Ultra-long drill hole multi-section type synchronous pressure injection and displacement coal seam gas system

Abstract

An inlet end of a high-pressure gas injection pump is connected with a gas outlet of a gas storage tank through a high-pressure gas supply pipeline, and an outlet end of the high-pressure gas injection pump is connected with a gas inlet end of a high-pressure gas injection pipeline; the inlet end of the first high-pressure water injection pump is connected with the water outlet of the water storage tank through a high-pressure water supply pipeline; the hole sealing device comprises a hole sealing capsule, a fracturing pipeline and a water injection pipeline; the inlet end of the second high-pressure water injection pump is connected with the water outlet of the water storage tank through a second high-pressure water supply pipeline, the outlet end of the second high-pressure water injection pump is connected with the water inlet end of a second high-pressure water injection pipeline, and the water outlet end of the second high-pressure water injection pipeline is connected with a hole sealing capsule; the water inlet end of the main filling pipeline is connected with the gas outlet end of the high-pressure gas injection pipeline and the water outlet end of the first high-pressure water injection pipeline through a tee joint, and the water outlet end of the main filling pipeline is connected with the fracturing pipeline. The system is high in gas displacement efficiency, and the operation process and time of ultra-long drill hole fracturing can be effectively shortened.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal mine safety, and in particular relates to an ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas. Background Art

[0002] Gas extraction is a fundamental technical measure to achieve gas disaster prevention and control. In China, the permeability of coal seams is improved mainly through technical measures such as high-pressure hydraulic fracturing (or displacement), water splitting (or punching), coal seam pre-splitting blasting (explosive blasting, CO2 phase change blasting, high-voltage electric pulse fracturing, etc.). However, the current coal seam gas displacement system and method used to improve the permeability of coal seams is difficult to promote the desorption of gas in nano-scale pores. At the same time, the fracturing effect for ultra-long boreholes is not ideal, and the current system operation requires a relatively complicated process and takes a long time. Therefore, the current system for displacing coal seam gas cannot completely solve the problem of low coal seam gas extraction efficiency.

[0003] Therefore, it is urgent to provide an ultra-long borehole multi-stage synchronous pressure injection system for displacing coal seam gas, so as to effectively improve the ultra-long borehole fracturing effect and solve the problem of low coal seam gas extraction rate. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the utility model provides an ultra-long borehole multi-stage synchronous pressure injection system for displacing coal seam gas. The system has high gas displacement efficiency and can effectively reduce the operating process and time of ultra-long borehole fracturing. It is particularly suitable for ultra-long borehole gas displacement operations and can provide important technical guarantees for improving gas displacement efficiency.

[0005] In order to achieve the above-mentioned purpose, the utility model provides an ultra-long drilling multi-stage synchronous pressure injection displacement coal seam gas system, including a high-pressure gas injection unit, a high-pressure water injection unit and a fracturing displacement unit;

[0006] The high-pressure gas injection unit comprises a gas storage tank, a high-pressure gas injection pump and a high-pressure stop valve 2; the gas storage tank is filled with gas; the inlet end of the high-pressure gas injection pump is connected to the gas outlet of the gas storage tank through a high-pressure gas supply pipeline, and its outlet end is connected to the gas inlet end of the high-pressure gas injection pipeline; the high-pressure stop valve 2 is connected in series to the middle section of the high-pressure gas injection pipeline;

[0007] The high-pressure water injection unit comprises a water storage tank, a high-pressure water injection pump 1 and a high-pressure stop valve 3; the water storage tank is filled with water; the inlet end of the high-pressure water injection pump 1 is connected to the water outlet of the water storage tank through a high-pressure water supply pipeline 1, and the outlet end is connected to the water inlet end of the high-pressure water injection pipeline 1; the high-pressure stop valve 3 is connected in series to the middle section of the high-pressure water injection pipeline 1;

