WO2020030043A1

WO2020030043A1 - High-pressure air ramming device for oil well, and method

Info

Publication number: WO2020030043A1
Application number: PCT/CN2019/099789
Authority: WO
Inventors: 张朝纯; 张晓�; 郑毅; 曹溪; 王悦; 张忠涛; 杨智光; 高德利; 孙冰; 张凤林; 金葵; 黄弘森; 孙兴明; 韩宝忠; 文屹; 钟明; 贺群
Original assignee: 鞍山万维科技有限公司
Priority date: 2018-08-09
Filing date: 2019-08-08
Publication date: 2020-02-13
Also published as: CN108825155B; CN108825155A

Abstract

A high-pressure air ramming device for an oil well (30), and a method. The device comprises an energy storage tank (11), an air jetting pipe (5), and a collector (14). The air jetting pipe (5) extends into the oil well (30) from a wellhead (4) thereof. The energy storage tank (11) stores high-pressure air. The air jetting pipe (5) is connected to the energy storage tank (11) via a pipeline (7). The collector (14) is for collecting a liquid in the oil well (30). The method comprises a high-pressure air ramming-based oil recovery method for an oil well (30), a high-pressure air ramming-based declogging method for an oil well (30), a high-pressure air ramming-based gap unblocking method for an oil well (30), and a high-pressure air ramming-based reservoir reenergization method for an oil well (30).

Description

High-pressure gas stamping device and method for oil well

Technical field

The invention belongs to oil recovery engineering technology, and particularly relates to an oil well high-pressure gas stamping device and method.

Background technique

Except for self-injection wells, the current oil recovery technology uses 95% of the direct extraction of mechanical kinetic energy to convert liquid kinetic energy into petroleum or liquids mixed with petroleum. This is called "mechanical fluid recovery". The liquid in the reservoir depends on the underbalanced nature of the well. The flow mode enters the well to maintain balance with the production flow. Therefore this process is also called "passive" mining process. A typical device uses a pumping pump to deliver fluid from an oil well to the surface.

The common characteristic of mechanical fluid recovery is that a certain height of the liquid column must be kept in the well to submerge the pump body, otherwise serious mechanical accidents will occur, that is, the oil pump must be below the dynamic liquid level. Therefore, the determination of the mining flow is based on the dynamic liquid level, and it is necessary to ensure that the pump body is submerged. During the production process, it is necessary to prevent solids such as sand from the reservoir from entering the pump barrel to prevent pumping accidents. Settle solids such as gravel to the bottom of the well, so the extraction speed cannot be greater than the sedimentation rate of sand from the reservoir in the well. Only then will the sediment accumulate at the bottom of the well. To a certain extent, sedimentation will affect normal oil production. Desilting of oil wells will be required, and oil production will also be affected. It also represents typical traditional craftsmanship.

The fluid level in a well directly affects the production of oil wells. The smaller the dynamic fluid level is, the greater the fluid flow from the reservoir into the well, the higher the oil well production, and the geometrical increase. Because mechanical fluid recovery must maintain a sufficient level of dynamic liquid level, the production of oil wells is greatly limited. The recoverable reserves are usually 60% smaller than the proven reserves, which is the biggest pain point of mechanical fluid recovery. Moreover, under this technical background, the oil produced often does not reach 1% of the amount of liquid produced.

Because the height of the dynamic liquid level is higher than the oil reservoir, when the oil and water are co-produced in the well, because the proportion of water is greater than oil, water will press the oil in the reservoir, and the oil cannot enter the well at the same speed as water (that is, the oil well) Production casing), it will also significantly affect the fluid flow from the reservoir into the well. The phenomenon of water chasing occurs.

After the oilfield enters the middle and late stage of production, fracturing technology, acidification, chemical plugging, process water injection, polymer injection, and ternary flooding are often adopted. Water injection and injection have caused the same layer of oil and water, a large increase in bottom water, and water stringing. The cone effect is serious, and the mudstone expansion in the reservoir is high, which leads to serious deterioration of porosity and permeability. This is also a common situation in all oil fields.

In the workover project, the oilfield has entered the middle and late stage of production, and the workload of underground deblocking, dredging, plugging, casing change, frustration, casing milling, fishing, and sand burial has increased greatly. Fracturing, acidification of the process, and stress release of mudstone expansion caused by water sensitivity caused by the side-water stratification caused damage to the casing, which resulted in a large increase in casing extraction workload, and the existing workover process did not exceed the traditional process foundation, resulting in A large number of wells to be repaired, waiting for repair and resumption of production, are also affecting productivity. The backward workover process has prolonged the workover period and the cost has increased significantly.

For some unconventional energy. For example, coalbed methane, associated gas in oil production wells, and shale gas are very expensive energy sources, but mechanical fluid extraction cannot be used for mining, which is also a technical problem to be solved. Especially the associated gas in the reservoir, because it has a smaller density, is always suppressed by the natural pressure generated by the liquid column generated in the well, and cannot be released.

Summary of the invention

The purpose of the present invention is to provide a technical solution for a high-pressure gas stamping device and method for an oil well, which can improve the recovery rate and the efficiency of the oil well, and fully exploit the resources of the oil well.

In order to achieve the above object, the technical solution of the present invention is: an oil well high-pressure gas stamping device; the device includes an energy storage tank, a gas jet pipe, and a collector, and the gas jet pipe extends from the wellhead of the oil well into the oil well, and A high-pressure gas is stored in the energy storage tank, and the gas injection pipe is connected to the energy storage tank through a pipeline. The collector is a collector that collects liquid in the oil well, and the collector is connected to the wellhead of the oil well.

