuous oil pipe 5 by wellhead high-temperature steam and can also prevent the collision damage of the operation pipe column to the continuous oil pipe 5.
For the vertical well with an eccentric wellhead, the non-coupling oil pipe 4 can be selected not to be put into, the continuous oil pipe 5 and the electric heater 6 can be directly put into, and the vertical well is more suitable for well conditions with steam flooding and SAGD steam long-term heating without putting into a production string. The separation mode of the heating pipe column and the steam injection pipe column can enable the central wellhead to carry out subsequent operation, can change production pipe column pump production, can also put into a sampler to sample dryness, controls underground steam temperature and dryness, guides the power adjustment of the electric heater 6, controls underground steam temperature and dryness, and can realize the functions of heating and testing. For a vertical well, the central wellhead can be further provided with a steam-sucking section tester for testing the steam sucking condition of an oil layer.
Example 2
Coiled tubing 5 for use in the method described in example 1:
Comprises a continuous pipe body 12, a cable core a9, an insulator a11, an upper sealing head 10 and a lower sealing head 13,
In this embodiment, the outer diameter of the continuous pipe body 12 is 25.4mm, the wall thickness is 2.4mm, 316L stainless steel is adopted, three cable cores a9 are penetrated in the middle of the continuous pipe body, oxygen-free copper is adopted as the material of the cable cores a9, the diameter is 6mm, an insulator a11 is fully distributed between the cable cores a9 and the continuous pipe body 12, and magnesia powder is adopted as the material of the insulator a11, so that the continuous pipe can resist high temperature and transfer heat. The upper seal head 10 and the lower seal head 13 are respectively arranged at two ends of the continuous pipe body 12 and are used for sealing the insulator a11, so that the insulator a11 is isolated from the outside air and interference and damp are prevented. The upper seal head 10 and the lower seal head 13 are 10 cm long and made of epoxy resin. The length of the cable core a9 is processed according to the field requirement, the length is about two kilometers, the whole temperature resistance is 600 ℃, and the pressure resistance is 25MPa.
An electric heater 6:
comprises a protective tube 17, a cable core b15, a heating wire 19, an insulator b18 and a sealant 16,
In this embodiment, the outer diameter of the protective tube 17 is 25.4mm, the wall thickness is 2.4mm, and 825 alloy steel materials are adopted. The heating wire 19 has three cores, the core diameter is 4mm, and the heating wire is made of nickel-chromium material, can resist high temperature of 800 ℃ and is used as the hot end of the electric heater 6, and is mainly responsible for high-temperature heating and has the length of 200 meters. The cable core b15 is also a three-core, and is made of oxygen-free copper, and is used as the cold end of the electric heater 6, the length of the cable core b is 40m, and the temperature resistance of the cold end part is 600 ℃. The cable core b15 and the heating wire 19 are welded together in a socket joint mode. The insulator b18 is arranged between the protective tube 17 and the heating wire 19 as well as between the protective tube and the cable core b15 to play a role in insulating and sealing, and is made of magnesia powder, sealed at high temperature and conducting heat. The sealant 16 is made of epoxy resin and is used for sealing the insulator b18, so that the magnesia powder is not affected by external interference. The power of the electric heater 6 reaches 400 kilowatts, the whole temperature resistance is 600 ℃, and the pressure resistance is 25MPa.
In the embodiment, the coiled tubing 5 and the electric heater 6 are connected into a whole by butt welding, and the diameters of the coiled tubing and the electric heater are equal to each other and are 25.4mm in outer diameter. The three cores are mutually in butt welding between the cable core b15 of the electric heater 6 and the tail end of the cable core a9 of the continuous oil pipe 5, the continuous pipe body 12 of the continuous oil pipe 5 and the protective pipe 17 of the electric heater 6 are mutually in butt welding, the head end of the cable core a9 of the continuous oil pipe 5 is connected with a three-phase power supply of the control cabinet 8 during construction, and the three-core cable adopts a star-shaped connection mode after being electrified and conveyed to the hot end of the electric heater 6 at the underground bottom end by the cable core a9 for heating. The control cabinet 8 has 600KW power, outputs a voltage of 2000V, 50HZ AC power supply, and can adjust the power to provide power support for the electric heater 6 at the bottom of the well.
