Low pressure gas well fluid recovery device and method

Abstract

This invention discloses a low-pressure gas well fluid retrieval device and method, including a base with a platform having a through hole. A support frame, winch, and explosion-proof control cabinet are fixedly installed on the platform. A top pulley is connected to the top of the support frame, and a load sensor is installed inside the pulley shaft. The support frame is connected via a connecting pipe clamp to a blowout preventer (BOP) assembly that vertically passes through the through hole. An electronic pressure gauge is installed on the outer wall of the BOP assembly. A sealing device and a buffer device are installed inside the BOP assembly from top to bottom. The lower end of the BOP assembly is connected to the BOP via a union. The winch includes a drum and a motor, with the drum coaxially connected to the motor. One end of a steel wire rope is wound around the drum, and the other end passes over the top pulley and connects to the fluid retrieval tool. A data acquisition device is installed on the drum. This invention can monitor the gas well pressure to start and stop equipment and perform fluid retrieval operations, enabling water-flooded gas wells to quickly resume production, reducing operating costs and labor intensity. Furthermore, the fluid retrieval device can be moved to different wellheads for repeated fluid retrieval work, reducing the cost per well.

Description

Technical Field

[0001] This invention belongs to the field of oilfield development technology, and relates to a low-pressure gas well fluid retrieval device, as well as a fluid retrieval method of the aforementioned low-pressure gas well fluid retrieval device. Background Technology

[0002] my country is rich in oil and gas resources, but oil and gas wells are often flooded. Conventional drainage and gas production measures are not ideal and will eventually lead to the shutdown of oil and gas wells due to water flooding.

[0003] The utility model patent with authorization announcement number CN216077072U discloses a non-gas lift precision liquid level control gas production device for low atmospheric pressure gas wells, including a lifting device, a lifting rope, and a retrieval bucket that enters the gas well to retrieve liquid. There is a gap between the outer wall of the retrieval bucket and the inner wall of the casing or the inner wall of the tubing. By retrieving the downhole liquid, the height of the downhole liquid column is reduced, but the liquid drainage efficiency is low and the operation is cumbersome.

[0004] To address the problem of water-flooded gas wells, high-pressure gas lift drainage is currently the most common measure. However, it suffers from high operating costs and short-lived effects, making it unsustainable for long-term gas well production. Some oilfields use pumping units to directly pump water from gas wells, but this suffers from insufficient pump depth and low pump efficiency, resulting in unsatisfactory results. Summary of the Invention

[0005] The purpose of this invention is to provide a low-pressure gas well fluid retrieval device that solves the problems of insufficient drainage depth and slow speed in the prior art.

[0006] The first technical solution adopted in this invention is a low-pressure gas well fluid retrieval device, including a base, a platform with a through hole on the base, a support frame, a winch, and an explosion-proof control cabinet fixedly installed on the platform; a top pulley is connected to the top of the support frame, and a load sensor is installed inside the shaft of the top pulley; the support frame is connected to a blowout preventer assembly that passes vertically through the through hole via a connecting pipe clamp, and an electronic pressure gauge is installed on its outer wall; a sealing device and a buffer device are installed inside the blowout preventer assembly from top to bottom; the lower end of the blowout preventer assembly is connected to the blowout preventer via a union; the winch includes a drum and a motor, the drum and the motor are coaxially connected, one end of a wire rope is wound around the drum, and the other end passes over the top pulley and is connected to the fluid retrieval tool; a data acquisition device is installed on the drum.

[0007] The invention is further characterized by: The sealing device includes a pressure plate, the lower surface of which abuts against a sealing block. The sealing block is formed by four conical blocks with a fan-shaped cross-section. The cross-sectional area of ​​the sealing block gradually decreases from top to bottom. The sealing block is placed in the groove of the inner conical block, and the shape of the groove matches the sealing block. A through hole is opened at the central axis position of the pressure plate and the inner conical block. An electronic pressure gauge is located below the inner conical block. The piston rod of the electric cylinder abuts against the pressure plate downward.

[0008] The buffer device includes a buffer spring and a top plate. The top plate is fixed to the inner wall of the blowout preventer assembly, and the two ends of the buffer spring abut against the inner cone block and the top plate, respectively.

[0009] The control system is installed inside the explosion-proof control cabinet.

[0010] The base is also hinged to a supporting steel frame, which includes two steel structure frames arranged opposite each other, and the two frames are connected by a connecting frame.