Furthermore, in order to better control the pressure of the high-pressure gas injected into the oil well, the air jet pipe extends into the bottom of the oil well, and the front end of the air jet pipe is provided with a pulse pressure control which opens when the set pressure is reached. The collector is connected to the wellhead casing outlet of the oil well, and the air jet pipe is connected to a high-pressure water pipe that inputs high-pressure water through a tee.

Furthermore, a preferred device configuration is that the energy storage tank is not less than 20 cubic meters, and the gas pressure in the energy storage tank is 35 MPa.

A high-pressure gas stamping oil recovery method for an oil well; the method includes:

a jet of high-pressure gas into the oil well, driving the liquid in the oil well from the outlet of the wellhead casing, the liquid is collected in the collector, and separated in the collector;

b. When the liquid level of the oil in the oil well rises to the lower boundary of the reservoir, high pressure gas is injected into the oil well again, so that the liquid in the oil well is ejected from the wellhead casing outlet, and the cycle is repeated in sequence;

Furthermore, in order to obtain better oil recovery effect and efficiency, high pressure gas is injected into the oil well from the bottom of the oil well, and the pressure of the high pressure gas is not less than twice the internal pressure of the liquid at the bottom of the oil well, and the high pressure gas is nitrogen The liquid is separated in a collector for oil, water and sediment.

An oil well oil well high pressure gas punching dredging method; the method includes:

High-pressure gas is sprayed to the bottom of the oil well to drive the liquid in the well from the wellhead; then water is added to the high-pressure gas, and the volume fraction of the high-pressure gas to water is 7: 3; water-containing high-pressure gas is sprayed to the bottom of the oil well. The water horsepower is used to drive mud and sand in the oil well from the wellhead casing. After no mud or sand is seen in the gas stream ejected from the wellhead, stop injecting high pressure gas, the high pressure gas is nitrogen; the gas flow rate in the oil well is not less than 15.24 m / s.

A method for dredging pores of a high pressure gas in an oil well; the method comprises: after the liquid level in the oil well reaches the lower boundary of the reservoir, instantaneously injecting high pressure gas to the bottom of the oil well to accelerate the liquid in the oil well and output it from the wellhead.

Furthermore, the method of instantaneously injecting high-pressure gas is to set the time from when the high-pressure gas is injected to when the liquid starts to flow out of the wellhead is the liquid output time, and the duration of the high-pressure gas injection into the oil well is the liquid. 0.7 times the output time.

A method for dredging a reservoir of high-pressure gas in an oil well; the method includes: closing the inside of an oil well's wellhead, injecting high-pressure gas into the oil well, pressing the liquid in the oil well back into the reservoir, and then opening the wellhead to release the well. High-pressure gas.

Furthermore, in order to better unblock the reservoir, the high-pressure gas pushes the liquid in the reservoir in the opposite direction. When the pressure of the high-pressure gas in the oil well reaches the highest value, the high-pressure gas in the well is quickly released, so that The liquid and various pollutants in the reservoir are ejected out of the wellhead with the gas; the high pressure gas is repeatedly injected and released into the oil well in a pulsed manner.

The beneficial effect of the present invention is that the gas jet oil recovery method can replace mechanical liquid recovery without the need to maintain a dynamic liquid level in the oil well. The gap-type high-pressure gas jet can keep the reservoir in the oil well with good porosity and permeability. After the oil production is completed, a low-pressure cavity without liquid is formed in the oil well, so that the liquid mixed with oil and water can enter the oil well more smoothly, which can greatly increase the flow rate of the liquid in the reservoir into the well and significantly improve the efficiency of oil production; high-pressure gas injection It can avoid the occurrence of bottomhole sediments and significantly improve the maintainability of oil wells; high-pressure gas jet oil recovery also provides technical conditions for the collection of combustible gas in oil wells; gas jet dredging methods can efficiently complete bottomhole dredging and significantly improve The dredging effect can dredge the pores between the oil well and the reservoir, and dredge the pores of the reservoir geology in a large area, which can significantly improve the efficiency of the liquid in the oil reservoir's clear reservoir to enter the well, and significantly increase the productivity of the well.

The present invention is described in detail below with reference to the drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a system diagram of a high-pressure gas stamping device for an oil well according to the present invention;

FIG. 2 is a schematic diagram of an oil well structure according to the present invention.

The symbols in the figure are: salvage tool 1, pulse pressure controller 2, downhole drilling tool 3, wellhead 4, drill pipe 5 (i.e. jet pipe), jet pipe joint 6, high pressure pipe 7, tee 8, high pressure pump truck 9 , Control valve 10, accumulator 11, energy storage check valve 12, wellhead tee 13 (that is, the wellhead casing outlet connected to the collector), collector 14, gas detector 15, automatic ignition device 16, air pressure Machine 17, overhaul vehicle 18, safety valve 19, screw conveyor 20, platform 21, rotary self-sealing device 22, wellhead blowout preventer 23 and exhaust pipe 24, high-pressure water pipe 25, oil well 30, oil reservoir 31, Oil 32. Water 33 entering the oil well. L is the bottom depth of the oil well, L1 is the height from the liquid surface to the bottom of the well when the liquid surface is in static equilibrium, and L2 is the height of the lower boundary of the reservoir.

detailed description

Embodiment one:

As shown in FIG. 1, an oil well high-pressure gas stamping device includes an energy storage tank 11, a gas injection pipe 5, and a collector 14.