To prevent steam leakage from an eccentric wellhead, this embodiment provides a coiled tubing sealer 7 for steam sealing between a Φ25.4mm coiled tubing 5 and a Φ48.3mm non-jointed tubing 4.
Coiled tubing sealer 7:
Comprises an upper connector 22, a middle connector 23, a lower connector 25, an upper sealing packing 21 and a lower sealing packing 24,
First, an upper sealing packing 21 and a lower sealing packing 24 are respectively placed in an intermediate connecting body 23 and a lower connecting body 25, wherein the upper sealing packing 21 and the lower sealing packing 24 are formed by a plurality of circular hollow graphite gaskets, the thickness of each gasket is 0.2 cm, and the inner diameter is 25.4 mm. The upper sealing packing 21 and the lower sealing packing 24 are formed by overlapping graphite gaskets according to the field sealing thickness. The upper connector 22 and the middle connector 23 are connected through threads, and the upper sealing packing 21 in the middle connector 23 is pressed or loosened by screwing in and screwing out of the threads during sealing so as to seal the wall surface of the continuous oil pipe 5. The intermediate connection body 23 and the lower connection body 25 also seal against the lower sealing packing 24 in this way.
In this embodiment, the bottom end of the lower connector 25 is threaded with TBG, and is connected to the non-coupling tubing 4. During site construction, the coiled tubing 5 sequentially penetrates into the upper connector 22, the middle connector 23, the upper sealing packing 21, the lower connector 25 and the lower sealing packing 24, and then enters into the non-coupling tubing 4 connected with the bottom end of the lower connector 25 and then enters into the bottom hole.
The upper connector 22, the middle connector 23 and the upper sealing packing 21 form an upper-stage seal, and are mainly used for dynamic sealing, and play a role in sealing and not leaking steam in the bottom-hole lowering and wellhead lifting processes of the continuous oil pipe 5. The intermediate connector 23, the lower connector 25 and the lower sealing packing 24 form lower-stage sealing, which is mainly used for static sealing, and static sealing compaction is carried out when the continuous oil pipe 5 goes down to the bottom of the well and upper-stage sealing is loosened. When one stage is damaged and leaked, the other stage can also continue to function, and dynamic sealing and static sealing can be completed, so that double protection is facilitated. The integral seal can resist 320 ℃ high temperature and 25MPa.
In this embodiment, the horizontal well string adopts a nine inch casing 1 and an eccentric wellhead, and the bottom horizontal well completion mode can adopt a screen well completion or an open hole well completion. The tubing 4 with diameter of 48.3mm and no coupling is firstly put into the horizontal section from the eccentric wellhead operation. And then the coiled tubing operation machine is used for descending the coiled tubing 5 with the diameter of 25.4mm from the non-coupling tubing 4 with the diameter of 48.3mm until the coiled tubing 5 is always descended to the front end of the oil layer section of the horizontal section. The phi 48.3mm non-coupling oil pipe 4 is used as a protection pipe of the phi 25.4mm continuous oil pipe 5, and the phi 25.4mm continuous oil pipe 5 is protected from being put into the initial position of the horizontal section during operation, and the electric heater 6 is put into the front end of the horizontal well oil layer section under the action of injection force and gravity.
For steam flooding and SAGD wells, the central wellhead is operated to put into the phi 114mm heat insulation pipe 2-2 and the bell mouth 3-2 for long-term steam injection operation, the electric heater 6 realizes secondary heating at the bottom of the well, the dryness of the bottom of the well is improved, and the displacement effect is improved.
For steam huff-puff well operation, firstly, a phi 114mm heat insulation pipe 2-2 and a bell mouth 3-2 are put in by a central well head operation, a boiler heats steam once and then a bottom hole electric heater 6 is heated for the second time, the heat insulation pipe 2-2 is lifted out after short-term steam injection operation is carried out, then, a phi 114mm oil pipe 2-1 and a phi 120mm tubular pump 3-1 are put in by the central well head, an oil pumping unit is arranged at the well head for oil extraction production, and the process is repeated after one round of steam injection production.
The power of the control cabinet 8 is adjusted at any time according to working conditions when the steam is delivered, driven and SAGD injected, so that the electric heater 6 generates different powers to secondarily heat the steam, and the dryness of the steam at the bottom of the horizontal well is improved. The coiled tubing sealer 7 is used for steam sealing between the coiled tubing 5 with the diameter of phi 25.4mm and the coupling-free tubing 4 with the diameter of phi 48.3mm, realizes dynamic and static sealing, and does not leak.