[0011] The base is connected to steel rollers at its lower end, and the outer side of the steel rollers is equipped with connecting lugs. A translation track is located below the steel rollers, and a limiter is installed on the translation track. The translation track consists of a pair of parallel tracks, each with an I-shaped cross-section that is narrower at the top and wider at the bottom. Multiple connecting rods perpendicular to the tracks are located between the two tracks. Several bolt holes are spaced apart on the upper part of the translation track, and traction seats are connected to these bolt holes.

[0012] The bottom of the support frame is hinged with several connecting lugs, which are all connected to the fixing seat by bolts. The fixing seat is installed on the platform of the base. The fixing seat has a hollow structure inside, with several pads on the upper surface. The fixing seat has a top height, and a top height through hole is opened at the center of the upper plane.

[0013] The second technical solution adopted in this invention is a fluid retrieval method for a low-pressure gas well fluid retrieval device, specifically including the following steps: S1. Connect the low-pressure gas well fluid retrieval device to the valve at the top of the gas wellhead production tree; S2. When the well pressure meets the conditions for starting the fluid retrieval operation, start the winch to loosen the wire rope and drive the fluid retrieval tool into the gas production tree until the fluid retrieval tool is completely submerged in the accumulated fluid in the well. S3. Liquid accumulated in the well enters the liquid retrieval tool, generating tension on the steel wire rope. The load sensor inside the pulley collects the load data. S4. Control the winch drum to rotate in the opposite direction, pull the wire rope, thereby driving the liquid retrieval tool and the internal liquid upward. When the liquid retrieval tool reaches the wellhead, the liquid is discharged from the gas production pipeline. S5. By monitoring the liquid accumulation in the well, repeat the liquid retrieval action until the liquid retrieval operation is completed.

[0014] The beneficial effects of this invention are: The low-pressure gas well fluid removal device of the present invention uses a winch to drive a steel wire rope and fluid removal tools into the wellbore. It moves back and forth between the fluid accumulation location in the wellbore and the wellhead, and discharges the fluid accumulated in the wellbore multiple times in a quantitative manner. By analyzing data such as gas well pressure and gas-liquid production, the device and fluid removal operation can be started and stopped, enabling water-flooded gas wells to quickly resume production, reducing operating costs and labor intensity. Furthermore, the fluid removal device can be moved to different wellheads to repeat the fluid removal work, reducing the operating cost per well. Attached Figure Description

[0015] Figure 1 This is a front view of the low-pressure gas well fluid retrieval device of the present invention; Figure 2 This is a side view of the low-pressure gas well fluid retrieval device of the present invention; Figure 3 This is a top view of the low-pressure gas well fluid retrieval device of the present invention; Figure 4 This is a schematic diagram of the blowout preventer in the low-pressure gas well fluid retrieval device of the present invention; Figure 5 This is a schematic diagram of the structure of the fixed base in the low-pressure gas well fluid retrieval device of the present invention; Figure 6 This is a schematic diagram of the structure of the fixed seat plate in the low-pressure gas well fluid retrieval device of the present invention.

[0016] In the diagram, 1. Base, 2. Ladder, 3. Railing, 4. Connecting frame, 5. Connecting rod, 6. Blowout preventer, 7. Blowout preventer assembly, 8. Top pulley, 9. Support frame, 10. Wire rope, 11. Connecting lug, 12. Connecting bolt, 13. Fixed seat, 14. Winch, 15. Control box, 16. Bolt hole, 17. Limit switch, 18. Roller, 19. Connecting lug plate, 20. Translation track, 21. Hand chain hoist, 22. Traction seat, 23. Flip cover, 24. Explosion-proof control cabinet, 25. Electric cylinder, 26. Pressure plate, 27. Sealing block, 28. Inner cone block, 29. Electronic pressure gauge, 30. Buffer spring, 31. Top plate, 32. Top height through hole, 33. Top height, 34. Pad plate. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, the low-pressure gas well fluid retrieval device of the present invention is installed above the low-pressure gas well and includes a base 1. The base 1 is provided with a platform with through holes, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 are fixedly installed on the platform.

[0019] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0020] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0021] Working principle of the low-pressure gas well fluid retrieval device of this invention: Data such as wellhead tubing and casing pressure, external pipeline pressure, and gas well production are collected using wellhead pressure gauges and flow meters. Based on existing formulas, the gas well's fluid accumulation status and fluid-carrying production capacity are calculated. When no oil or gas production is detected in the gas well, and the pressure difference between the tubing and casing exceeds the set value determined by engineers based on well analysis and evaluation, the winch 14 motor is activated. This controls the wire rope 10 to slowly lower the fluid-retrieving tool through the channel within the blowout preventer assembly 7, initiating a repeated fluid-retrieving and drainage operation.