The energy storage tank 11 includes a plurality of connected high-pressure gas tanks. The pressure and capacity of the energy storage tank should meet the oil production and maintenance needs of the oil well. In this embodiment, the design pressure of the energy storage tank is 35 MPa, and the capacity of the energy storage tank is 20 cubic meters. The high-pressure gas in the energy storage tank is compressed air or nitrogen. The energy storage tank is provided with a safety valve 19.

The gas injection pipe is an oil pipe extending into the oil well 30, and the inner hole of the oil pipe serves as a passage for high-pressure gas. The collector 14 is a fully enclosed large tank with a function of automatically separating gas, water, and oil.

The lower end of the gas injection pipe (tubing) 5 is connected to the downhole drilling tool 3. The lower end of the downhole drilling tool 3 is installed with a pulse pressure controller 2. The pulse pressure controller is a check valve that opens when the set pressure is reached. The lower end of the pulse pressure controller is connected. A fishing tool 1 with a perforation is provided with a conventional drilling tool, a wellhead blowout preventer 23, a wellhead big cross 13 and a rotary self-sealing device 22 on the wellhead 4 in this order; the oil pipe 5 protrudes upward and the upper end of the oil pipe 5 passes through The gas injection pipe joint 6 is connected to a high-pressure pipe 7. The oil pipe 5 is pulled up by the overhaul vehicle 18 and protrudes from the platform 21 of the oil well. The high-pressure pipe 7 is connected to the tee 8, and one end of the tee 8 is connected to the high-pressure pump truck 9 through a high-pressure water pipe 25. The high-pressure pop-up is responsible for supplying high-pressure water. The other end of the tee 8 is connected to a pressure sensing control valve 10. The control valve 10 is connected to an accumulator 11 and is responsible for gas supply. An energy storage check valve 12 is also provided between the control valve 10 and the tee 8. . The accumulator 11 is provided with a safety valve 19.

The wellhead big cross 13 is used as an interface between the wellhead and the collector 14. The wellhead big cross 13 is connected to the collector 14 through a water hose 26 to prevent the gas, water, oil, and sand returned from the well from contaminating the ground environment. A gas detector 15 and an auto-ignition device 16 for detecting methane and hydrogen sulfide are provided on the exhaust pipe 24 of the device 14. When toxic or flammable and explosive gases exceed the standard, it can automatically ignite to eliminate its hazards and ensure normal construction. Perform; the accumulator 11 is connected to the air compressor 17, the air compressor pressurizes the gas in the accumulator 11 so that it reaches a set pressure. The collector 14 is provided with a screw conveyor 20 for discharging solid materials.

The pulse pressure controller 2 is a device with a full mechanical structure, without electrical components and a power source, and is used to control the pressure of the high-pressure gas input to the bottom of the oil well. Because the depth of an oil well is usually more than 1 km, and the diameter is usually not more than 200 mm. Due to the long-distance high-speed transmission, it is difficult to control the actual pressure of high-pressure gas input into the well from the ground, and electrical appliances are not allowed in the oil well. Equipment and cables (electrical components may cause flammable gas explosions in oil wells), so the pulse pressure controller without electrical components and power supply can effectively control the actual pressure of the high-pressure gas input into the well (lower limit value of control pressure) .

As shown in FIG. 2, in this embodiment, a 7-inch production casing is produced by an oil well, the bottom depth L of the oil well is 1500 m, and the internal volume of the oil well is about 160 cubic meters; in the state of liquid surface equilibrium, the liquid surface reaches the bottom of the well. The height L1 is 400 m (the liquid level equilibrium state is the liquid level in an oil well in a natural state. Due to the formation pressure, the liquid level is usually higher than the upper boundary of the reservoir 31 when the liquid level is in static equilibrium.) The liquid in an oil well mainly includes petroleum, water, and gas. In order to facilitate calculation and obtain safer parameters, the density of water is used as the density of the liquid in the oil well. Therefore, the internal pressure of the well bottom liquid is 400m × 1000kg / m ³ = 400000kg / m ² ≈4.0 MPa. In order to ensure that the high-pressure gas can drive the liquid in the oil well, the pressure of the high-pressure gas input to the bottom of the oil well must not be lower than 4.0 MPa (gas lift pressure during gas lift oil recovery)

High-pressure gas includes high-pressure air and high-pressure nitrogen. The high-pressure air is compressed by the air compressor into the energy storage tank. High pressure nitrogen can come from a nitrogen generator and pressurized by an air compressor, or from a high pressure nitrogen bottle.

Embodiment two:

An oil well high-pressure gas stamping oil recovery method. This embodiment is an oil recovery method of the oil well high-pressure gas stamping device according to the first embodiment. The process includes:

a. High-pressure gas is injected into the oil well to drive the liquid in the oil well to be ejected from the outlet of the wellhead casing, and the liquid is collected in a collector and separated in the collector. The high-pressure gas is nitrogen stored in an energy storage tank. The source of nitrogen gas comes from a nitrogen generator.