The electric heater 6 is lowered into the well section near the bottom of the well when the well is in the vertical position.
Example 3
The pipe columns described in the embodiment 2 are applicable to the horizontal well steam injection well and the horizontal well production well, when the pipe columns are used in the horizontal well production well, the heated medium is changed into the oil well production fluid, and the production mode adopts the phi 114mm oil pipe 2-1 and the phi 120mm pipe pump 3-1 to carry out the bottom hole heating auxiliary oil extraction production.
When the viscosity of the produced fluid of the horizontal well is increased and wax is discharged, the power can be regulated by using the control cabinet 8, and the electric heater 6 at the bottom of the well is electrified and heated, so that the heating and viscosity reduction are realized, the temperature of the produced fluid at the outlet of the oil well is increased, and the yield of the horizontal well is increased. When the water content of the produced fluid is large, the well production can be stopped, the high-power output of the control cabinet 8 is regulated, the electric heater 6 is electrified to heat the produced fluid at the bottom of the well, so that high-temperature water or steam is produced, a hot water flooding or steam huff-puff effect is produced on the oil layer, and the well production is started after a period of time.
When the oil well liquid production is obviously insufficient and the oil content is reduced, the phi 120mm tubular pump 3-1 can be operated, the steam is injected into the horizontal well bottom through the phi 114mm heat insulation pipe 2-2 and the bell mouth 3-2 of the production pipe column of the phi 114mm oil pipe 2-1, the steam huff and puff operation is carried out, and meanwhile, the electric heater 6 at the well bottom is powered on and heated by utilizing the control cabinet 8 to adjust the power, so that the steam injection can be heated, the dryness of the well bottom steam is improved, the oil well liquid produced after the production pipe column of the phi 120mm tubular pump 3-1 and the phi 114mm oil pipe 2-1 is heated, the temperature of the oil well produced liquid is improved, the heating auxiliary oil extraction is realized, and the oil reservoir recovery degree and the utilization degree are improved.
Example 4
The use of each of the tubing strings described in example 2 in side bottom water reservoir heating assisted oil recovery:
When double horizontal well operation or straight and flat combined well construction is implemented, the electric heater 6 is put into the bottom horizontal well 27 through the cover layer 30, inserted into the side bottom water layer 20, heated and evaporated on the side bottom water layer 20 through high-power heating of the control cabinet 8, the functions of hot water flooding and steam flooding are exerted, the upper oil layer 14 is heated and driven to displace oil, and oil production and production are carried out through the oil layer horizontal well 29. The upper oil layer 14 can be heated by adding several groups of bottom horizontal wells 27 and electric heaters 6 on the side bottom water layer 20 according to the block geological process, and the existing vertical well 28 or a plurality of vertical wells 28 are used for oil extraction production.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (5)
1. The downhole steam secondary electric heating pipe column is characterized by comprising a continuous oil pipe (5) and an electric heater (6), wherein the continuous oil pipe (5) is provided with a cable core a (9), and the electric heater (6) is provided with a cable core b (15) and a heating wire (19) connected with the cable core b (15); the head end of the cable core a (9) is connected with a three-phase power supply of the control cabinet (8), the tail end of the cable core a is connected with the cable core b (15), and current is transmitted to the heating wire (19) for heating through the cable core a (9) and the cable core b (15) after the three-phase power supply is electrified;
The coiled tubing (5) comprises a coiled tubing body (12), a cable core a (9), an insulator a (11), an upper seal head (10) and a lower seal head (13), wherein at least one cable core a (9) penetrates into the coiled tubing body (12), and the insulator a (11) is fully distributed between the cable core a (9) and the coiled tubing body (12); the upper seal head (10) and the lower seal head (13) are respectively arranged at two ends of the continuous pipe body (12) and are used for sealing the insulator a (11);