[0022] During the fluid retrieval operation, the drum of winch 14 rotates in the forward direction to loosen the wire rope 10. The wire rope 10 drives the fluid retrieval tool through the blowout preventer assembly 7, blowout preventer 6, and gas well production tree in sequence, entering the wellbore and finally sinking below the surface of the accumulated fluid in the wellbore. After the accumulated fluid flows into the retrieval tool, it exerts a pulling force on the wire rope 10. The load sensor inside the pin of the pulley 8 can accurately measure the weight of the accumulated fluid in the fluid retrieval tool by sensing the force exerted on it by the wire rope 10.

[0023] When the fluid retrieval tool is filled with liquid, the winch 14 is reversed to pull the wire rope 10, thereby driving the fluid retrieval tool and the internal liquid upward. When the fluid retrieval tool reaches the wellhead, the internal liquid is discharged through the gas production pipeline of the gas production tree.

[0024] By monitoring the data from the load-bearing sensor and data acquisition device on the pulley 8, the lowering speed, lowering depth, and load on the wire rope 10 are analyzed in real time to determine whether the fluid retrieval tool is working properly. The speed of the fluid retrieval tool in the wellbore is controlled in real time by adjusting the speed of the winch motor 14 to ensure operational safety.

[0025] By monitoring the data from the electronic pressure gauge 29, the internal pressure of the blowout preventer assembly 7 is obtained. The extension or retraction length of the piston rod of the electric cylinder 25 is adjusted in real time, pushing the pressure plate 26 to move up and down. When the pressure plate 26 presses down on the sealing block 27 to hold the wire rope 10, it can prevent gas in the well from escaping between the wire rope 10 and the sealing block 27. If the electronic pressure gauge 29 detects overpressure, it is determined that the pressure in the well is too high. The winch motor 14 is stopped, and the electric cylinder of the blowout preventer 6 is extended at the same time to perform the well shut-in action to ensure operational safety.

[0026] The fluid retrieval method for low-pressure gas well fluid retrieval devices shall be implemented in the following steps: S1. Connect the low-pressure gas well fluid retrieval device to the valve at the top of the gas wellhead production tree; S2. When the well pressure meets the conditions for starting the fluid retrieval operation, start the winch 14 to loosen the wire rope 10, and drive the fluid retrieval tool into the gas production tree until the fluid retrieval tool is completely submerged in the accumulated fluid in the well. S3. Liquid accumulated in the well enters the liquid retrieval tool, generating tension on the steel wire rope 10. The load sensor in the pulley 8 collects the load data. S4. Control the drum of winch 14 to rotate in the opposite direction, pull the wire rope 10, thereby driving the liquid retrieval tool and the internal liquid to move upward. When the liquid retrieval tool moves to the wellhead, the liquid is discharged from the gas production pipeline. S5. By monitoring the liquid accumulation in the well, repeat the liquid retrieval action until the liquid retrieval operation is completed.

[0027] Example 1 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0028] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0029] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0030] like Figure 4 As shown, the blowout preventer assembly 7 is a slender cylinder with a smooth inner wall. The sealing device includes a pressure plate 26, the lower surface of which abuts against a sealing block 27. The sealing block 27 is formed by four conical blocks with a fan-shaped cross-section. The cross-sectional area of ​​the sealing block 27 gradually decreases from top to bottom. The sealing block 27 is placed in the groove of the inner conical block 28, and the shape of the groove matches the sealing block 27. A through hole is opened at the central axis position of the pressure plate 26 and the inner conical block 28. The electronic pressure gauge 29 is located below the inner conical block 28. The piston rod of the electric cylinder 25 abuts against the pressure plate 26 downward.

[0031] The buffer device includes a buffer spring 30 and a top plate 31. The top plate 31 is fixed to the inner wall of the blowout preventer assembly 7. The two ends of the buffer spring 30 abut against the inner cone block 28 and the top plate 31, respectively.

[0032] Example 2 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0033] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0034] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0035] The blowout preventer 6 is driven by an electric cylinder and includes upper and lower gates. The upper gate has a rubber ring in the middle, and the lower gate is a pure steel shear gate.

[0036] The blowout preventer 6 can also be selected from existing hydraulically controlled blowout preventers or orifice-controlled blowout preventers, depending on the wellhead pressure parameters, size, and operational requirements of the gas well.

[0037] Example 3 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0038] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0039] The winch 14 includes a drum, a motor, and an automatic rope arranger. The drum is coaxially connected to the motor. One end of the wire rope 10 is wound around the drum. The drum is equipped with an automatic rope arranger, which has a roller that abuts against the wire rope 10. The roller is equipped with a data acquisition device that can record the number of rotations. The other end of the wire rope 10 passes over the pulley 8 and is connected to the liquid retrieval tool.