[0008] The fracturing displacement unit includes a sealing device, a high-pressure water injection pump 2, a high-pressure stop valve 4, a main filling pipeline, a tee, a high-pressure stop valve 1, a drainage pipeline and a high-pressure stop valve 5; the sealing device includes a sealing capsule, a fracturing pipeline and a water injection pipeline; a plurality of sealing capsules are distributed in sequence along the length direction, and a fracturing section is formed between two adjacent sealing capsules; the fracturing pipeline passes through a plurality of sealing capsules in sequence, is not connected to the inner cavity of the sealing capsules, and its water inlet end is exposed to the outside of the sealing capsule at the head end, and the fracturing pipeline is provided with a water outlet in the portion corresponding to each fracturing section; the number of the plurality of water injection pipelines is arranged in correspondence with the plurality of fracturing sections, and the two ends of each water injection pipeline are respectively connected to the water injection ports of two adjacent sealing capsules; the sealing device is arranged Installed in the drill hole; the inlet end of the high-pressure water injection pump 2 is connected to the water outlet of the water storage tank through the high-pressure water supply pipeline 2, and its outlet end is connected to the water inlet end of the high-pressure water injection pipeline 2, and the water outlet end of the high-pressure water injection pipeline 2 is through-connected to the water injection port of the sealing capsule located at the head end; the high-pressure stop valve 4 is connected in series to the high-pressure water injection pipeline 2; the water inlet end of the main filling pipeline is connected to the air outlet end of the high-pressure air injection pipeline and the water outlet end of the high-pressure water injection pipeline 1 respectively through a tee, and the water outlet end of the main filling pipeline is through-connected to the water inlet end of the fracturing pipeline; the high-pressure stop valve 1 is connected in series to the main filling pipeline; the drainage pipeline is arranged away from the tee than the high-pressure stop valve 1, one end of the drainage pipeline is through-connected to the main filling pipeline, and the high-pressure stop valve 5 is connected in series to the drainage pipeline.

[0009] Furthermore, in order to facilitate switching the on / off state of the high-pressure gas supply pipeline, the high-pressure gas injection unit also includes a high-pressure stop valve six, and the high-pressure stop valve six is ​​connected in series to the high-pressure gas supply pipeline.

[0010] Furthermore, in order to facilitate switching the on / off state of the high-pressure water supply pipeline 1, the high-pressure water injection unit also includes a high-pressure stop valve 7, and the high-pressure stop valve 7 is connected in series to the high-pressure water supply pipeline 1.

[0011] Furthermore, in order to improve the fracturing effect, the length of the fracturing section is 10 to 15 m.

[0012] Furthermore, in order to facilitate real-time observation of the injection pressure, the fracturing displacement unit also includes a pressure gauge 1, a pressure gauge 2 and a high-pressure stop valve 8. The pressure gauge 1 is located between the high-pressure stop valve 1 and the drainage pipeline, and is connected to the fracturing pipeline; the pressure gauge 2 is farther away from the high-pressure water injection pump 2 than the high-pressure stop valve 4, and is connected to the high-pressure water injection pipeline 2; in order to facilitate switching the on and off state of the high-pressure water supply pipeline 2, the high-pressure stop valve 8 is connected in series to the middle section of the high-pressure water supply pipeline 2.

[0013] As a preference, the number of the sealed capsules is five.

[0014] In the utility model, multiple sealing capsules are connected with multiple water injection pipelines and then fracturing pipelines are installed in the multiple sealing capsules to form a sealing device, which can be installed in an ultra-long borehole and can simultaneously form multiple fracturing sections in the ultra-long borehole. In this way, when high-pressure water is supplied to the fracturing pipeline in the sealing device, multiple fracturing sections can be fracturing simultaneously, which can not only significantly improve the fracturing efficiency, but also help to improve the fracturing effect, which is conducive to building a complex gas migration network. At the same time, it is conducive to significantly reducing the operation process of ultra-long borehole fracturing and reducing the workload of fracturing. The inlet end of the main filling pipeline is connected to the gas outlet end of the high-pressure gas injection pipeline and the water outlet end of the high-pressure water injection pipeline one through a tee, and the high-pressure stop valve two and the high-pressure stop valve three are connected in series on the high-pressure gas injection pipeline and the high-pressure water injection pipeline one, respectively, which can facilitate the quick switching of the gas injection and water injection states, so that high-pressure water injection and gas injection operations can be conveniently realized. Connecting a high-pressure water injection pump in series between the water storage tank and the water inlet of the high-pressure water injection pipeline can facilitate the use of the high-pressure water injection pump to pressurize the water, and then use the high-pressure water to efficiently impact the coal seam, so as to obtain a better permeability enhancement and fracturing effect, which is conducive to obtaining a larger extension of fractures in multiple fracturing sections simultaneously. Connecting a high-pressure air injection pump in series between the gas storage tank and the air inlet of the high-pressure air injection pipeline can facilitate the use of the high-pressure air injection pump to pressurize the gas, and then use the high-pressure gas to synchronously and efficiently impact the coal seams in multiple fracturing sections, thereby fully solving the water lock effect generated after water injection, which is conducive to promoting the migration of gas in coal. Therefore, this system can realize multi-stage synchronous pressure injection of fluid to displace CH in nano-scale pores. 4 , which is conducive to efficiently driving the migration of multiphase media.

[0015] The system has high gas displacement efficiency and can effectively reduce the operating procedures and time of ultra-long borehole fracturing. It is particularly suitable for ultra-long borehole gas displacement operations and can provide important technical support for improving gas displacement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a super-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas in the utility model.

[0017] In the figure: 1, coal seam, 2, sealing capsule, 3, fracturing pipeline, 4, water injection pipeline, 5, sealing device, 6, pressure gauge one, 7, fracturing section, 8, high-pressure stop valve five, 9, high-pressure stop valve six, 10, high-pressure stop valve seven, 11, main filling pipeline, 12, high-pressure stop valve one, 13, high-pressure water injection pump one, 14, water storage tank, 15, high-pressure air injection pump, 16, air storage tank, 17, high-pressure water injection pump two, 18, three-way, 19, high-pressure stop valve two, 20, high-pressure gas supply pipeline, 21, high-pressure gas injection pipeline, 22, high-pressure stop valve three, 23, high-pressure water supply pipeline one, 24, high-pressure water injection pipeline one, 25, high-pressure water supply pipeline two, 26, high-pressure water injection pipeline two, 27, high-pressure stop valve four, 28, drilling hole, 29, drainage pipeline, 30, pressure gauge two, 31, high-pressure stop valve eight. DETAILED DESCRIPTION

[0018] The utility model will be further described below in conjunction with the accompanying drawings.

[0019] like Figure 1 As shown, the utility model provides an ultra-long drilling multi-stage synchronous pressure injection displacement coal seam gas system, including a high-pressure gas injection unit, a high-pressure water injection unit and a fracturing displacement unit;

[0020] The high-pressure gas injection unit includes a gas storage tank 16, a high-pressure gas injection pump 15 and a high-pressure stop valve 19; the gas storage tank 16 is filled with gas; the inlet end of the high-pressure gas injection pump 15 is connected to the gas outlet of the gas storage tank 16 through a high-pressure gas supply pipeline 20, and its outlet end is connected to the gas inlet end of the high-pressure gas injection pipeline 21; the high-pressure stop valve 19 is connected in series to the middle section of the high-pressure gas injection pipeline 21;

[0021] The high-pressure water injection unit includes a water storage tank 14, a high-pressure water injection pump 13 and a high-pressure stop valve 3 22; the water storage tank 14 is filled with water; the inlet end of the high-pressure water injection pump 13 is connected to the water outlet of the water storage tank 14 through a high-pressure water supply pipeline 1 23, and its outlet end is connected to the water inlet end of the high-pressure water injection pipeline 1 24; the high-pressure stop valve 3 22 is connected in series to the middle section of the high-pressure water injection pipeline 1 24;

[0022] The fracturing displacement unit includes a sealing device 5, a high-pressure water injection pump 2 17, a high-pressure stop valve 4 27, a main filling pipeline 11, a tee 18, a high-pressure stop valve 12, a drainage pipeline 29 and a high-pressure stop valve 5 8; the sealing device 5 includes a sealing capsule 2, a fracturing pipeline 3 and a water injection pipeline 4; a plurality of sealing capsules 2 are distributed in sequence along the length direction, and a fracturing section 7 is formed between two adjacent sealing capsules 2; the fracturing pipeline 3 passes through a plurality of sealing capsules 2 in sequence, and is not connected to the inner cavity of the sealing capsule 2, and its water inlet end is exposed to the outside of the sealing capsule 2 at the head end, and the fracturing pipeline 3 is provided with a water outlet in the portion corresponding to each fracturing section 7; the number of the plurality of water injection pipelines 4 is arranged in correspondence with the plurality of fracturing sections 7, and the two ends of each water injection pipeline 4 are respectively connected to the water injection ports of two adjacent sealing capsules 2; the sealing device 5 is installed in the borehole 28 The inlet end of the high-pressure water injection pump 17 is connected to the water outlet of the water storage tank 14 through the high-pressure water supply pipeline 25, and the outlet end is connected to the water inlet end of the high-pressure water injection pipeline 26, and the outlet end of the high-pressure water injection pipeline 26 is connected to the water injection port of the sealing capsule 2 at the head end; the high-pressure stop valve 27 is connected in series to the high-pressure water injection pipeline 26; the water inlet end of the main filling pipeline 11 is connected to the high-pressure injection pipeline 11 through the tee 18. The air outlet end of the air pipeline 21 is connected to the water outlet end of the high-pressure water injection pipeline 24, and the water outlet end of the main filling pipeline 11 is connected to the water inlet end of the fracturing pipeline 3; the high-pressure stop valve 12 is connected in series to the main filling pipeline 11; the drainage pipeline 29 is arranged farther away from the tee 18 than the high-pressure stop valve 12, one end of the drainage pipeline 29 is connected to the main filling pipeline 11, and the high-pressure stop valve 58 is connected in series to the drainage pipeline 11.

[0023] In order to facilitate switching the on / off state of the high-pressure gas supply pipeline, the high-pressure gas injection unit also includes a high-pressure stop valve 69, which is connected in series to the high-pressure gas supply pipeline 20.

[0024] In order to facilitate switching the on / off state of the high-pressure water supply pipeline 1, the high-pressure water injection unit also includes a high-pressure stop valve 7 10, and the high-pressure stop valve 7 10 is connected in series to the high-pressure water supply pipeline 1 23.

[0025] In order to improve the fracturing effect, the length of the fracturing section 7 is 10 to 15 m.

[0026] In order to facilitate real-time observation of the injection pressure, the fracturing displacement unit also includes a pressure gauge 16, a pressure gauge 230 and a high-pressure stop valve 831. The pressure gauge 16 is located between the high-pressure stop valve 12 and the drainage pipeline 29, and is connected to the main filling pipeline 11; the pressure gauge 230 is farther away from the high-pressure water injection pump 217 than the high-pressure stop valve 427, and is connected to the high-pressure water injection pipeline 26; in order to facilitate switching the on and off state of the high-pressure water supply pipeline 25, the high-pressure stop valve 831 is connected in series to the middle section of the high-pressure water supply pipeline 25.

[0027] As a preference, the number of the sealing capsules 2 is five.

[0028] Method of use: first construct a borehole 28 in the coal seam 11, and then determine the number of sealing capsules 2 according to the needs of the operation; then, use multiple sealing capsules 2, fracturing pipelines 3 and multiple water injection pipelines 4 to assemble a sealing device 5, and detect the activity performance of each sealing capsule 2 in the sealing device 5 to ensure that it can work normally; put the sealing device 5 into a predetermined fracturing section in the borehole 28 and fix it, forming a fracturing section 7 between two adjacent sealing capsules 2. Open the high-pressure stop valve eight 31, open the high-pressure stop valve four 27, start the high-pressure water injection pump two 17 to inject water into the sealing capsule 2, and the water entering the inner cavity of the sealing capsule 2 at the head end enters the remaining sealing capsules 2 in sequence through the water injection pipeline 4. When each sealing capsule 2 is fully injected with water, the sealing capsule 2 is fully expanded and the borehole 28 is fully blocked. During this process, the pressure of the high-pressure water injection pipeline two 26 is observed by the pressure gauge two 30. When the pressure reaches the set range, it is determined that the sealing capsule 2 reaches a fully sealed state. At this time, close the high-pressure stop valve four 27, close the high-pressure water injection pump two 17, close the high-pressure stop valve eight 31, and complete the sealing operation. Open high-pressure stop valve seven 10, open high-pressure stop valve three 22, open high-pressure stop valve one 12, keep high-pressure stop valve five 8 in a closed state, keep high-pressure stop valve two 19 in a closed state, open high-pressure water injection pump one 13, pump out the water in the water storage tank 14 and pressurize it, and then inject it into the fracturing pipeline 3 through the high-pressure water injection pipeline one 24 and the main filling pipeline 11. The high-pressure water entering the fracturing pipeline 3 is sprayed out from the water outlet and acts on the fracturing section 7 to perform fracturing operations on the coal seam. After the set time, close the high-pressure stop valve three 22, close the high-pressure water injection pump one 13, close the high-pressure stop valve seven 10, open the high-pressure stop valve five 8, use the drainage pipeline 29 to discharge the excess water in the borehole 28, and then close the high-pressure stop valve five 8. Open the high-pressure stop valve six 9, open the high-pressure stop valve two 19, open the high-pressure stop valve one 12, start the high-pressure gas injection pump 15 to perform the high-pressure gas injection operation, and after the set time, close the high-pressure stop valve six 9, close the high-pressure gas injection pump 15, close the high-pressure stop valve two 19, and close the high-pressure stop valve one 12. The quantity and specifications of the above-mentioned fracturing section 7 and the sealing capsule 2 need to be selected according to the design length and aperture of the borehole 28. At the same time, the water leakage of the tunnel wall should be monitored in real time during the implementation process. If there is too much water leakage, the water injection fracturing should be stopped and the sealing condition should be checked.

[0029] In the utility model, multiple sealing capsules are connected with multiple water injection pipelines and then fracturing pipelines are installed in the multiple sealing capsules to form a sealing device, which can be installed in an ultra-long borehole and can simultaneously form multiple fracturing sections in the ultra-long borehole. In this way, when high-pressure water is supplied to the fracturing pipeline in the sealing device, multiple fracturing sections can be fracturing simultaneously, which can not only significantly improve the fracturing efficiency, but also help to improve the fracturing effect, which is conducive to building a complex gas migration network. At the same time, it is conducive to significantly reducing the operation process of ultra-long borehole fracturing and reducing the workload of fracturing. The inlet end of the main filling pipeline is connected to the gas outlet end of the high-pressure gas injection pipeline and the water outlet end of the high-pressure water injection pipeline one through a tee, and the high-pressure stop valve two and the high-pressure stop valve three are connected in series on the high-pressure gas injection pipeline and the high-pressure water injection pipeline one, respectively, which can facilitate the quick switching of the gas injection and water injection states, so that high-pressure water injection and gas injection operations can be conveniently realized. Connecting a high-pressure water injection pump in series between the water storage tank and the water inlet of the high-pressure water injection pipeline can facilitate the use of the high-pressure water injection pump to pressurize the water, and then use the high-pressure water to efficiently impact the coal seam, so as to obtain a better permeability enhancement and fracturing effect, which is conducive to obtaining a larger extension of fractures in multiple fracturing sections simultaneously. Connecting a high-pressure air injection pump in series between the gas storage tank and the air inlet of the high-pressure air injection pipeline can facilitate the use of the high-pressure air injection pump to pressurize the gas, and then use the high-pressure gas to synchronously and efficiently impact the coal seams in multiple fracturing sections, thereby fully solving the water lock effect generated after water injection, which is conducive to promoting the migration of gas in coal. Therefore, this system can realize multi-stage synchronous pressure injection of fluid to displace CH in nano-scale pores. 4 , which is conducive to efficiently driving the migration of multiphase media.

[0030] The system has high gas displacement efficiency and can effectively reduce the operating procedures and time of ultra-long borehole fracturing. It is particularly suitable for ultra-long borehole gas displacement operations and can provide important technical support for improving gas displacement efficiency.

Claims

1. An ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas, comprising a high-pressure gas injection unit and a high-pressure water injection unit, characterized in that: Also included is a fracturing displacement unit; The high-pressure gas injection unit comprises a gas storage tank (16), a high-pressure gas injection pump (15) and a second high-pressure stop valve (19); the gas storage tank (16) is filled with gas; the inlet end of the high-pressure gas injection pump (15) is connected to the gas outlet of the gas storage tank (16) through a high-pressure gas supply pipeline (20), and the outlet end thereof is connected to the gas inlet end of the high-pressure gas injection pipeline (21); the second high-pressure stop valve (19) is connected in series to the middle section of the high-pressure gas injection pipeline (21); The high-pressure water injection unit comprises a water storage tank (14), a high-pressure water injection pump (13) and a high-pressure stop valve (22); the water storage tank (14) is filled with water; the inlet end of the high-pressure water injection pump (13) is connected to the water outlet of the water storage tank (14) through a high-pressure water supply pipeline (23), and the outlet end is connected to the water inlet end of the high-pressure water injection pipeline (24); the high-pressure stop valve (22) is connected in series to the middle section of the high-pressure water injection pipeline (24); The fracturing displacement unit comprises a sealing device (5), a second high-pressure water injection pump (17), a fourth high-pressure stop valve (27), a main filling pipeline (11), a three-way valve (18), a first high-pressure stop valve (12), a drainage pipeline (29) and a fifth high-pressure stop valve (8); the sealing device (5) comprises a sealing capsule (2), a fracturing pipeline (3) and a water injection pipeline (4); a plurality of sealing capsules (2) are sequentially distributed along the length direction, and a fracturing section (7) is formed between two adjacent sealing capsules (2); The fracturing pipeline (3) passes through the plurality of sealing capsules (2) in sequence, is not connected to the inner cavity of the sealing capsules (2), and its water inlet end is exposed to the outside of the sealing capsule (2) located at the head end, and the fracturing pipeline (3) is provided with a water outlet at the portion corresponding to each fracturing section (7); the number of the plurality of water injection pipelines (4) is arranged in correspondence with the plurality of fracturing sections (7), and the two ends of each water injection pipeline (4) are respectively connected to the water injection ports of two adjacent sealing capsules (2); the sealing device (5) is installed in the borehole (28); the inlet end of the high-pressure water injection pump (17) is connected to the water outlet of the water storage tank (14) through the high-pressure water supply pipeline (25), and the outlet end is connected to the water inlet end of the high-pressure water injection pipeline (26); the water outlet end of the high-pressure water injection pipeline (26) is connected to the water injection port of the sealing capsule (2) at the head end; the high-pressure stop valve (27) is connected in series to the high-pressure water injection pipeline (26); the water inlet end of the main filling pipeline (11) is connected to the high-pressure gas injection pipeline (26) through the tee (18) The air outlet end of the pipeline (21) is connected to the water outlet end of the high-pressure water injection pipeline (24), and the water outlet end of the main filling pipeline (11) is connected to the water inlet end of the fracturing pipeline (3); the high-pressure stop valve (12) is connected in series to the main filling pipeline (11); the drainage pipeline (29) is arranged farther away from the tee (18) than the high-pressure stop valve (12), one end of the drainage pipeline (29) is connected in series to the main filling pipeline (11), and the high-pressure stop valve (5) (8) is connected in series to the drainage pipeline (29).

2. The ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas according to claim 1 is characterized in that: The high-pressure gas injection unit also includes a high-pressure stop valve six (9), and the high-pressure stop valve six (9) is connected in series to the high-pressure gas supply pipeline (20).

3. The ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas according to claim 1 is characterized in that: The high-pressure water injection unit also includes a high-pressure stop valve seven (10), and the high-pressure stop valve seven (10) is connected in series to the high-pressure water supply pipeline one (23).

4. The ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas according to claim 2 or 3, characterized in that: The length of the fracturing section (7) is 10 to 15 m.

5. The ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas according to claim 4 is characterized in that: The fracturing displacement unit further comprises a pressure gauge 1 (6), a pressure gauge 2 (30) and a high-pressure stop valve 8 (31); the pressure gauge 1 (6) is located between the high-pressure stop valve 1 (12) and the drainage pipeline (29), and is connected to the main filling pipeline (11); the pressure gauge 2 (30) is farther away from the high-pressure water injection pump 2 (17) than the high-pressure stop valve 4 (27), and is connected to the high-pressure water injection pipeline 2 (26); the high-pressure stop valve 8 (31) is connected in series to the middle section of the high-pressure water supply pipeline 2 (25).

6. The ultra-long drilling multi-stage synchronous pressure injection system for displacing coal seam gas according to claim 5, characterized in that: The number of the sealing capsules (2) is five.

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