The electric heater (6) comprises a protective tube (17), a cable core b (15), a heating wire (19), an insulator b (18) and a sealant (16), wherein one end of the protective tube (17) is closed, the other end of the protective tube is open, and the open end of the protective tube is connected with the tail end of the continuous tube body (12); at least one cable core b (15) penetrates into the protective tube (17), one end of the cable core b (15) is connected with the tail end of the cable core a (9), the other end of the cable core b is connected with the heating wire (19), and the heating wire (19) is positioned at the closed end of the protective tube (17); an insulator b (18) is distributed among the cable core b (15), the heating wire (19) and the protective tube (17); the sealant (16) is connected with the open end of the protective tube (17) and is used for sealing the insulator b (18);
the exterior of the coiled tubing (5) is sleeved with a non-coupling tubing (4) for protection; a coiled tubing sealer (7) for steam sealing is arranged between the head end of the coiled tubing (5) and the head end of the non-coupling oil pipe (4);
The heating method of the underground steam secondary electric heating pipe column comprises the following steps: the wellhead adopts an eccentric wellhead mode, firstly, an eccentric wellhead is used for descending a coupling-free oil pipe (4) in a nine-inch sleeve (1) for operation, and the coupling-free oil pipe is always descended into the initial position of a horizontal section of a horizontal well; then, a coiled tubing (5) and an electric heater (6) are put into the non-coupling oil pipe (4) by using a coiled tubing injection device; then the central wellhead operation is carried out to put into the heat insulation pipe (2-2) for steam injection operation, the control cabinet (8) is used for controlling the electric heater (6) to heat and controlling the power to carry out secondary heating on the steam at the bottom of the well;
The coiled tubing sealer (7) comprises an upper connector (22), a middle connector (23), a lower connector (25), an upper sealing packing (21) and a lower sealing packing (24), wherein the upper connector (22) is in threaded connection with the middle connector (23), the upper sealing packing (21) is arranged in the middle connector (23), and one end face of the upper sealing packing (21) is in contact with the end part of the upper connector (22); the middle connector (23) is in threaded connection with the lower connector (25), a lower sealing packing (24) is arranged in the lower connector (25), and one end surface of the lower sealing packing (24) is contacted with the end part of the middle connector (23); the outer wall of the lower connector (25) is provided with threads (26), the non-coupling oil pipe (4) is connected with the lower connector (25) through the threads (26), and the continuous oil pipe (5) penetrates into the upper connector (22), the middle connector (23), the upper sealing packing (21), the lower connector (25) and the lower sealing packing (24) and then enters the non-coupling oil pipe (4);
The continuous pipe body (12) is made of 316L stainless steel, the cable core a (9) is made of oxygen-free copper, the insulator a (11) is made of magnesia powder, the upper end socket (10) and the lower end socket (13) are made of epoxy resin, the protection pipe (17) is made of 825 alloy steel, the heating wire (19) is made of nickel-chromium, the cable core b (15) is made of oxygen-free copper, the insulator b (18) is made of magnesia powder, and the sealant (16) is made of epoxy resin.
2. A downhole steam secondary electric heating pipe column according to claim 1, wherein the whole coiled tubing (5) is resistant to 600 degrees and 25MPa; the power of the electric heater (6) is 400 kilowatts, the integral temperature resistance is 600 ℃, and the pressure resistance is 25MPa; the whole continuous oil pipe sealer (7) has 320 ℃ resistance and 25MPa resistance.
3. A downhole steam secondary electric heating pipe column according to claim 1, wherein after steam injection operation, a heat insulation pipe (2-2) is provided, an oil pipe (2-1) and a tubular pump (3-1) arranged at the tail end of the oil pipe (2-1) are put into a central wellhead, and an oil pumping unit is arranged at the central wellhead and communicated with the oil pipe (2-1) for oil extraction production.
4. A downhole steam powered secondary electric heating pipe string as defined in claim 1, further comprising: and a central wellhead down-going sampler is used for sampling and testing the dryness of the well bottom, and a control cabinet (8) is used for adjusting the power of the electric heater (6) in real time according to the dryness value.