[0040] The explosion-proof control cabinet 24 includes a control system. The control system receives real-time monitoring data from instruments such as the gas wellhead pressure gauge, flow meter, weighing sensor, data acquisition device, and electronic pressure gauge 29. It processes the data to determine whether the conditions for starting, repeating, or stopping the action have been met, and sends relevant instructions to the winch 14, electric cylinder 25, and blowout preventer 6.

[0041] Example 4 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0042] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0043] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0044] like Figure 2 The base 1 shown is a further improvement on the base 1. Usually, the liquid retrieval device installed at the wellhead is relatively large in size, making it inconvenient to transport from one gas well to another. Therefore, the base 1 is designed as a detachable structure to facilitate disassembly and transportation.

[0045] The base 1 is also hinged to a supporting steel frame, which includes two steel structure frames arranged opposite each other, and the two frames are connected by a connecting frame 4.

[0046] Example 5 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0047] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0048] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0049] The base 1 is also hinged to a supporting steel frame, which includes two steel structure frames arranged opposite each other, and the two frames are connected by a connecting frame 4.

[0050] The lower end of the base 1 is connected to a steel roller 18. The outer side of the steel roller 18 is provided with a connecting ear plate 19. The steel roller 18 rolls along the translation track 20 laid on the ground.

[0051] The translation track 20 is equipped with a limiter 17, which is fixed in any desired position by pressing the upper surface of the track with bolts.

[0052] The translation track 20 includes a pair of parallel tracks. Each track has an I-shaped cross-section that is narrower at the top and wider at the bottom. Multiple connecting rods perpendicular to the tracks are provided between the two tracks.

[0053] The upper part of the translation track 20 is provided with several bolt holes 16 at intervals, and the traction seat 22 is connected to the bolt holes 16.

[0054] After the fluid removal work of a gas well is completed, remove the connecting frame 4 on the lower base, connect the traction seat 22 and the connecting ear plate 19 with the hand hoist 21, and pull the base 1 along the translation track 20 to the gas production tree of the next gas well in the same well site. Reinstall the connecting frame 4 to fix the base 1, and use multiple limiters to limit the position of the base on the translation track 20 to carry out the fluid removal work of the next gas well.

[0055] Example 6 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0056] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0057] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0058] like Figure 3 As shown, the upper platform of the base 1 is equipped with railings 3 around its perimeter, a flip-up cover 23 is provided on the platform, and a ladder 2 is provided on the side to facilitate personnel going up and down the base and ensure personnel safety.

[0059] Example 7 The low-pressure gas well fluid retrieval device of the present invention includes a base 1, a platform with through holes on the base 1, and a support frame 9, a winch 14 and an explosion-proof control cabinet 24 fixedly installed on the platform.

[0060] The top of the support frame 9 is connected to a pulley 8, and a load sensor is installed inside the shaft of the pulley 8. The support frame 9 is connected to the blowout preventer assembly 7, which is vertically passing through the through hole, via a connecting pipe clamp. An electronic pressure gauge 29 is installed on its outer wall. The blowout preventer assembly 7 is equipped with a sealing device and a buffer device from top to bottom. The lower end of the blowout preventer assembly 7 is connected to the blowout preventer 6 via a union. The blowout preventer 6 is connected to the valve at the top of the gas production tree via a union.

[0061] The winch 14 includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope 10 is wound around the drum, and the other end passes over the pulley 8 and is connected to the liquid retrieval tool. A data acquisition device is installed on the drum.

[0062] like Figure 5 As shown, in this embodiment, the bottom of the support frame 9 is hinged with several connecting lugs 11, and the connecting lugs 11 are all connected to the fixing seat 13 by bolts 12. The fixing seat 13 is installed on the platform of the base 1. The fixed base 13 has a hollow structure, and several pads 34 are provided on the upper surface. The fixed base 13 has a top height 33, and a top height through hole 32 is opened at the center of the upper plane.

[0063] like Figure 6 As shown, the shape of the pad 34 is half of the upper surface of the fixing seat 13.

[0064] When the support frame 9 needs to be adjusted, loosen the connecting bolt 12, adjust the top of the top height 33 upward, and push the connecting lug 11 at the bottom of the support frame 9 through the top height through hole 32. Then, fix the pads 34 of different thicknesses on the upper surface of the fixed seat 13 as needed. When the support frame 9 reaches the required tilt angle, loosen the top height 33 and re-fix the connecting bolt 12 to complete the alignment of the support frame 9 with the wellhead.