With reference to the oil well high-pressure gas stamping device according to the first embodiment, the specific operation is: turning on the air compressor to pressurize the energy storage tank. The calculation method of the pressure in the energy storage tank is: First, according to the pressure of the high-pressure gas is not less than twice the internal pressure of the well bottom liquid, according to the calculation in the first embodiment, the internal pressure of the well bottom liquid is 4.0 MPa (level balance The highest value in the state), the pressure of the high-pressure gas should not be less than 8MPa. The volume of the energy storage tank is 20 cubic meters. The gas in the energy storage tank can store 1,600 cubic meters of nitrogen at normal pressure under the pressure of 8 MPa. In order to ensure a sufficient high-pressure gas source, the amount of gas output by the energy storage tank (in general Pressure state meter) should be no less than 12 times the internal volume of the oil well, and the internal volume of the oil well is 160 cubic meters, that is, 1920 cubic meters. Therefore, the total amount of air in the energy storage tank (under normal pressure) is 1600 cubic meters + 1920 cubic meters. = 3520 cubic meters. In a 20 cubic meter energy storage tank, 3520 cubic meters of nitrogen can be stored under a pressure of 17.6 MPa. When the pressure value is higher between 8MPa and 17.6MPa, the lower limit of the pressure value in the energy storage tank is 17.6MPa.

When the pressure value in the energy storage tank reaches the lower limit, the control valve opens, and the high-pressure gas is forced to open the pulse pressure controller through the inner channel of the oil pipe. The liquid inside is ejected from the wellhead and enters the collector. If the oil well contains flammable gas, the high pressure gas drives the flammable gas in the oil well to be ejected from the wellhead with the liquid and enters the collector. When all the liquid in the oil well has been ejected (or there will be no more liquid in the gas stream ejected from the wellhead), stop injecting high pressure gas into the oil well.

The liquid in the oil well is collected in a collector and separated in the collector.

b. When the liquid level in the oil well rises to the lower boundary of the reservoir (as shown by L2 in Figure 2), high pressure gas is injected into the oil well again to drive the liquid in the oil well to eject from the wellhead, enter the collector, and repeat in sequence. cycle. After step a, the liquid in the oil well is output. Under the effect of formation pressure and other factors, the liquid in the reservoir 31 will continue to seep into the oil well, so that the liquid level in the oil well will gradually rise, as shown in FIG. 2. The rate of liquid seepage into the oil well from the reservoir gradually slows down. If the liquid in the oil well reaches the liquid surface equilibrium height and then the high-pressure gas injection is used for oil recovery, the interval between gas injection and oil recovery will be increased, and the liquid column will be suppressed. The oil feed rate reduces the efficiency of oil recovery. If high pressure gas injection is performed when the liquid level in the oil well is low, the oil production of a single high pressure gas injection will be reduced, excessive high pressure gas resources will be consumed, and the cost of oil production will increase. According to engineering practice and research, when the liquid level in the oil well rises to the lower boundary of the reservoir, high-pressure gas jet oil recovery is performed again, which has higher oil recovery efficiency and lower oil recovery cost, which is a better technical solution.

The liquid collected in step a and step b is a mixed liquid of oil and water containing grit, and petroleum, water, grit, and combustible gas are precipitated and separated in a collector.

At present, except for self-blowing wells, 95% of oil wells use the mining technology that directly converts liquid energy into mechanical energy to extract petroleum and various liquids. The device process can be called "mechanical liquid recovery". The common characteristic of mechanical fluid recovery is that a certain level of liquid level must be kept in the well to submerge the pump body, otherwise serious mechanical accidents will occur.

Typical equipment for mechanical fluid extraction includes hoe, deep well pump, and downhole structural rod pump. The principle is that the liquid is discharged from the well out of the well through the under-balanced means in the well through the lifting function of the liquid by the machine. The underbalance in the well means that the liquid pressure in the oil well is in a state of equilibrium with the liquid pressure in the formation surrounding the oil well, so that liquid flows between the oil well and the formation, especially the liquid pressure in the reservoir is greater than the liquid in the oil well. Under pressure, the liquid seeps from the reservoir to the well. This process is also known as a “passive” mining process, because it needs to rely on the natural pressure in the reservoir and the ability to maintain fluid balance in the well to generate flow. In the well, a dynamic fluid level in the well that is under-balanced in the well is maintained. The liquid in the oil layer flows into the oil well.

According to the basic theory of fluid dynamics, any liquid has a cumulative pressure (also known as the natural pressure of the liquid). Different depths in the liquid have different cumulative pressures, and the value is the product of the density and depth of the liquid. If they are both liquids (such as oil and water) and have different specific gravity, the total pressure should be calculated in layers. The distribution is in accordance with the law of light up and down.

The premise of using mechanical fluid recovery is that a certain height of liquid column must be kept in the well. The determination of the production flow is based on ① the dynamic liquid level must ensure that the pump body is submerged in it; ② the natural sedimentation speed of solids such as sand production in the reservoir must be offset in the pumping flow velocity to ensure that sandstone cannot enter the pump barrel to prevent it from occurring Pump accident. With these two points, determine the dynamic liquid level height (called the optimal liquid collection parameter). Because the height of the liquid column is calculated from the upper boundary of the oil reservoir as the starting point, when oil and water are co-produced in the well, the water is at the bottom and the oil is at the top. This shows that water at the exit of the perforation section of the reservoir always suppresses the oil in the reservoir from entering the well with the same speed as water. Although oil and water are both liquids, they are successively entered into the well due to their specific gravity. It is a natural law to weigh more and lighter. Because the well has a dynamic liquid level, it determines that the pressure inside and outside the oil well is in a balanced state, not that the pressure outside the oil well is strong, but the pressure inside the oil well is small. The amount of fluid produced by this well is related to the height of the liquid column in the well. The smaller the liquid column height is, the higher the production is, and it increases geometrically.

Simply pursuing an increase in liquid production is a misunderstanding. The key is to determine the water production. If the water output is 100 tons per day, increase the pump's displacement to 200 tons so that the liquid level cannot be generated in the well at this time. At this time, the gates of the perforation section are opened to allow the oil and water to compete with each other. There will be no water blocking. phenomenon. Water blocking is the main reason why the recoverable reserves of oil wells are 60% smaller than the proven reserves. As long as the mechanical pump is used, the principle must not be violated, and the liquid column must be retained. This is the biggest pain point when using a mechanical pump. At present, the major oilfields produce less than 1% of the volume of liquid produced under this technical background.

As far as the state of reservoirs in the middle and late stages of the oilfield is concerned, in the early stages of the development, the natural pressure of the original formation had been released and most of the blocks had entered the equilibrium stage. Gradually withdrawn from the blowout well, the oil production project has been put to the test. At this time, a large number of self-blowing-to-mechanical oil recovery technologies emerged. Electric submersible pumps are widely used due to their considerable displacement. Progressive cavity pumps are used due to their relatively large sand production. Pumping units and deep well pumps have been used so far. When the development entered the middle and late stages, the electric submersible pumps were gradually abandoned (due to the decrease in fluid production), which proved that the oilfield was moving towards a decay period. In order to extend the mining time, various oilfields vigorously carry out the development of new blocks, drill new wells, drill infill wells, adjust wells, and horizontal wells, and adopt fracturing processes, acidification, chemical deblocking, process water injection, polymer injection, ternary flooding, etc. The measures did not stop the reality of production loss and no new blocks were available, but they greatly increased the cost of oil production.

In China, there is no place to drill infill wells in the old block, the cost of drilling horizontal wells is too high, and the gap between input and output is too small, resulting in a large number of shallow traditional well teams waiting for employment. The fracturing process actually sees immediate short-term benefits, sacrifices long-term benefits and may cause secondary disasters. The fracturing fractures increase the oil flow passage once the initial period is passed, and the effect is worse than the original. In addition, the outer cement ring damages the water string and causes the mudstone to expand. This expansion stress will cause the casing to deform from light to heavy. Frustrated. At present, such large workovers are increasing at a rate of 20% per year, which affects a large number of oil wells that cannot produce normally. Acidification and deblocking, because the formation absorption is too large, the injection volume is not enough, and the affected area is limited. Water injection and polymer accumulation cause the same layer of oil and water, a large increase in the bottom water, and serious water cone water cone consequences. The mudstone in the reservoir has a high incidence of expansion, leading to severe deterioration of porosity and permeability. This is also a common practice in various oil fields.

In drilling engineering, in order to prevent water striations in each layer, the cementing quality is strictly required, and the drilling qualification rate is measured by the cementing quality, but the problem of the same layer of oil and water cannot be solved. It is also impossible to solve the problem of artificially retaining the liquid column in the well when using mechanical oil production. Therefore, changing the method of mechanical oil recovery is the top priority for solving the remaining oil in the reservoir.

Larger wells than unconventional energy sources, low pressure, high water cut, and easy sand production, such as coalbed methane, associated gas in shale gas production, shale gas, and other very expensive energy mining problems have not been completely solved in the world, especially The coal seam gas net mining project affects the production safety of a large number of coal mines and the comprehensive utilization of coal seam gas. There is an urgent need for a process capable of net mining to release this part of production capacity as soon as possible.

According to the principles of aerodynamics, fluid dynamics, and engineering mechanics in a specific environment formed by artificial control, the present invention combines basic theory with the current “passive” mining method of mechanical energy, and changes it into a “negative pressure vacuum” of aerodynamic energy. Intelligent integration of "passive" and "active" mining dredging and deblocking.

(1) Characteristics of aerodynamic energy:

First, the mechanical energy is converted into aerodynamic energy (performed on the ground), and the energy is stored in a compressed high-pressure gas in an energy storage tank. Gas has the characteristics of compressibility, throughput, energy storage, rapid use, no accumulated pressure, and explosiveness. Driven by the same energy, the gas flow rate can be more than one thousand times the liquid flow rate, and the density of the gas is liquid. (Clear water) 1/800, when the same power as the liquid, the amount of occurrence is 10 times the liquid. When the gas velocity reaches 15.24 meters per second, it can carry solid sandstone. Vacuum can be generated during gas lift and liquid movement (difference in gas-liquid density when gas lift generates flow rate). The strength of the vacuum is proportional to air pressure, flow rate, and flow rate (not limited by depth). It can generate resonance during pulses, and the reaction force can be ignored. Excluded (under gas under-equilibrium conditions). The permeability of air permeation is one hundred times that of liquids, and the penetrability is strong, while liquids are incompressible and accumulate energy, have a cumulative pressure, and liquids cannot burst.

According to the above-mentioned basic theory, after control, it can break through the vacuum suction and deblocking of negative pressure, non-pump mixed production, integrated same production, and multiple separation and treatment processes on the ground for oil and gas production.

The gas injection oil production method of the oil well in this embodiment no longer needs to maintain a dynamic liquid level in the oil well, nor does it need a mechanical pump, and there is no risk of failure of the mechanical pump when the dynamic liquid level is exposed. The situation of water-suppressed oil and gas has been completely changed. According to the design, the production volume can reach tens of thousands of cubic meters. At the same time, in the process of oil production, the effect of desilting and plugging can be produced, and the liquid in the reservoir layer can be smoothly flowed into the oil well, and the oil and gas can be produced at the maximum speed and flow rate.

Embodiment three:

A high-pressure gas punching and dredging method for oil wells. This embodiment is the dredging method of the oil well high-pressure gas stamping device according to the first embodiment, and the process includes:

High-pressure gas is sprayed to the bottom of the oil well to drive the liquid in the well from the wellhead; then water is added to the high-pressure gas, and the volume fraction of the high-pressure gas to water is 7: 3; water-containing high-pressure gas is sprayed to the bottom of the oil well. The water horsepower is used to drive mud and sand in the oil well from the wellhead casing. After no mud or sand is seen in the gas stream ejected from the wellhead, stop injecting high-pressure gas, which is nitrogen; the gas flow rate in the oil well is not less than 15.24 m / s.

In combination with the oil well high-pressure gas stamping device according to the first embodiment, the operation method is: firstly spray high-pressure gas to the bottom of the oil well to drive the liquid in the oil well from the wellhead; the oil well high-pressure gas punching method described in the second embodiment can be used After the above operations are completed, the gas pressure in the oil well is under gas equilibrium.

Then the high-pressure pump truck starts water supply, and the ratio of the volume fraction of high-pressure nitrogen to water is 7: 3, that is, the ratio of the volume of compressed high-pressure air to the volume of water is 7: 3.

Water and high-pressure gas are mixed and injected into the inner hole of the oil pipe (ie, gas jet pipe), and the high-pressure gas containing water is sprayed into the bottom of the well through the inner hole channel of the oil pipe to dredge the well. The water in the high-pressure gas can strengthen the impulse and the flow rate of the water-containing gas. No less than 15.24 m / s, which can generate water horsepower for mud and liquid downhole. The volume of solid and liquid in the oil well is less than 30% of the volume of gas. The gas-water mixture injected during the upward movement is discharged out of the well in a gasified form.

Under normal circumstances, the greater the internal pressure of the well bottom fluid, the denser the sediment at the bottom of the well and the higher pressure gas is required to remove it. In order to ensure the dredging effect, according to experience, the pressure of the high-pressure gas injected into the oil well should not be less than twice the internal pressure of the bottom fluid in the oil well. As described in Example 1, the internal pressure of the bottom fluid in the oil well is 4.0 MPa. High pressure gas of MPa for dredging will get better results.

Because there may be combustible gas such as methane downhole, high-pressure air contains oxygen, sandstone in the well will generate static sparks when it frictions with the steel pipe on the wall of the well during high-speed movement. At this time, there are all three elements of fire and explosion. When the methane concentration exceeds 15.5%, an explosion accident may occur. If nitrogen is injected instead of air, the cost will be high. Therefore, the scientific method is to inject air and water into the well to generate gasified water, which can completely eliminate the generation process of the static phenomenon, and the safety issue is guaranteed. This method is generally not applicable to oil wells with mechanical fluid production. Correspondingly, the oil well described in the second embodiment can only be stopped, and the pump is checked for sand flushing and dredging.

Embodiment 4:

A method for dredging pores of oil well high pressure gas punching. This embodiment is the pore dredging method of the oil well high pressure gas punching device according to the first embodiment. The method is used for dredging percolation pores between an oil well and a reservoir. The process includes:

After the liquid level in the oil well reaches the lower boundary of the reservoir, the high-pressure gas is instantaneously injected into the bottom of the oil well, so that the liquid in the oil well gains acceleration and is output from the wellhead.

The method for instantaneously injecting high-pressure gas is to set the time from when the high-pressure gas is injected to when the liquid begins to flow out of the wellhead is the liquid output time, and the duration of the high-pressure gas injection into the oil well is 0.7 times the liquid output time. That is, the expansion force of the liquid released by the high-pressure gas and the motion inertia of the liquid move upwards within 30% of the later period.

After the above process is completed once, the liquid in the reservoir will seep into the well. When the liquid level in the oil well reaches the lower boundary of the reservoir, the high pressure gas is instantaneously injected again to the bottom of the oil well, so that the liquid in the oil well is ejected from the wellhead, and this step is repeated several times until the downhole dredging is completed. According to practical experience, for ordinary oil wells, a good dredging effect can be obtained by performing 5 to 10 high-pressure gas injection processes.

In this method, the high-pressure gas drives the liquid in the oil well to move toward the wellhead with high acceleration, and the liquid with high acceleration can move upward in the overall form, and is finally discharged from the wellhead. During this movement, when the injection of high-pressure gas is stopped, the liquid in the oil well will continue to move upwards with inertia, which can cause a "liquid piston" effect, which causes a vacuum effect at the bottom of the well, that is, the pressure in the oil well is greatly increased. Below the pressure of the reservoir outside the oil well, the liquid in the reservoir will get a greater driving suction force into the oil well, and the mud leaking into the reservoir during drilling and the fines in the reservoir close to the well will be fine. The sediment of sandstone has a flushing effect, the mud and sediment will be removed, and the seepage pores between the oil well and the reservoir will be cleared.

This method is based on the principle that when the liquid column generated by the lower boundary of the reservoir in the well passes a rapid gas lift, the liquid column can be quickly raised from the bottom of the well to the wellhead. The difference in liquid density is 800 times that of gas and gas can be generated. The characteristics of explosive force and the density of gas are the characteristics of liquid 1/800, which can make the liquid column form a piston function and form a vacuum suction phenomenon. Due to the low gas density and the feature of no cumulative pressure, solid sandstone and liquids downhole can enter the well. When acceleration occurs in the liquid column in the well (liquid column inertia occurs), the gas lift pressure at the lower part of the liquid column in the well will cause negative pressure. At this time, the air supply valve is closed to stop the gas supply, and the liquid column inertia force is exerted to the extreme.

Embodiment 5:

A method for dredging an oil well high-pressure gas punching reservoir. This embodiment is a method for dredging an oil reservoir of an oil well high-pressure gas punching device according to the first embodiment.

First, the inside of the well head is closed. Then high-pressure gas is injected into the oil well, so that the liquid inside and outside the oil well is pressed back into the reservoir, and some high-pressure gas is also pressed into the reservoir, and then the wellhead is quickly opened to release the high-pressure gas in the well. Driven by the pressure in the reservoir, the gas in the reservoir is discharged into the oil well with the liquid and water-sensitive mud cake, and this step is repeated multiple times. Each high-pressure gas pulse can increase the pore throat in the original pore foundation in the reservoir, and can unblock formation pores in a larger range of reservoirs. After that, the bottom of the well can be dredged by the high-pressure gas punching and dredging method of the oil well described in Embodiment 3, or the method of Embodiment 2 is used for oil production, and the bottom of the well can be cleaned during the oil production process.

A higher pressure is required in this process, and the pressure of the high-pressure gas should be kept not less than 30 MPa. In this embodiment, the high-pressure gas is brought to the upper limit of the design pressure of the energy storage tank of 35 MPa.

The principle of this method is to increase the pore throat and permeability coefficient in the reservoir by using the characteristics of gas compressibility, explosion, and swallowability.

At present, in conventional downhole dredging, flushing, and deblocking operations in oilfields at home and abroad, a process is generally adopted in which a liquid circulation is established in the well after the liquid is pumped to return the mud and sand in the well to the surface. The process has the following drawbacks:

Because the liquid has a cumulative pressure of liquid, the internal pressure of the liquid is proportional to the specific gravity of the liquid and the depth of the liquid. There is a large internal pressure of the liquid in the wells of several kilometers, and the increase of the pumping flow can only improve the carrying capacity of the fluid, and cannot cause the fluid to spray upwards in the liquid at a long distance. Only the fluid can be ejected in the gas environment. At this time, the effect of higher flow velocity and longer spray distance will appear. The following situations occur in the traditional process of sand blasting and dredging:

In the case of long-distance sand stuck after falling in the well, only the sleeve milling operation can be used. When large-diameter tools cannot be used for nest milling operations, they can only be fished upside down and washed in sections. If this happens in actual work, the salvage process of subsequent workover projects will be very complicated, which will greatly increase the workover cycle and even cause the well to be scrapped. Due to the internal pressure of the liquid in the well, the natural pressure of the formation outside the casing is balanced. Therefore, the traditional dredging process can only have a certain dredging effect in the casing well, and various pollutions in the formation outside the casing. Such as mud pollution left in the oil layer during drilling, pollution caused by silt deposition near the well, and mud cake pollution caused by water swelling in the formation caused by water injection will not have any effect. In the middle and late stages of oilfield development, casing frustrations often occur due to many factors such as prolonged water injection and acid injection operations, frequent downhole operation and construction, casing material and corrosion, and changes in the formation. The external collapse of the casing at the casing frustration can cause the upper and lower casings to be displaced, and the casing to corrode, resulting in normal oil production and the inability of working tools to pass. If this part of the mud outside the casing is not cleaned out of the well, the collar cannot be used to straighten the casing, and the casing is easily damaged. If there is severe deformation here, the lower casing cannot be found with the collar tip tool, and the solution can only be taken by taking the upper casing out of the well.

Using the methods of

Embodiments

3, 4 and 5 can not only solve the long-distance sand card, but also avoid the sleeve milling process. As long as it is not a hard card, it will also avoid all the operating processes of salvage because of the sand card. Makes the workover process very easy. On this basis, vacuum suction is generated without moving any pipe string and tools, which has a good effect on dredging outside the oil well and unblocking the target layer. The invention can clear the silt and plug the underground pipe string of all oil, water and gas wells, and remove the stuck cards. It can simultaneously perform high-speed jet impact cleaning in the well, and simultaneously vacuum the pollution outside the oil well while fishing at one time. Features. It is the most powerful, direct, easiest and most economical best oil recovery assisted process for solving dredging and plugging outside oil wells.

The technical solution of the present invention is characterized by:

I. Use high-pressure energy storage gas concentration speed to inject nitrogen into the well to make a gas lift liquid column to return the liquid up to the well. When the gas reaches an under-balance in the well, a high-pressure pump truck is forcibly injected into the gas pipeline into the well. Fresh water uses water to generate water horsepower, and in the case of gas in the well, a jet stream is generated to impact the mud at the bottom of the well. As long as the flow and velocity of air and water reach 15.24 m / s or more, the task of dredging can be completed. (The workover project can also achieve this goal).

2. Utilizing the characteristics of gas permeability being a thousand times of liquid permeability and compressible, explosive, and throughput characteristics, the wellhead passage is blocked, a large amount of gas is injected into the well through the reservoir borehole, and the reservoir is transformed by pulse resonance. The physical properties of the layer increase the pore throat, and the wellhead is discharged at regular intervals to flush various pollutants.

3. The use of rapid gas pressure to lift the accumulation of the liquid column in the lower boundary of the reservoir caused by the vacuum vacuum phenomenon, through the perforation section, the reservoir is strongly pumped for oil production, from negative pressure passive oil production to active oil production, at the same time Deslagging and dredging in one. The principle is that the density of the liquid is 800 times that of the gas. After the liquid column is lifted by high pressure gas, the liquid column will gradually accelerate, that is, the liquid column will produce a piston action. When the liquid column accelerates, the gas pressure in the well will immediately decrease to Negative pressure is displayed. At this time, the air supply valve is closed to maintain the maximum vacuum. This solution can not only maintain liquid column hedging in the reservoir section of the reservoir, but also can accelerate the fluid inflow rate without producing water to suppress oil and gas production. In order to save gas consumption, this solution can continuously store energy, guarantee that the equipment works with low power, and intermittently accumulates the liquid column in the downhole to recover oil. It can also achieve the intermittent oil recovery at the same time as the process of desilting and plugging is synchronized.

4. The use of gas oil production can make the lower boundary of the oil reservoir in the well without the need to retain the liquid column, and there is no mechanical pump in the well, so the reservoir can be completely exposed and produced under the accumulated pressure without liquid. Because of the difference in the specific gravity of water, oil, and gas, gas will enter the well first. During intermittent oil production, a vacuum pump can be installed at the wellhead to evacuate the gas to the wellhead container and then compress it. Fill the container and store it for use. When the oil is vacuumed, the concentration of natural gas in the casing ring is already very low, and the remaining gas can reach the emission standard and be discharged to the atmosphere together with the injected high-pressure nitrogen. When the discontinued period is repeated, draw. It can be achieved, the purity of natural gas in the well can reach the emission standard, and it can be fully utilized for co-production of oil and gas. The oil and gas in the well are often twin sisters. When there is oil, gas is produced. However, the pressure of the gas causes the accumulated pressure in the liquid column retained in the well to be suppressed by mechanical oil production. There is no chance to release it.

Claims

An oil well high-pressure gas stamping device; characterized in that the device includes an energy storage tank, a gas jet pipe and a collector, the gas jet pipe extends from a wellhead of the oil well into an oil well, and the energy storage tank stores high-pressure gas, The air jet pipe is connected to the energy storage tank through a pipeline, the collector is a collector that collects liquid in the oil well, and the collector communicates with the wellhead of the oil well.
The high-pressure gas stamping device for an oil well according to claim 1, characterized in that the air jet pipe extends into the bottom of the oil well, and the front end of the air jet pipe is provided with a pulse pressure which opens when the set pressure is reached. A controller, the collector is connected to a wellhead casing outlet of the oil well, and the air jet pipe is connected to a high-pressure water pipe that inputs high-pressure water through a tee.
The oil well high-pressure gas stamping device according to claim 1, wherein the energy storage tank is not less than 20 cubic meters, and the gas pressure in the energy storage tank is 35 MPa.
A high-pressure gas stamping oil recovery method for an oil well; characterized in that the method includes:

a jet of high-pressure gas into the oil well, driving the liquid in the oil well from the outlet of the wellhead casing, the liquid is collected in the collector, and separated in the collector;

b. When the liquid level of the oil in the oil well rises to the lower boundary of the reservoir, high pressure gas is injected into the oil well again, so that the liquid in the oil well is ejected from the wellhead casing outlet, and the cycle is repeated in sequence;
The method of claim 4, wherein high-pressure gas is injected into the oil well from the bottom of the oil well, and the pressure of the high-pressure gas is not less than twice the internal pressure of the liquid at the bottom of the oil well. The high-pressure gas is nitrogen; the liquid is separated into oil, water and precipitates in a collector.
A method for pressurizing and dredging a high-pressure gas in an oil well; the method includes:

High-pressure gas is sprayed to the bottom of the oil well to drive the liquid in the well from the wellhead; then water is added to the high-pressure gas, and the volume fraction of the high-pressure gas to water is 7: 3; water-containing high-pressure gas is sprayed to the bottom of the oil well. The water horsepower is used to drive mud and sand in the oil well from the wellhead casing. After no mud or sand is seen in the gas stream ejected from the wellhead, stop injecting high pressure gas, the high pressure gas is nitrogen; the gas flow rate in the oil well is not less than 15.24 m / s.
A method for dredging pores of high pressure gas in oil wells; characterized in that, the method includes: after the liquid level in the oil well reaches the lower boundary of the reservoir, instantaneously injecting high pressure gas to the bottom of the oil well, so that the liquid in the oil well is accelerated, and the fluid from the well is accelerated Output.
The method according to claim 7, wherein the method of instantaneously injecting high-pressure gas is to set the time from when the high-pressure gas is started to when the liquid starts to flow out of the wellhead. Output time, the duration of jetting high pressure gas into the oil well is 0.7 times the liquid output time.
A method for dredging a reservoir of high pressure gas in an oil well; the method comprises: putting the inside of the well head in a closed state, injecting high pressure gas into the oil well, and pressing the liquid in the oil well back into the reservoir, and then Open the wellhead to release high-pressure gas in the well.
The method for dredging a reservoir of high-pressure gas in an oil well according to claim 9, wherein the high-pressure gas pushes the liquid in the reservoir to the opposite direction, and when the pressure of the high-pressure gas in the oil well reaches the highest After the value, the high-pressure gas in the well is quickly released, so that the liquid and various pollutants in the reservoir are ejected out of the wellhead with the gas; the high-pressure gas is repeatedly injected and released into the oil well in a pulse manner.