5. A downhole steam secondary electric heating pipe string according to claim 1, wherein the end of the heat insulating pipe (2-2) is provided with a flare (3-2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111358907.1A CN114135262B (en) | 2021-11-17 | 2021-11-17 | Underground steam secondary electric heating pipe column and heating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111358907.1A CN114135262B (en) | 2021-11-17 | 2021-11-17 | Underground steam secondary electric heating pipe column and heating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114135262A CN114135262A (en) | 2022-03-04 |
| CN114135262B true CN114135262B (en) | 2024-05-07 |
Family
ID=80389748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111358907.1A Active CN114135262B (en) | 2021-11-17 | 2021-11-17 | Underground steam secondary electric heating pipe column and heating method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114135262B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202954771U (en) * | 2012-12-04 | 2013-05-29 | 刘庆敏 | Injection-production integrated unthreaded rod sealer |
| CN203515532U (en) * | 2013-08-30 | 2014-04-02 | 中国石油天然气股份有限公司 | Downhole electric heating device of continuous tube type horizontal well |
| CN110984936A (en) * | 2019-12-23 | 2020-04-10 | 中国石油大学(华东) | Preheating method for improving single horizontal well SAGD (steam assisted gravity drainage) exploitation efficiency |
| CN111322045A (en) * | 2020-03-03 | 2020-06-23 | 西南石油大学 | Method for improving steam dryness at bottom of deep well heavy oil well by electric heating |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014047469A2 (en) * | 2012-09-20 | 2014-03-27 | Pentair Thermal Management | Downhole wellbore heating system and method |
| CA2964602A1 (en) * | 2016-04-14 | 2017-10-14 | Conocophillips Company | Deploying mineral insulated cable down-hole |
-
2021
- 2021-11-17 CN CN202111358907.1A patent/CN114135262B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202954771U (en) * | 2012-12-04 | 2013-05-29 | 刘庆敏 | Injection-production integrated unthreaded rod sealer |
| CN203515532U (en) * | 2013-08-30 | 2014-04-02 | 中国石油天然气股份有限公司 | Downhole electric heating device of continuous tube type horizontal well |
| CN110984936A (en) * | 2019-12-23 | 2020-04-10 | 中国石油大学(华东) | Preheating method for improving single horizontal well SAGD (steam assisted gravity drainage) exploitation efficiency |
| CN111322045A (en) * | 2020-03-03 | 2020-06-23 | 西南石油大学 | Method for improving steam dryness at bottom of deep well heavy oil well by electric heating |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114135262A (en) | 2022-03-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106801598B (en) | Device and method for burning mixed-phase superheated steam underground | |
| CN101539011B (en) | Fire flood eclectic ignition device | |
| CN106884638B (en) | A kind of In Situ Heating method of coal bed gas heating exploitation | |
| US5539853A (en) | Downhole heating system with separate wiring cooling and heating chambers and gas flow therethrough | |
| CN106437669B (en) | A kind of thermal cracking seam method and system for deep hot dry rock formation production | |
| CA2790597C (en) | Device and method for the recovery, in particular in-situ recovery, of a carbonaceous substance from subterranean formations | |
| CN106168119A (en) | Downhole electric heating horizontal production well tubular column structure | |
| US4378846A (en) | Enhanced oil recovery apparatus and method | |
| CN102979493A (en) | Gas injection system for combustion of oil in-situ under super-critical pressure and gas injection method thereof | |
| CA3080196A1 (en) | Heavy oil steam injection method using downhole supercritical water combustion | |
| CN107575199A (en) | A kind of implementation of underground continuous oil pipe implement | |
| CN203515532U (en) | Downhole electric heating device of continuous tube type horizontal well | |
| CN110145287A (en) | A kind of compound oil extraction system of heavy oil heating viscosity reduction | |
| CN106996285A (en) | Underground mixed phase heated fluid generator and its application method | |
| CN106304446A (en) | A kind of borehole fluid electric heater | |
| CN106996283A (en) | The oil production method of spontaneous mixed phase hot fluid under a kind of hydrothermal cracking surge well | |
| CN111322045A (en) | Method for improving steam dryness at bottom of deep well heavy oil well by electric heating | |
| CN205743888U (en) | A kind of Mobile underground electric ignition and the same examining system of optical fiber temperature and pressure | |
| CN208168849U (en) | A kind of downhole fluid electric heater | |
| CN112796726B (en) | Underground blasting device and method for reservoir fracture expansion of coal-bed gas well | |
| CN114135262B (en) | Underground steam secondary electric heating pipe column and heating method | |
| CN106016221A (en) | Electric heating type downhole steam generator | |
| CN103759240B (en) | Downhole electric heating steam generator | |
| CN110863808B (en) | Thickened oil exploitation method for enhancing water drive efficiency through electric heating | |
| CN103114836B (en) | A kind of Apparatus for () and method therefor of steam heavy oil heat production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |