Gas well gas-liquid underground separation down-injection and up-production method, system and operation system

Abstract

The invention provides a gas well gas-liquid downhole separation under-injection and over-production method and system and an operation system, the operation system comprises a ground production and injection pipeline, a shaft and an under-injection and over-production pipe column, and an oil sleeve annulus is formed between the under-injection and over-production pipe column and the shaft; the lower injection and production upper pipe column comprises a bypass one-way valve, a packer and a one-way valve which are sequentially connected from top to bottom; the ground production and injection pipeline comprises a tubular column pipeline, an oil sleeve pipeline and a gas production pipeline; the under-injection and over-production method comprises the following steps: step S10, emptying oil pressure; s20, normal gas production is carried out; step S30, underground water injection; in the step S10, the pipe column pipeline is communicated with the gas production pipeline, and the oil sleeve pipeline is disconnected from the gas production pipeline; in the step S20, the oil sleeve pipeline is communicated with the gas production pipeline, and the pipe column pipeline is disconnected from the gas production pipeline; in the step S30, the pipe column pipeline and the oil sleeve pipeline are communicated and are both disconnected with the gas production pipeline, or the pipe column pipeline is connected with an external pressure supply device, or pressure building is carried out, and the problem that gas well drainage gas production is difficult is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas field drainage and gas production, and in particular to a gas well gas-liquid downhole separation injection and production method, system and operation system. Background Art

[0002] During the exploration and development of gas fields, many liquid-accumulating wells have appeared. Especially in the middle and late stages of gas well production, the gas wells themselves lack energy and are unable to carry out liquid, resulting in the gas wells being drowned and unable to achieve production capacity. In addition, the production layers of some gas wells are gas and water in the same layer. When the water cannot be discharged, the gas will also be unable to be produced. In particular, the exploitation of gas layers in water-rich areas is currently a problem.

[0003] In addition, all water and liquid produced by gas wells need to be transported to specially established treatment plants or purification plants for secondary treatment before they can be reinjected into special water injection wells. The cost is high. Some gas wells are large water and atmospheric types, and it is common to produce more than tens of thousands of cubic meters of natural gas and hundreds of cubic meters of liquid every day. Sometimes it will cause the gas gathering station to fail to transport in time and shut down the well. After the well is shut down, the gas well will drown due to its own liquid accumulation.

[0004] Current drainage technologies such as gas lift, bubble drainage, plunger, velocity string, and negative pressure gas production are all unable to solve the problem of tapping the potential and resuming production of submerged gas wells. In addition, the above technologies will bring out produced fluid while producing gas, and the produced fluid needs to be processed, which has insurmountable defects.

[0005] In addition, in the current injection-down and production-up technology for gas wells, the production tubing is installed with a packer and a bypass short joint from bottom to top, a rod pump is put into the tubing, the packer isolates the casing annulus, the bypass short joint is connected to the casing annulus in one direction, and the rod pump reciprocates to pump the water in the casing annulus into the tubing in one direction. When the liquid level in the tubing rises to a certain level, as the water pressure in the tubing increases, the water in the tubing will automatically be injected into the stratum below the packer. This method has the following defects: ① There is a complex problem of pulling out the tubing string and repairing the well due to damage to the rod pump; ② As the water injection pressure in the lower layer increases, the water level in the tubing will become higher and higher, and finally the wellhead will flow by itself. Although a back pressure regulating valve can be installed on the wellhead tubing line to control it, the pressure of the back pressure regulating valve will continue to increase until it fails. Once it fails, the water injected in the early stage will continue to gush out, causing hidden dangers; ③ Carrying out the tubing string operation will cause the water injected in the well to gush out, which is difficult to control; ④ There is a problem of wear of the wellhead tubing seal of the rod pump.

[0006] In summary, in the prior art, gas wells have the technical problem that it is difficult to drain water and produce gas. Summary of the invention

[0007] The purpose of the present invention is to provide a method, system and operating system for gas well gas-liquid downhole separation injection and production, so as to solve the technical problem that it is difficult to drain water and produce gas in gas wells.

[0008] The above-mentioned purpose of the present invention can be achieved by adopting the following technical solutions:

[0009] The present invention provides a gas-liquid downhole separation and injection-up production method for a gas well, which adopts an injection-down production operation system;

[0010] The injection-down and production-up operation system comprises a ground production-injection pipeline, a wellbore, and an injection-down and production-up pipe string arranged in the wellbore, and an oil casing annulus is formed between the injection-down and production-up pipe string and the wellbore;

[0011] The injection and production upper tubing string comprises a bypass check valve, a packer and a check valve connected in sequence from top to bottom, the check valve adopts a structure that can be opened downward and closed upward, the packer is used to isolate the oil casing annulus, and the bypass check valve has a one-way conduction structure from the oil casing annulus to the inner cavity of the injection and production upper tubing string;

[0012] The gas well stratum has a gas production layer and a water injection layer, the gas production layer is located above the water injection layer, and the packer is arranged between the gas production layer and the water injection layer;

[0013] The surface production and injection pipeline comprises:

[0014] A pipe string pipeline connected to the inner cavity of the injection and production pipe string;

[0015] An oil casing pipeline connected to the oil casing annulus;

[0016] Gas pipeline;

[0017] The injection-down and collection-up method comprises:

[0018] Step S10, draining the oil pressure;

[0019] Step S20, normal gas collection;

[0020] Step S30, injecting water downhole;

[0021] In the step S10, the column pipeline is connected to the gas production pipeline, and the oil casing pipeline is disconnected from the gas production pipeline;

[0022] In the step S20, the oil casing pipeline is connected to the gas production pipeline, and the pipe column pipeline is disconnected from the gas production pipeline;

[0023] In the step S30, the tubing string pipeline is connected to the oil-casing pipeline and both are disconnected from the gas production pipeline; or, the tubing string pipeline is disconnected from the oil-casing pipeline and the gas production pipeline and the tubing string pipeline is connected to an external pressure supply device; or, the tubing string pipeline is disconnected from the oil-casing pipeline and the gas production pipeline, and the oil-casing annulus is pressurized to force gas and liquid to enter the interior of the injection and production tubing string through the bypass one-way valve.

[0024] In a preferred embodiment, the surface production and injection pipeline includes a first control valve, a second control valve and a third control valve, the tubing line is connected to the first pipeline node through the first control valve, the oil casing line is connected to the first pipeline node through the second control valve, and the gas production pipeline is connected to the first pipeline node through the third control valve.

[0025] In a preferred embodiment, the first control valve and the third control valve are opened, and the second control valve is closed to implement the step S10;

[0026] The first control valve is closed, and the second control valve and the third control valve are opened to implement step S20.

[0027] In a preferred embodiment, the first control valve and the second control valve are opened to connect the tubing string with the casing pipeline to implement step S30; alternatively, the first control valve and the second control valve are closed to hold the pressure in the casing annulus to force the gas and liquid to enter the injection and production tubing string through the bypass one-way valve to implement step S30.

[0028] In a preferred embodiment, the tubing string pipeline is provided with an oil pressure gauge, and the oil casing pipeline is provided with a casing pressure gauge.

[0029] In a preferred embodiment, after the casing pressure of the casing pressure gauge is higher than the oil pressure of the oil pressure gauge, step S30 is implemented.

[0030] In a preferred embodiment, the surface production and injection pipeline includes a fourth control valve, a fifth control valve and a high-pressure gas source, and the high-pressure gas source serves as the external pressure supply device;

[0031] The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve;

[0032] The second pipeline node is connected to the high-pressure gas source through the fourth control valve.

[0033] In a preferred embodiment, the fifth control valve, the first control valve and the third control valve are opened, and the second control valve and the fourth control valve are closed to implement step S10;

[0034] The second control valve and the third control valve are opened, the first control valve and the fifth control valve are closed, and the fourth control valve is continued to be closed to implement the step S20.

[0035] In a preferred embodiment, the first control valve and the fourth control valve are opened to connect the column pipeline with the high-pressure gas source, and the fifth control valve is continued to be closed to implement step S30.

[0036] In a preferred embodiment, when the step S30 is implemented, the fifth control valve continues to be closed, and the second control valve and the third control valve remain open to perform gas extraction.

[0037] In a preferred embodiment, the surface production and injection pipeline includes a fourth control valve, a fifth control valve, a sixth control valve and a compressor, and the compressor serves as the external pressure supply device;

[0038] The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve;

[0039] The second pipeline node is connected to the outlet of the compressor through the fourth control valve;

[0040] The inlet of the compressor is connected to the first line node via the sixth control valve.

[0041] In a preferred embodiment, the first control valve, the fourth control valve, and the sixth control valve are opened, the second control valve is kept open, the fifth control valve is kept closed, and the compressor is started to implement step S30.

[0042] In a preferred embodiment, when performing step S30, the third control valve is opened.

[0043] In a preferred embodiment, the injection and production operation system includes a liquid level monitoring device, which is used to monitor the liquid level in the injection and production tubing string downhole and is installed at the top of the channel in the injection and production tubing string.

[0044] In a preferred embodiment, when the liquid level monitoring device detects that the liquid level in the injection and production upper pipe string drops to a level close to the bypass one-way valve or meets the requirements, the step S30 is stopped.

[0045] In a preferred embodiment, the injection and mining operation system includes a controller, and the controller is used to control the switching of each control valve according to the monitoring signal of the liquid level monitoring device.

[0046] In a preferred embodiment, the outlet end of the one-way valve is connected to a bell mouth.

[0047] In a preferred embodiment, the method of injecting down and mining up further comprises:

[0048] Step S40, draining the oil pressure;

[0049] Step S50, normal gas collection;

[0050] The step S10, the step S20, the step S30, the step S40 and the step S50 are implemented in sequence.

[0051] The present invention provides a gas well gas-liquid downhole separation injection and production operation system, which is applied to the above-mentioned gas well gas-liquid downhole separation injection and production method;

[0052] The injection-down and production-up operation system comprises a ground production-injection pipeline, a wellbore and an injection-down and production-up pipe string arranged in the wellbore, and an oil casing annulus is formed between the injection-down and production-up pipe string and the wellbore;

[0053] The injection and production upper tubing string comprises a bypass check valve, a packer and a check valve connected in sequence from top to bottom, the check valve adopts a structure that can be opened downward and closed upward, the packer is used to isolate the oil casing annulus, and the bypass check valve has a one-way conduction structure from the oil casing annulus to the inner cavity of the injection and production upper tubing string;

[0054] The gas well stratum has a gas production layer and a water injection layer, the gas production layer is located above the water injection layer, and the packer is arranged between the gas production layer and the water injection layer;

[0055] The surface production and injection pipeline comprises:

[0056] A pipe string pipeline connected to the inner cavity of the injection and production pipe string;

[0057] An oil casing pipeline connected to the oil casing annulus;

[0058] Gas pipeline;

[0059] The surface production and injection pipeline includes a first control valve, a second control valve and a third control valve. The tubing string pipeline is connected to the first pipeline node through the first control valve, the oil casing pipeline is connected to the first pipeline node through the second control valve, and the gas production pipeline is connected to the first pipeline node through the third control valve.

[0060] The present invention provides a gas well gas-liquid downhole separation injection and production system, which is applied to the above-mentioned gas well gas-liquid downhole separation injection and production method;

[0061] The injection-down and production-up system comprises a surface production-injection pipeline and an injection-down and production-up pipe string, wherein the injection-down and production-up pipe string is used to be arranged in a wellbore and to form an oil casing annulus between the wellbore and the wellbore;

[0062] The injection and production upper tubing string comprises a bypass check valve, a packer and a check valve connected in sequence from top to bottom, the check valve adopts a structure that can be opened downward and closed upward, the packer is used to isolate the oil casing annulus, and the bypass check valve has a one-way conduction structure from the oil casing annulus to the inner cavity of the injection and production upper tubing string;

[0063] The packer is used to be arranged in the wellbore and is located between the upper gas production layer and the lower water injection layer;

[0064] The surface production and injection pipeline comprises:

[0065] A pipe string pipeline connected to the inner cavity of the injection and production pipe string;

[0066] An oil casing pipeline connected to the oil casing annulus;

[0067] Gas pipeline;

[0068] The surface production and injection pipeline includes a first control valve, a second control valve and a third control valve. The tubing string pipeline is connected to a first pipeline node through the first control valve, the oil casing pipeline is connected to the first pipeline node through the second control valve, and the gas production pipeline is connected to the first pipeline node through the third control valve.

[0069] In a preferred embodiment, the injection-down and production-up system comprises a liquid level monitoring device, and the liquid level monitoring device is installed on the top of the channel in the injection-down and production-up pipe string.

[0070] In a preferred embodiment, the tubing string pipeline is connected to an oil pressure gauge, and the oil casing pipeline is connected to a casing pressure gauge.

[0071] In a preferred embodiment, the injection and production system includes a controller, which is used to control the switching of each control valve according to the monitoring signal of the liquid level monitoring device, the detection signal of the oil pressure gauge and the detection signal of the casing pressure gauge.

[0072] In a preferred embodiment, the one-way valve adopts a sliding sleeve ball throwing structure, which can shear the sliding sleeve shear pins of the one-way valve by throwing a ball.

[0073] In a preferred embodiment, the one-way valve adopts a structure in which the valve core and the valve body are separated, the valve body is directly connected to the oil pipe coupling of the injection and production pipe string, and the valve core can be repeatedly cast in and out.

[0074] In a preferred embodiment, the packer has a slip anchoring function, and the packer is connected to the oil pipe of the injection and production string by inserting the pipe back.

[0075] In a preferred embodiment, the injection and production upper pipe string includes an oil pipe or a drill pipe or a small casing.

[0076] In a preferred embodiment, the power supply for the injection-production system comes from large-scale electricity at the well site, a generator, or wind power and solar power at the well site.

[0077] In a preferred embodiment, the surface production and injection pipeline includes a fourth control valve, a fifth control valve and a high-pressure gas source, and the high-pressure gas source serves as the external pressure supply device;

[0078] The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve;

[0079] The second pipeline node is connected to the high-pressure gas source through the fourth control valve.

[0080] In a preferred embodiment, the surface production and injection pipeline includes a fourth control valve, a fifth control valve, a sixth control valve and a compressor, and the compressor serves as the external pressure supply device;

[0081] The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve;

[0082] The second pipeline node is connected to the outlet of the compressor through the fourth control valve;

[0083] The inlet of the compressor is connected to the first line node via the sixth control valve.

[0084] The characteristics and advantages of the present invention are:

[0085] The present invention provides a method for downhole gas-liquid separation and injection and production in a gas well. In step S10, oil pressure is vented through the gas production pipeline to reduce the oil pressure in the injection and production string, so that the liquid from the gas production layer in the downhole oil casing annulus enters the injection and production string through the bypass one-way valve, thereby raising the liquid level in the injection and production string; when the oil pressure is reduced to the limit of the gas production pipeline, step S20 is implemented to perform normal gas production.

[0086] When the liquid level in the downhole injection and production upper tubing string is high, step S30 is implemented to allow the high-pressure oil casing annular gas or the high-pressure gas provided by the external pressure supply device to push the liquid in the tubing string through the one-way valve and inject it back into the water injection layer, thereby lowering the liquid level in the downhole injection and production upper tubing string.

[0087] This method of injection-down and production-up adopts rodless water injection and annular gas production to carry out gas well drainage and gas production, which is particularly suitable for liquid-accumulated wells and large-water-gas wells. It avoids the surface treatment of produced fluid, realizes direct underground reinjection of produced fluid without reaching the ground, lowers the wellbore liquid level, and achieves the purpose of annular gas production. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0089] Figure 1 A schematic diagram of an embodiment of a gas-liquid downhole separation and injection-down and production-up operation system for a gas well provided by the present invention;

[0090] Figure 2 A schematic diagram of another embodiment of the gas-liquid downhole separation and injection-down and production-up operation system for a gas well provided by the present invention;

[0091] Figure 3 A schematic diagram of another embodiment of the gas-liquid downhole separation and injection-down and production-up operation system for a gas well provided by the present invention;

[0092] Figure 4 A schematic diagram of the gas-liquid downhole separation and injection-upstream production method for a gas well provided by the present invention.

[0093] Description of Figure Numbers:

[0094] 1. Oil pipe;

[0095] 2. Bypass check valve; 3. Packer; 4. Check valve; 5. Bell mouth;

[0096] 6. Liquid level monitoring device;

[0097] 7. The first control valve;

[0098] 8. Oil pressure gauge; 9. Controller; 10. Casing pressure gauge;

[0099] 11. Second control valve; 12. Third control valve;

[0100] 13. Fourth control valve; 15. Fifth control valve;

[0101] 17. Sixth control valve;

[0102] 14. High-pressure gas source; 16. Compressor;

[0103] 21. First pipeline node; 22. Second pipeline node;

[0104] 23. Pipeline; 24. Oil casing pipeline; 25. Gas production pipeline;

[0105] 31. Valve No. 1; 32. Valve No. 2; 33. Valve No. 3; 34. Valve No. 4; 35. Valve No. 5; 36. Valve No. 6; 37. Valve No. 7; 38. Valve No. 8; 39. Valve No. 9.

[0106] 40. Wellbore; 41. Surface casing; 42. Gas casing; 43. Oil casing annulus; 44. Injection and production tubing string;

[0107] 50. Water and liquid; 51. Gas production layer; 52. Water injection layer. DETAILED DESCRIPTION

[0108] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0109] Solution 1

[0110] The present invention provides a method for gas-liquid downhole separation and injection and production in a gas well, which adopts an injection and production operation system;

[0111] like Figure 1-Figure 3 As shown, the injection-down and production-up operation system includes a surface production-injection pipeline, a wellbore 40, and an injection-down and production-up pipe string 44 disposed in the wellbore 40, and an oil casing annulus 43 is formed between the injection-down and production-up pipe string 44 and the wellbore 40;

[0112] The injection and production upper pipe string 44 includes a bypass check valve 2, a packer 3 and a check valve 4 connected in sequence from top to bottom. The check valve 4 adopts a structure that can be opened downward and closed upward. The packer 3 is used to isolate the oil casing annulus 43. The bypass check valve 2 has a one-way conduction structure from the oil casing annulus 43 to the inner cavity of the injection and production upper pipe string 44.

[0113] The gas well stratum has a gas production layer 51 and a water injection layer 52, the gas production layer 51 is located above the water injection layer 52, and the packer 3 is arranged between the gas production layer 51 and the water injection layer 52;

[0114] The surface production and injection pipeline includes:

[0115] A pipe string line 23 connected to the inner cavity of the injection and production pipe string 44;

[0116] The oil casing pipeline 24 connected to the oil casing annulus 43;

[0117] Gas production pipeline 25;

[0118] like Figure 4 As shown, the injection-down and collection-up methods include:

[0119] Step S10, draining the oil pressure;

[0120] Step S20, normal gas collection;

[0121] Step S30, injecting water downhole;

[0122] In step S10, the column pipeline 23 is connected to the gas production pipeline 25, and the oil casing pipeline 24 is disconnected from the gas production pipeline 25;

[0123] In step S20, the oil casing pipeline 24 is connected to the gas production pipeline 25, and the column pipeline 23 is disconnected from the gas production pipeline 25;

[0124] In step S30, the tubing string pipeline 23 is connected to the oil casing pipeline 24 and both are disconnected from the gas production pipeline 25; or, the tubing string pipeline 23 is disconnected from the oil casing pipeline 24 and the gas production pipeline 25 and the tubing string pipeline 23 is connected to an external pressure supply device; or, the tubing string pipeline 23 is disconnected from the oil casing pipeline 24 and the gas production pipeline 25, and the oil casing annulus 43 is pressurized to force the gas and liquid to pass through the bypass one-way valve 2 into the lower injection and upper production tubing string 44.

[0125] The present invention provides a method for downhole gas-liquid separation and injection and production in a gas well. In step S10, oil pressure is vented through the gas production pipeline 25 to reduce the oil pressure in the injection and production string 44, so that the liquid from the gas production layer 51 in the downhole casing annulus 43 enters the injection and production string 44 through the bypass one-way valve 2, thereby raising the liquid level in the injection and production string 44. When the oil pressure drops to the limit of the gas production pipeline 25, step S20 is implemented to perform normal gas production.

[0126] When the liquid level in the downhole injection and production upper tubing string 44 is high, step S30 is implemented to allow the high-pressure oil casing annulus 43 gas or the high-pressure gas provided by the external pressure supply device to push the liquid in the tubing string through the one-way valve 4 to be injected back into the water injection layer 52, or to hold the pressure to lower the liquid level in the downhole injection and production upper tubing string 44.

[0127] This method of injection-down and production-up adopts rodless water injection and annular gas production to carry out gas well drainage and gas production, which is particularly suitable for liquid-accumulated wells and large-water-gas wells. It avoids the surface treatment of produced fluid, realizes direct underground reinjection of produced fluid without reaching the ground, lowers the wellbore liquid level, and achieves the purpose of annular gas production.

[0128] The wellbore 40 may be formed by casing or an uncemented open hole wall. Specifically, the casing may include a surface casing 41 and a gas casing 42, or one of them. The injection and production pipe string 44 includes an oil pipe 1 or a drill pipe or a small casing; the surface production and injection pipeline serves as a surface supporting system. Furthermore, the outlet end of the one-way valve 4 is connected to a bell mouth 5, such as Figure 1 As shown, the lower end of the oil pipe 1 is connected with a bell mouth 5, and the oil pipe 1 above the bell mouth 5 is connected with a one-way valve 4, a packer 3, and a bypass one-way valve 2 in sequence; the one-way valve 4 adopts a structure that can be opened downward and closed upward, so that the liquid can only flow downward in one direction; after the packer 3 is sealed, the oil casing annulus 43 can be sealed; the bypass one-way valve 2 is similar to a gas lift valve, and has a one-way conduction structure from the oil casing annulus 43 to the oil pipe 1, and the water and liquid 50 in the oil casing annulus 43 can enter the inner cavity of the tubing string through the bypass one-way valve 2.

[0129] In one embodiment, the injection-down and production-up method further includes: step S40, oil pressure venting; step S50, normal gas production; step S10, step S20, step S30, step S40 and step S50 are performed in sequence, and the gas well resumes normal gas production after the water is drained. The specific operation of oil pressure venting in step S40 can be substantially the same as step S10; the specific operation of normal gas production in step S50 can be substantially the same as step S20.

[0130] In one embodiment, the surface production and injection pipeline includes a first control valve 7, a second control valve 11 and a third control valve 12. Figure 1 As shown, the tubing string pipeline 23 is connected to the first pipeline node 21 through the first control valve 7, the oil casing pipeline 24 is connected to the first pipeline node 21 through the second control valve 11, and the gas production pipeline 25 is connected to the first pipeline node 21 through the third control valve 12. The first control valve 7, the second control valve 11 and the third control valve 12 are used to control the connection and disconnection between the pipelines, so as to implement the operations of oil pressure venting, gas production and downhole water injection in steps.

[0131] Figure 1 In the injection-down and production-up operation system shown, the first control valve 7 and the third control valve 12 are opened, and the second control valve 11 is closed to implement step S10; the first control valve 7 is closed, and the second control valve 11 and the third control valve 12 are opened to implement step S20 to ensure reliable control and stable progress of oil pressure venting and normal gas production.

[0132] Further, the first control valve 7 and the second control valve 11 are opened to connect the tubing string pipeline 23 with the casing pipeline 24 to implement step S30, so that the high-pressure gas in the casing annulus 43 pushes the liquid in the tubing to pass through the one-way valve 4 and inject back into the water injection layer 52, and the liquid level in the tubing drops.

[0133] In another embodiment, the first control valve 7 and the second control valve 11 are closed to hold the pressure in the casing annulus 43, forcing the gas and liquid to pass through the bypass one-way valve 2 and enter the injection and production tubing string 44, so as to implement step S30.

[0134] In one embodiment, the tubing string pipeline 23 is provided with an oil pressure gauge 8 , and the oil casing pipeline 24 is provided with a casing pressure gauge 10 . The oil pressure of the oil pipe is detected by the oil pressure gauge 8 , and the casing pressure of the oil casing annulus 43 is detected by the casing pressure gauge 10 . Figure 1 In the injection-down and production-up operation system shown, after the casing pressure of the casing pressure gauge 10 is higher than the oil pressure of the oil pressure gauge 8 , step S30 is implemented to utilize the higher-pressure gas in the casing annulus 43 to push the liquid in the oil pipe to be injected back into the water injection layer 52 .

[0135] Before implementing step S30, the oil pressure of the oil pipe and the casing pressure of the casing annulus 43 are detected by the oil pressure gauge 8 and the casing pressure gauge 10. If the casing pressure does not meet the requirement of injecting water into the water injection layer 52 through the oil pipe, the second control valve 11 can be closed to hold the pressure for a period of time, and the gas from the gas production layer 51 continuously enters the casing annulus 43 to increase the casing pressure until the water injection requirement is met.

[0136] In one embodiment, the surface production and injection pipeline further includes a fourth control valve 13, a fifth control valve 15 and a high-pressure gas source 14, and the high-pressure gas source 14 serves as an external pressure supply device; Figure 2 As shown, the column pipeline 23 is connected to the second pipeline node 22 through the first control valve 7, and the second pipeline node 22 is connected to the first pipeline node 21 through the fifth control valve 15; the second pipeline node 22 is connected to the high-pressure gas source 14 through the fourth control valve 13. The first control valve 7, the second control valve 11, the third control valve 12, the fourth control valve 13 and the fifth control valve 15 are used to control the connection and disconnection between the pipelines, so as to implement the oil pressure venting, gas production and downhole water injection in steps; and the oil pipe gas injection comes from the high-pressure gas source 14, which can be other gas wells, gas transmission pipelines, nitrogen generators or gas storage tanks, and does not have to rely on the gas in the oil casing annulus 43.

[0137] Figure 2 In the injection-down and production-up operation system shown, the fifth control valve 15, the first control valve 7 and the third control valve 12 are opened, and the second control valve 11 and the fourth control valve 13 are closed to implement step S10; the second control valve 11 and the third control valve 12 are opened, the first control valve 7 and the fifth control valve 15 are closed, and the fourth control valve 13 continues to be closed to implement step S20, thereby ensuring reliable control and stable progress of oil pressure venting and normal gas production.

[0138] Further, the first control valve 7 and the fourth control valve 13 are opened to connect the pipe column pipeline 23 with the high-pressure gas source 14, and the fifth control valve 15 is continued to be closed to implement step S30, and the high-pressure gas from the high-pressure gas source 14 is used to push the liquid in the oil pipe back into the water injection layer 52, so as to achieve the purpose of lowering the liquid level in the oil pipe. Preferably, when implementing step S30, the fifth control valve 15 is continued to be closed, and the second control valve 11 and the third control valve 12 are kept open to carry out gas production, so as to realize gas production while injecting water.

[0139] In one embodiment, the surface production and injection pipeline further includes a fourth control valve 13, a fifth control valve 15, a sixth control valve 17 and a compressor 16, and the compressor 16 serves as an external pressure supply device; Figure 3 As shown, the column pipeline 23 is connected to the second pipeline node 22 through the first control valve 7, and the second pipeline node 22 is connected to the first pipeline node 21 through the fifth control valve 15; the second pipeline node 22 is connected to the outlet of the compressor 16 through the fourth control valve 13; the inlet of the compressor 16 is connected to the first pipeline node 21 through the sixth control valve 17. The first control valve 7, the second control valve 11, the third control valve 12, the fourth control valve 13, the fifth control valve 15 and the sixth control valve 17 are used to control the connection and disconnection between the pipelines, so as to implement the oil pressure venting, gas production and downhole water injection operations in steps; the oil pipe gas injection comes from the casing annulus 43 of the well, and is pressurized by the compressor 16. When the casing pressure of the casing annulus 43 of the well is not enough, the second control valve 11 can be closed to hold the pressure, so that the gas well can increase the casing pressure by itself, and the gas in the casing annulus 43 of the well can be fully utilized, which is conducive to saving resources; the third control valve 12 can be opened to directly use the gas in the gas production pipeline 25 or the casing annulus 43 of the well.

[0140] Figure 3 In the injection-down and mining-up operation system shown in FIG. Figure 2 The following notes are shown to be implemented using the above operating system. Figure 3 In the injection-down and production-up operation system shown, the first control valve 7, the fourth control valve 13, and the sixth control valve 17 are opened, the second control valve 11 is kept open, the fifth control valve 15 is kept closed, and the compressor 16 is started to implement step S30 to pressurize the gas from the casing annulus 43 of the well or the gas from the gas production pipeline 25, so as to push the tubing fluid back into the water injection layer 52, thereby achieving the purpose of lowering the tubing fluid level.

[0141] In one embodiment, when step S30 is implemented, the third control valve 12 is opened, and while producing gas, a portion of the gas from the casing annulus 43 of the well is pressurized and used to push the tubing fluid back into the water injection layer 52 .

[0142] In one embodiment, the injection and production operation system includes a liquid level monitoring device 6, which is used to monitor the liquid level height in the injection and production tubing string 44 underground, so as to control the start or stop of underground water injection according to the liquid level height in the injection and production tubing string 44.

[0143] Furthermore, when the liquid level monitoring device 6 detects that the liquid level in the injection and production string 44 drops to close to the bypass check valve 2 or meets the requirements, step S30 is stopped. Specifically, it can be set in advance: when the distance between the liquid level in the string and the bypass check valve 2 reaches a preset distance, it is considered to be close to the bypass check valve 2; or when the liquid level in the string reaches a first preset height, it is considered to meet the requirements. When the liquid level in the string rises to a second preset height and other conditions are met, downhole water injection begins.

[0144] In one embodiment, the injection-down and production-up operation system includes a controller 9, which is used to control the switches of various control valves according to the monitoring signal of the liquid level monitoring device 6, the detection signal of the oil pressure gauge 8 and the detection signal of the casing pressure gauge 10. The first control valve 7, the second control valve 11, the third control valve 12, the fourth control valve 13, the fifth control valve 15 and the sixth control valve 17 can all be automatic control valves, the liquid level monitoring device 6 can be an automatic liquid level monitoring device, and is electrically connected to the controller 9 respectively. The controller 9 controls the switches of various control valves according to the injection-down and production-up method described above, so as to realize automatic steps such as oil pressure venting, gas production and downhole water injection.

[0145] This method of injecting down and producing up adopts liquid level monitoring, rodless water injection, and annular gas production to solve the problem of gas well drainage and gas production, avoids the ground treatment of produced fluid, realizes direct underground reinjection of produced fluid without reaching the ground, lowers the liquid level in the wellbore, and achieves the purpose of annular gas production. It is especially suitable for liquid-accumulated wells and large water and gas wells.

[0146] The method of injecting down and collecting up may also include the following steps:

[0147] Step 1: Wellbore preparation:

[0148] Identify the gas well. If the gas well is an old well, it is necessary to pull out the original well string. Pull out the original well string and clean the well and scrape the casing as needed. If the gas well is a new well, it is also necessary to pull out the original well string if there is an original well string and clean the well as needed.

[0149] Then, select the water injection layer 52 at the bottom of the gas well to ensure that there is a good barrier between the water injection layer 52 and the gas production layer 51 to avoid leakage interference between layers. If there is no ready-made water injection layer 52, perforation, injection or cutting can be used to make a patch hole on a dry layer below the gas production layer 51 as the water injection layer 52, and the water injection test must be qualified.

[0150] Step 2: lower the injection and production upper pipe string 44:

[0151] The upper injection and production tubing string 44 is lowered to seat the packer 3 between the water injection layer 52 and the gas production layer 51 , and close to the water injection layer 52 , so that the bypass check valve 2 is located between the gas production layer 51 and the packer 3 .

[0152] Step 3: Install the ground supporting system:

[0153] After the gas wellhead is installed, the matching installation can be carried out according to the actual situation of the gas source on site. Figure 1-Figure 3 One of three ground support systems shown.

[0154] Step 4: Debug and run:

[0155] First, open the oil pipe passage and the oil casing annulus 43 passage valve of the gas production well head itself on the oil pressure gauge 8 and the casing pressure gauge 10 side.

[0156] (1) Targeting Figure 1 In the ground supporting system shown, the controller 9 is set to:

[0157] Implementation step S10: first close the second control valve 11, open the first control valve 7 and the third control valve 12, and drain the oil pressure through the gas production pipeline 25 to reduce the oil pressure of the oil pressure gauge 8, so as to promote the liquid from the gas production layer 51 in the downhole casing annulus 43 to enter the oil pipe through the bypass check valve 2, thereby raising the liquid level in the oil pipe 1;

[0158] Implementation step S20: When the oil pressure drops to the limit of the gas production pipeline 25, close the first control valve 7, open the second control valve 11, and ensure that the third control valve 12 is continuously opened, so as to perform normal gas production.

[0159] Implementation step S30: When the liquid level monitoring device 6 detects that the liquid level in the downhole oil pipe 1 is relatively high and the casing pressure of the casing pressure gauge 10 is higher than the oil pressure of the oil pressure gauge 8, and the requirement of injecting water from the oil pipe 1 into the water injection layer 52 is met, the third control valve 12 is closed, the first control valve 7 is opened, and the second control valve 11 is ensured to be continuously opened, so that the higher-pressure gas in the casing annulus 43 pushes the liquid in the oil pipe 1 through the one-way valve 4 and is injected back into the water injection layer 52, and the liquid level in the oil pipe drops.

[0160] When the liquid level monitoring device 6 detects that the liquid level in the oil pipe 1 drops above the bypass check valve 2 or meets the requirements, the third control valve 12 is opened, the second control valve 11 is closed, the oil pressure is vented through the gas production pipeline 25, and then normal gas production is carried out.

[0161] If the casing pressure does not meet the requirement of injecting water into the water injection layer 52 through the oil pipe 1, the second control valve 11 is closed to hold the pressure for a period of time, and the gas from the gas production layer 51 continuously enters the oil casing annulus 43 to increase the casing pressure until the water injection requirement is met. Then the controller 9 is started to test and ensure normal operation.

[0162] (2) Targeting Figure 2 In the ground supporting system shown, the controller 9 is set to:

[0163] Implementation step S10: First, close the second control valve 11 and the fourth control valve 13, open the first control valve 7, the third control valve 12, and the fifth control valve 15, and vent the oil pressure through the gas production pipeline 25 to reduce the oil pressure of the oil pressure gauge 8, so as to cause the liquid from the gas production layer 51 in the downhole casing annulus 43 to enter the oil pipe through the bypass one-way valve 2, thereby raising the liquid level in the oil pipe 1.

[0164] Implementation step S20: When the oil pressure drops to the limit of the gas production pipeline 25, close the first control valve 7 and the fifth control valve 15, continue to close the fourth control valve 13, open the second control valve 11, continue to open the third control valve 12, and perform normal gas production.

[0165] Implementation step S30: When the liquid level monitoring device 6 detects that the liquid level in the downhole oil pipe 1 is high, the first control valve 7 and the fourth control valve 13 are opened, the fifth control valve 15 continues to be closed, and the second control valve 11 and the third control valve 12 continue to be opened for normal gas production, so that the high-pressure gas from the high-pressure gas source 14 pushes the liquid in the oil pipe 1 through the one-way valve 4 and is injected back into the water injection layer 52, thereby achieving the purpose of lowering the liquid level in the oil pipe 1.

[0166] When the liquid level monitoring device 6 detects that the liquid level in the oil pipe 1 drops to above the bypass check valve 2 or meets the requirements, the second control valve 11 and the fourth control valve 13 are closed, the fifth control valve 15 is opened, and the third control valve 12 is opened to vent the oil pressure, and then normal gas collection is carried out according to the method of the above steps S10 and S20. Then the controller 9 is started, tested, and normal operation is ensured.

[0167] (3) Targeting Figure 3 In the ground supporting system shown, the controller 9 is set to:

[0168] In the implementation steps S10 and S20, the sixth control valve 17 is kept closed, and the other steps are as follows. Figure 2 The operation method of the ground supporting system is shown.

[0169] Implementation step S30: When the liquid level monitoring device 6 detects that the liquid level in the downhole oil pipe 1 is high, the first control valve 7, the third control valve 12, the fourth control valve 13, and the sixth control valve 17 are opened, the fifth control valve 15 continues to be closed, and the second control valve 11 continues to be opened, and then the compressor 16 is started to pressurize the gas from the well casing annulus 43 or the gas production pipeline 25, so as to push the liquid in the oil pipe 1 back into the water injection layer 52 through the one-way valve 4, so as to achieve the purpose of lowering the liquid level in the oil pipe 1.

[0170] When the liquid level monitoring device 6 detects that the liquid level in the oil pipe 1 drops to above the bypass check valve 2 or meets the requirements, the compressor 16, the second control valve 11, the fourth control valve 13, and the sixth control valve 17 are closed, the fifth control valve 15 is opened, and the first control valve 7 and the third control valve 12 are opened to vent the oil pressure, and then normal gas collection is carried out according to the method of the above steps S10 and S20. Then the controller 9 is started, tested, and normal operation is ensured.

[0171] Solution 2

[0172] The present invention provides a gas well gas-liquid downhole separation injection and production operation system, which is applied to the above-mentioned gas well gas-liquid downhole separation injection and production method; Figure 1-Figure 3 As shown, the injection-down and production-up operation system includes a surface production-injection pipeline, a wellbore 40, and an injection-down and production-up pipe string 44 disposed in the wellbore 40, and an oil casing annulus 43 is formed between the injection-down and production-up pipe string 44 and the wellbore 40;

[0173] The injection and production upper pipe string 44 includes a bypass check valve 2, a packer 3 and a check valve 4 connected in sequence from top to bottom. The check valve 4 adopts a structure that can be opened downward and closed upward. The packer 3 is used to isolate the oil casing annulus 43. The bypass check valve 2 has a one-way conduction structure from the oil casing annulus 43 to the inner cavity of the injection and production upper pipe string 44.

[0174] The gas well stratum has a gas production layer 51 and a water injection layer 52, the gas production layer 51 is located above the water injection layer 52, and the packer 3 is arranged between the gas production layer 51 and the water injection layer 52;

[0175] The surface production and injection pipeline includes:

[0176] A pipe string line 23 connected to the inner cavity of the injection and production pipe string 44;

[0177] The oil casing pipeline 24 connected to the oil casing annulus 43;

[0178] Gas production pipeline 25;

[0179] The surface production and injection pipeline includes a first control valve 7, a second control valve 11 and a third control valve 12. The tubing line 23 is connected to the first pipeline node 21 through the first control valve 7, the oil casing pipeline 24 is connected to the first pipeline node 21 through the second control valve 11, and the gas production pipeline 25 is connected to the first pipeline node 21 through the third control valve 12.

[0180] The injection-down and production-up operation system is used to separate gas and liquid in the gas well, and the injection-down and production-up operation is carried out. The rodless water injection and annular gas production methods are used to drain water and produce gas in the gas well, avoiding the surface treatment of the produced liquid, and achieving direct underground reinjection of the produced liquid before it reaches the ground, thereby lowering the liquid level in the wellbore and achieving the purpose of annular gas production. It is suitable for liquid-accumulated wells and large water and gas wells.

[0181] The bypass check valve 2 and the check valve 4 are also preferably arranged between the gas production layer 51 and the water injection layer 52. Figure 1 As shown, the surface production and injection pipeline may also be provided with valve No. 1 31, valve No. 2 32, valve No. 33, valve No. 4 34, valve No. 5 35, valve No. 6 36, valve No. 7 37, valve No. 8 38 and valve No. 9 39. Preferably, the liquid level monitoring device 6 is installed at the top of the channel in the injection and production pipe string at the gas production wellhead, and installed on the top of valve No. 7 37.

[0182] Furthermore, the one-way valve 4 can adopt a sliding sleeve ball-throwing structure. When necessary, the sliding sleeve shear nails of the one-way valve 4 can be cut off by throwing a ball, and the one-way valve 4 can fall into the bottom of the artificial well to achieve unobstructed communication up and down. The one-way valve 4 can adopt a structure in which the valve core and the valve body are separated. The valve body is similar to a working cylinder and is directly connected to the coupling of the oil pipe 1. The valve core can be repeatedly thrown and fished out, which is convenient for the maintenance of the one-way valve 4. According to the actual situation, the valve core can be fished out by wire operation, so that the one-way valve 4 loses its one-way function, which is convenient for the acidification, unblocking and water injection of the injection layer 52.

[0183] Furthermore, the packer 3 has a slip anchoring function to prevent the pipe string from moving up and down. The packer 3 can be connected to the upper oil pipe 1 by inserting the pipe back to avoid directly pulling out the packer 3 during subsequent well repair and pulling out the pipe string, resulting in overflow of the previous injection water.

[0184] In one embodiment, if Figure 1 As shown, the gas injection in the oil pipe 1 comes from the high-pressure gas in the casing annulus 43 of the well. The ground supporting system is equipped with a controller 9, a first control valve 7, a second control valve 11, a third control valve 12, an oil pressure gauge 8 and a casing pressure gauge 10; the first control valve 7 and the second control valve 11 are connected in series between the side outlet of the oil pipe 1 at the gas production wellhead and the side outlet of the casing annulus 43 through pipelines, and can be connected in series between the No. 9 valve 39 and the No. 6 valve 36 at the gas production wellhead; on the same side of the first control valve 7 and the second control valve 11 ( Figure 1The third control valve 12 is also connected between the pipelines that converge to the gas production pipeline 25. The oil pressure gauge 8 is connected to the pipeline between the side outlet of the gas production wellhead oil pipe 1 and the first control valve 7, specifically, the pipeline between the No. 9 valve 39 and the first control valve 7; the casing pressure gauge 10 is connected to the pipeline between the side outlet of the oil casing annulus 43 at the gas production wellhead and the second control valve 11, specifically, the pipeline between the No. 6 valve 36 and the second control valve 11; the first control valve 7 and the second control valve 11 are connected in series between the No. 9 valve 39 and the No. 6 valve 36 through pipelines, the left side of the third control valve 12 is connected to the pipeline between the first control valve 7 and the second control valve 11, and the right side is connected to the gas production pipeline 25, the oil pressure gauge 8 is connected to the pipeline between the No. 9 valve 39 and the first control valve 7, and the casing pressure gauge 10 is connected to the pipeline between the No. 6 valve 36 and the second control valve 11.

[0185] The controller 9 can be connected to the first control valve 7, the second control valve 11, the third control valve 12, the oil pressure gauge 8, the casing pressure gauge 10, and the liquid level monitoring device 6 in a wireless or wired manner. The controller 9 can be installed at any position, preferably on the upper part of the third control valve 12, close to the ground, for easy debugging by personnel; the ground supporting system power supply can come from the well site power supply, generator or well site wind power and solar power supply. In actual use, this embodiment is suitable for gas wells with sufficient formation pressure and large oil-casing pressure difference.

[0186] In another embodiment, if Figure 2 As shown, the oil pipe 1 is injected with gas from a high pressure gas source 14. Figure 1 Compared with the embodiment shown in the figure, the difference of this embodiment is that: the fourth control valve 13 and the fifth control valve 15 need to be connected, wherein the fifth control valve 15 is connected to the pipeline between the first control valve 7 and the second control valve 11, and is also located on the pipeline between the first control valve 7 and the third control valve 12; the right side of the fourth control valve 13 is connected to the high-pressure gas source 14 through a pipeline, and the left side is connected to the first control valve 7 and the fifth control valve 15, specifically located on the pipeline between the high-pressure gas source 14 and the first control valve 7, and is also located on the pipeline between the high-pressure gas source 14 and the fifth control valve 15, such as Figure 2 As shown, it is specifically located on the left side of the high-pressure gas source 14 and on the right side of the first control valve 7 and the fifth control valve 15. The high-pressure gas source 14 can use a compressor 16 or a pump to pressurize the gas from other gas wells, gas pipelines, or gas tanks to meet the water injection requirements of the oil pipe 1.

[0187] The controller 9 can be connected to the first control valve 7 , the second control valve 11 , the third control valve 12 , the fourth control valve 13 , the fifth control valve 15 , the oil pressure gauge 8 , the casing pressure gauge 10 and the liquid level monitoring device 6 in a wireless or wired manner.

[0188] In another embodiment, if Figure 3 As shown, the ground supporting system is suitable for the gas that needs to be pressurized in the casing annulus 43 of the well. The gas injected into the oil pipe 1 comes from the gas that needs to be pressurized in the casing annulus 43 of the well. Figure 2 On the basis of the ground supporting system in the shown embodiment, the high-pressure gas source 14 is replaced by a compressor 16, and the other end of the compressor 16 is connected to the sixth control valve 17 and the gas production pipeline 25 between the second control valve 11 and the third control valve 12 in sequence through a pipeline to pressurize the gas produced from the casing annulus 43 of the well.

[0189] The injection and production operation system provided by the present invention is divided into two major parts: an injection and production pipe string 44 underground and a ground supporting system. The whole system uses gas as a medium, and adopts the methods of automatic liquid level monitoring, rodless water injection, and annular gas production to achieve safe and effective water injection and gas production in the same well, solve the problem of gas well drainage and gas production, and solve the gas production problem of liquid accumulation wells and water-rich areas. It is especially suitable for liquid accumulation wells and large water-rich gas wells, and can effectively avoid the ground treatment of produced liquid, and realize the direct underground separation and re-injection of produced liquid before it reaches the ground, reduce the liquid level of the wellbore, and achieve the purpose of annular gas production. Among them: the injection and production pipe string 44 has a simple structure and a very low failure rate; the ground supporting system can be adjusted in real time according to the on-site well conditions, and can achieve an unmanned effect through automation and intelligence, and the operating cost is low; it is suitable for vertical wells, directional wells, and horizontal wells, and meets the needs of gas-liquid underground separation and water injection and gas production in the whole cycle of gas wells from production to the late production period.

[0190] Option 3

[0191] The present invention provides a gas well gas-liquid downhole separation injection and production system, which is applied to the above-mentioned gas well gas-liquid downhole separation injection and production method;

[0192] The injection-down and production-up system comprises a surface production-injection pipeline and an injection-down and production-up pipe string 44. The injection-down and production-up pipe string 44 is used to be arranged in a wellbore 40 and to form an oil casing annulus 43 between the wellbore 40.

[0193] The injection and production upper pipe string 44 includes a bypass check valve 2, a packer 3 and a check valve 4 connected in sequence from top to bottom. The check valve 4 adopts a structure that can be opened downward and closed upward. The packer 3 is used to isolate the oil casing annulus 43. The bypass check valve 2 has a one-way conduction structure from the oil casing annulus 43 to the inner cavity of the injection and production upper pipe string 44.

[0194] The packer 3 is used to be arranged in the wellbore 40 and is located between the upper gas production layer 51 and the lower water injection layer 52;

[0195] The surface production and injection pipeline includes:

[0196] A pipe string line 23 connected to the inner cavity of the injection and production pipe string 44;

[0197] The oil casing pipeline 24 connected to the oil casing annulus 43;

[0198] Gas production pipeline 25;

[0199] The surface production and injection pipeline includes a first control valve 7, a second control valve 11 and a third control valve 12. The tubing line 23 is connected to the first pipeline node 21 through the first control valve 7, the oil casing pipeline 24 is connected to the first pipeline node 21 through the second control valve 11, and the gas production pipeline 25 is connected to the first pipeline node 21 through the third control valve 12.

[0200] The injection and production system can be compatible with the original structure of the wellbore 40 of the gas production well to form an injection and production operation system to implement downhole gas-liquid separation and injection and production in the gas well, and to drain the gas well to produce gas, thereby avoiding surface treatment of the produced liquid, achieving direct downhole reinjection of the produced liquid without reaching the ground, lowering the liquid level in the wellbore 40, and achieving the purpose of annular gas production. It is suitable for liquid-accumulated wells and large-water-gas wells.

[0201] like Figure 1-Figure 3 As shown, the gas well gas-liquid downhole separation injection and production system may include a liquid level monitoring device 6, a controller 9, a one-way valve 4, a packer 3 and various control valves, etc. The liquid level monitoring device 6, the controller 9, the one-way valve 4, the packer 3 and various control valves, etc. have been described above and will not be repeated here. The gas well gas-liquid downhole separation injection and production system provided by the present invention has all or at least part of the technical features and effects of the above-mentioned operating system except the wellbore, which will not be repeated here.

[0202] The above are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A method for downhole separation of gas and liquid in a gas well and injection and production. It is characterized in that Adopt the injection-down and mining-up operation system; The injection-down and production-up operation system comprises a ground production-injection pipeline, a wellbore and an injection-down and production-up pipe string arranged in the wellbore, and an oil casing annulus is formed between the injection-down and production-up pipe string and the wellbore; The injection and production upper tubing string comprises a bypass check valve, a packer and a check valve connected in sequence from top to bottom, the check valve adopts a structure that can be opened downward and closed upward, the packer is used to isolate the oil casing annulus, and the bypass check valve has a one-way conduction structure from the oil casing annulus to the inner cavity of the injection and production upper tubing string; The gas well stratum has a gas production layer and a water injection layer, the gas production layer is located above the water injection layer, and the packer is arranged between the gas production layer and the water injection layer; The surface production and injection pipeline comprises: A pipe string pipeline connected to the inner cavity of the injection and production pipe string; An oil casing pipeline connected to the oil casing annulus; Gas pipeline; The injection-down and collection-up method comprises: Step S10, draining the oil pressure; Step S20, normal gas collection; Step S30, injecting water downhole; In the step S10, the column pipeline is connected to the gas production pipeline, and the oil casing pipeline is disconnected from the gas production pipeline; In the step S20, the oil casing pipeline is connected to the gas production pipeline, and the pipe column pipeline is disconnected from the gas production pipeline; In the step S30, the tubing string pipeline is connected to the oil-casing pipeline and both are disconnected from the gas production pipeline; or, the tubing string pipeline is disconnected from the oil-casing pipeline and the gas production pipeline and the tubing string pipeline is connected to an external pressure supply device; or, the tubing string pipeline is disconnected from the oil-casing pipeline and the gas production pipeline, and the oil-casing annulus is pressurized to force gas and liquid to enter the interior of the injection and production tubing string through the bypass one-way valve.

2. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 1, It is characterized in that The surface production and injection pipeline includes a first control valve, a second control valve and a third control valve. The tubing string pipeline is connected to a first pipeline node through the first control valve, the oil casing pipeline is connected to the first pipeline node through the second control valve, and the gas production pipeline is connected to the first pipeline node through the third control valve.

3. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 2, It is characterized in that Open the first control valve and the third control valve, and close the second control valve, to implement step S10; The first control valve is closed, and the second control valve and the third control valve are opened to implement step S20.

4. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 3, It is characterized in that Open the first control valve and the second control valve to connect the tubing string pipeline with the tubing casing pipeline to implement step S30; or, The first control valve and the second control valve are closed to hold the pressure in the casing annulus, forcing the gas and liquid to pass through the bypass one-way valve and enter the lower injection and upper production tubing string, so as to implement step S30.

5. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 4, It is characterized in that The tubing string pipeline is provided with an oil pressure gauge, and the oil casing pipeline is provided with a casing pressure gauge.

6. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 5, It is characterized in that After the casing pressure of the casing pressure gauge is higher than the oil pressure of the oil pressure gauge, step S30 is implemented.

7. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 2, It is characterized in that The surface production and injection pipeline includes a fourth control valve, a fifth control valve and a high-pressure gas source, and the high-pressure gas source serves as the external pressure supply device; The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve; The second pipeline node is connected to the high-pressure gas source through the fourth control valve.

8. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 7, It is characterized in that Open the fifth control valve, the first control valve and the third control valve, and close the second control valve and the fourth control valve to implement step S10; The second control valve and the third control valve are opened, the first control valve and the fifth control valve are closed, and the fourth control valve is continued to be closed to implement the step S20.

9. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 8, It is characterized in that The first control valve and the fourth control valve are opened, and the fifth control valve is continued to be closed, so that the column pipeline is connected to the high-pressure gas source, so as to implement the step S30.

10. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 9, It is characterized in that When the step S30 is implemented, the fifth control valve continues to be closed, and the second control valve and the third control valve remain open to collect gas.

11. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 2, It is characterized in that The surface production and injection pipeline includes a fourth control valve, a fifth control valve, a sixth control valve and a compressor, and the compressor serves as the external pressure supply device; The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve; The second pipeline node is connected to the outlet of the compressor through the fourth control valve; The inlet of the compressor is connected to the first line node via the sixth control valve.

12. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 11, It is characterized in that The first control valve, the fourth control valve, and the sixth control valve are opened, the second control valve is kept open, the fifth control valve is kept closed, and the compressor is started to implement step S30.

13. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 12, It is characterized in that When the step S30 is implemented, the third control valve is opened.

14. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 5, It is characterized in that The injection-down and production-up operation system comprises a liquid level monitoring device, and the liquid level monitoring device is used to monitor the liquid level height in the injection-down and production-up pipe string in the well.

15. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 14, It is characterized in that When the liquid level monitoring device detects that the liquid level in the injection and production upper pipe string drops to a level close to the bypass one-way valve or meets the requirements, the step S30 is stopped.

16. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 14, It is characterized in that The injection and production operation system includes a controller, which is used to control the switching of each control valve according to the monitoring signal of the liquid level monitoring device, the detection signal of the oil pressure gauge and the detection signal of the casing pressure gauge. The liquid level monitoring device is installed at the top of the channel in the injection and production pipe string.

17. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 1, It is characterized in that The outlet end of the one-way valve is connected with a bell mouth.

18. The method for downhole gas-liquid separation and injection and extraction in a gas well according to claim 1, It is characterized in that The injection-down and mining-up method also includes: Step S40, draining the oil pressure; Step S50, normal gas collection; The step S10, the step S20, the step S30, the step S40 and the step S50 are implemented in sequence.

19. A gas well gas-liquid downhole separation injection and production operation system, It is characterized in that The method for downhole gas-liquid separation and injection and extraction in a gas well as described in any one of claims 1 to 18; The injection-down and production-up operation system comprises a ground production-injection pipeline, a wellbore, and an injection-down and production-up pipe string arranged in the wellbore, and an oil casing annulus is formed between the injection-down and production-up pipe string and the wellbore; The injection and production upper tubing string comprises a bypass check valve, a packer and a check valve connected in sequence from top to bottom, the check valve adopts a structure that can be opened downward and closed upward, the packer is used to isolate the oil casing annulus, and the bypass check valve has a one-way conduction structure from the oil casing annulus to the inner cavity of the injection and production upper tubing string; The gas well stratum has a gas production layer and a water injection layer, the gas production layer is located above the water injection layer, and the packer is arranged between the gas production layer and the water injection layer; The surface production and injection pipeline comprises: A pipe string pipeline connected to the inner cavity of the injection and production pipe string; An oil casing pipeline connected to the oil casing annulus; Gas pipeline; The surface production and injection pipeline includes a first control valve, a second control valve and a third control valve. The tubing string pipeline is connected to a first pipeline node through the first control valve, the oil casing pipeline is connected to the first pipeline node through the second control valve, and the gas production pipeline is connected to the first pipeline node through the third control valve.

20. A gas-liquid downhole separation and injection and production system for gas wells. It is characterized in that The method for downhole gas-liquid separation and injection and extraction in a gas well as described in any one of claims 1 to 18; The injection-down and production-up system comprises a surface production-injection pipeline and an injection-down and production-up pipe string, wherein the injection-down and production-up pipe string is used to be arranged in a wellbore and to form an oil casing annulus between the wellbore and the wellbore; The injection and production upper tubing string comprises a bypass check valve, a packer and a check valve connected in sequence from top to bottom, the check valve adopts a structure that can be opened downward and closed upward, the packer is used to isolate the oil casing annulus, and the bypass check valve has a one-way conduction structure from the oil casing annulus to the inner cavity of the injection and production upper tubing string; The packer is used to be arranged in the wellbore and is located between the upper gas production layer and the lower water injection layer; The surface production and injection pipeline comprises: A pipe string pipeline connected to the inner cavity of the injection and production pipe string; An oil casing pipeline connected to the oil casing annulus; Gas pipeline; The surface production and injection pipeline includes a first control valve, a second control valve and a third control valve. The tubing string pipeline is connected to a first pipeline node through the first control valve, the oil casing pipeline is connected to the first pipeline node through the second control valve, and the gas production pipeline is connected to the first pipeline node through the third control valve.

21. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The injection-down and production-up system comprises a liquid level monitoring device, and the liquid level monitoring device is installed on the top of the channel in the injection-down and production-up pipe string.

22. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 21, It is characterized in that The tubing string pipeline is connected to an oil pressure gauge, and the oil casing pipeline is connected to a casing pressure gauge.

23. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 22, It is characterized in that The injection and extraction system includes a controller, which is used to control the switching of each control valve according to the monitoring signal of the liquid level monitoring device, the detection signal of the oil pressure gauge and the detection signal of the casing pressure gauge.

24. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The one-way valve adopts a sliding sleeve ball throwing and releasing structure, and the sliding sleeve shear pins of the one-way valve can be sheared off by throwing a ball.

25. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The one-way valve adopts a structure in which the valve core and the valve body are separated. The valve body is directly connected to the oil pipe coupling of the injection and production pipe string, and the valve core can be repeatedly cast in and out.

26. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The packer has a slip anchoring function and is connected to the oil pipe of the injection and production string by inserting and re-inserting the pipe.

27. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The injection and production pipe string includes oil pipe, drill pipe or small casing.

28. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The power supply of the injection and production system is derived from the large-scale electricity of the well site, a generator, or the wind power and solar power of the well site.

29. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The surface production and injection pipeline includes a fourth control valve, a fifth control valve and a high-pressure gas source, and the high-pressure gas source serves as the external pressure supply device; The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve; The second pipeline node is connected to the high-pressure gas source through the fourth control valve.

30. The gas-liquid downhole separation and injection-upstream production system for gas wells according to claim 20, It is characterized in that The surface production and injection pipeline includes a fourth control valve, a fifth control valve, a sixth control valve and a compressor, and the compressor serves as the external pressure supply device; The column pipeline is connected to the second pipeline node through the first control valve, and the second pipeline node is connected to the first pipeline node through the fifth control valve; The second pipeline node is connected to the outlet of the compressor through the fourth control valve; The inlet of the compressor is connected to the first line node via the sixth control valve.

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