Claims

1. A low pressure gas well fluid recovery device, characterized by, Includes a base (1), which is provided with a platform with through holes, and a support frame (9), a winch (14) and an explosion-proof control cabinet (24) are fixedly installed on the platform. The top of the support frame (9) is connected to a pulley (8), and a load sensor is provided inside the shaft of the pulley (8); The support frame (9) is connected to the blowout preventer assembly (7) that passes vertically through the through hole via a connecting pipe clamp. An electronic pressure gauge (29) is provided on its outer wall. A sealing device and a buffer device are provided inside the blowout preventer assembly (7) from top to bottom. The lower end of the blowout preventer assembly (7) is connected to the blowout preventer (6) via a union. The winch (14) includes a drum and a motor. The drum and the motor are coaxially connected. One end of the wire rope (10) is wound around the drum, and the other end passes over the pulley (8) and is connected to the liquid retrieval tool. A data acquisition device is provided on the drum.

2. The low-pressure gas well fluid retrieval device according to claim 1, characterized in that, The sealing device includes a pressure plate (26), the lower surface of the pressure plate (26) abuts against a sealing block (27), the sealing block (27) is surrounded by four conical blocks with a fan-shaped cross-section, the cross-sectional area of ​​the sealing block (27) gradually decreases from top to bottom, the sealing block (27) is placed in the groove of the inner conical block (28), the shape of the groove matches the sealing block (27), and the pressure plate (26) and the inner conical block (28) have through holes at the central axis position; The electronic pressure gauge (29) is located below the inner cone block (28); The piston rod of the electric cylinder (25) abuts against the pressure plate (26) downwards.

3. The low-pressure gas well fluid retrieval device according to claim 2, characterized in that, The buffer device includes a buffer spring (30) and a top plate (31). The top plate (31) is fixed to the inner wall of the blowout preventer assembly (7). The two ends of the buffer spring (30) abut against the inner cone block (28) and the top plate (31) respectively.

4. The low-pressure gas well fluid retrieval device according to claim 3, characterized in that, The explosion-proof control cabinet (24) houses the control system.

5. The low-pressure gas well fluid retrieval device according to claim 1, characterized in that, The base (1) is also hinged to a supporting steel frame at its bottom. The supporting steel frame includes two steel structure frames arranged opposite each other, and the two frames are connected by a connecting frame (4).

6. The low-pressure gas well fluid retrieval device according to claim 1, characterized in that, The lower end of the base (1) is connected to a steel roller (18), and the outer side of the steel roller (18) is provided with a connecting ear plate (19).

7. The low-pressure gas well fluid retrieval device according to claim 6, characterized in that, The steel roller (18) is provided with a translation track (20), and a limiter (17) is provided on the translation track (20). The translation track (20) includes a pair of parallel tracks. The cross-section of each track is an I-shaped structure that is narrow at the top and wide at the bottom. Multiple connecting rods perpendicular to the tracks are provided between the two tracks.

8. The low-pressure gas well fluid retrieval device according to claim 7, characterized in that, The upper part of the translation track (20) is provided with several bolt holes (16) at intervals, and the traction seat (22) is connected to the bolt holes (16).

9. The low-pressure gas well fluid retrieval device according to claim 1, characterized in that, The bottom of the support frame (9) is hinged with several connecting lugs (11), and the connecting lugs (11) are all connected to the fixing seat (13) by bolts (12). The fixing seat (13) is installed on the platform of the base (1). The fixed base (13) has a hollow structure inside, and several pads (34) are provided on the upper surface. The fixed base (13) has a top height (33), and a top height through hole (32) is opened at the center of the upper plane.

10. A fluid retrieval method for a low-pressure gas well fluid retrieval device, characterized in that, The low-pressure gas well fluid retrieval device as described in any one of claims 1 to 9 is implemented according to the following steps: S1. Connect the low-pressure gas well fluid retrieval device to the valve at the top of the gas wellhead production tree; S2. When the well pressure meets the conditions for starting the fluid retrieval work, start the winch (14) to loosen the wire rope (10) and drive the fluid retrieval tool into the gas production tree until the fluid retrieval tool is completely submerged in the well fluid. S3. The accumulated liquid in the well enters the liquid retrieval tool, which generates tension on the wire rope (10). The load sensor in the pulley (8) collects the load data. S4. Control the drum of the winch (14) to rotate in the opposite direction and pull the wire rope (10), thereby driving the liquid retrieval tool and the internal liquid to move upward. When the liquid retrieval tool moves to the wellhead, the liquid is discharged from the gas production pipeline of the gas production tree. S5. By monitoring the liquid accumulation in the well, repeat the liquid retrieval action until the liquid retrieval operation is completed.

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