Combined liquid drainage system and method for prolonging life cycle of water-producing gas well

Abstract

The invention belongs to the technical field of oil and gas production of oil and gas fields, and particularly provides a combined liquid drainage system and method for prolonging the life cycle of a water-producing gas well. A tower is installed on a wellhead, a control system is installed at the bottom of the tower, a steel wire winch lifting device is connected to the upper portion of the tower through an operation platform, and a blowout prevention device is installed on a Christmas tree; the underground swabbing tool and the underground plunger tool are sequentially installed in the well from top to bottom, the steel wire winch lifting device comprises a steel wire and a power mechanism, one end of the steel wire is connected with the power mechanism, and the other end of the steel wire penetrates through the blowout preventer and the Christmas tree and then is connected with the underground swabbing tool; the control system is electrically connected with the steel wire winch lifting device and the blowout preventer. The problems that a plunger is difficult to lift for liquid drainage in the later production period of an existing water-producing gas well and water is rapidly flooded after recovery are solved, a good water drainage and gas recovery effect can be achieved, the life cycle of the gas well is prolonged, and the final recovery efficiency of the gas well is improved.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field production technology, specifically relating to a combined drainage system and method for extending the life cycle of water-producing gas wells. Background Technology

[0002] Throughout the life cycle of a water-producing gas well, as production continues, the well's production capacity decreases. When it falls below the critical fluid carrying capacity, fluid can easily accumulate in the wellbore, leading to a significant reduction in gas well production or even shutdown. In such cases, fluid drainage measures are needed to remove the accumulated fluid and thus extend the gas well's life cycle.

[0003] The Changqing tight gas reservoir is a typical water-producing gas reservoir, currently containing over 15,000 liquid-laden gas wells, accounting for more than 50% of the total number of wells. The main drainage and gas production technologies are plunger lift, velocity tubing, and bubble drainage. Among these, bubble drainage and velocity tubing have reduced liquid-carrying effectiveness as well production decreases, and are primarily used for wells with daily gas production exceeding 5000 m³ / h. 3 For gas wells, plunger lift is the most widely applicable, capable of meeting daily production needs of 2000m³. 3 The above describes the production process of gas wells with fluid drainage. However, because the plunger gas lift relies on the gas well's own energy for intermittent fluid drainage, when the gas well's production capacity further decreases, there are instances where the plunger lifts the fluid column in the wellbore to the middle of the tubing, but falls back to the bottom of the well due to insufficient energy. This repeated occurrence leads to severe fluid accumulation and water flooding in the gas well, resulting in production shutdown.

[0004] For wells with severe fluid accumulation and plugging, pumping is a forced fluid removal and production recovery process. A pumping tool is connected to a steel wire and lowered below the fluid level in the tubing. The fluid in the wellbore is then lifted using the power of a surface winch, which helps the plugged gas lift well resume production. However, because the gas well itself has low energy, the plug will soon be unable to drain the fluid, and the gas well will quickly flood and shut down again, failing to achieve the goal of extending the gas well's life cycle.

[0005] Chinese patent document CN117846550A discloses an integrated tubing string for gas lift, mechanical pumping combined lifting, and non-killing well operations. This tubing string structure includes a rod-type pump lifting system, a gas lift system, and a non-killing well operation device. Oil flow is achieved by installing an oil outlet joint and a fixed valve seat under the sucker rod. Different operating states are achieved by setting a central rod and a guide shield. This tubing string effectively combines gas-proof lift, gas-operated lift, and non-killing well operations, solving the problems of poor adaptability to existing gas-proof production and low well-killing success rates in high-yield gas wells. However, this document does not solve the problems of difficulty in lifting and draining the plunger in the later stages of production in existing water-producing gas wells and rapid water flooding after resumption of production. Summary of the Invention

[0006] The present invention provides a combined drainage system and method for extending the life cycle of water-producing gas wells, aiming to overcome the problems in the prior art where the plunger is difficult to lift and drain in the later stage of production and rapid flooding after production resumption.

[0007] To this end, the present invention provides a combined drainage system for extending the life cycle of water-producing gas wells. A Christmas tree is installed at the wellhead. The combined drainage system includes a tower, an operating platform, a control system, a wireline winch hoisting device, a blowout preventer (BOP), downhole pumping tools, and a downhole plunger tool. The tower is installed at the wellhead, the control system is installed at the bottom of the tower, the operating platform is installed on the tower, the wireline winch hoisting device is installed on the operating platform, the BOP is installed on the Christmas tree, and the downhole pumping tool and the downhole plunger tool are installed sequentially from top to bottom inside the well. The wireline winch hoisting device includes a wireline and a power mechanism. One end of the wireline is connected to the power mechanism, and the other end passes through the BOP and the Christmas tree and connects to the downhole pumping tool. The control system is electrically connected to both the wireline winch hoisting device and the BOP.

[0008] Preferably, the power mechanism includes a motor and a wire winch, the power output end of the motor is connected to the wire winch, steel wire is wound on the wire winch, and an operating platform is connected to the bottom of the wire winch.

[0009] Preferably, the wire rope winch lifting device further includes a pulley, which is connected to the wire rope winch, and the other end of the wire rope is connected to the downhole pumping tool after passing through the pulley and the blowout preventer.

[0010] Preferably, the wire winch lifting device further includes a sensor, which is connected to a pulley and the wire contacts the sensor.

[0011] Preferably, the sensor includes a depth sensor and a tension sensor, both of which are in contact with the steel wire.

[0012] Preferably, the blowout preventer includes a blowout preventer box, a blowout preventer, a hydraulic control device, a blowout preventer pipe, and valves. The blowout preventer box, blowout preventer, blowout preventer pipe, and wellhead are connected in sequence from top to bottom. The hydraulic control device is connected to the tower. The blowout preventer box and the blowout preventer are both connected to the hydraulic control device. The blowout preventer pipe and the wellhead are connected by valves.

[0013] Preferably, the downhole pumping tool includes an anti-overhead tool and a pumping plunger, with the anti-overhead tool connected to the pumping plunger at the bottom and a steel wire connected to the upper end of the anti-overhead tool.

[0014] Preferably, the downhole plunger tool includes a single-flow buffer limiter, a plunger, and a bottom-hole limiter, which are installed sequentially from top to bottom.

[0015] Preferably, the single-flow buffer limiter is provided with a ball seat and a valve ball, with the valve ball resting on the ball seat.

[0016] A combined drainage method for extending the lifespan of a water-producing gas well includes the following steps:

[0017] 1) After the well is opened, the plunger lifts the fluid at the bottom of the well to above the single-flow buffer limiter. The fluid above the single-flow buffer limiter causes the valve ball to fall back to the ball seat.

[0018] 2) After shutting in the well, the plunger falls above the bottom limit switch, and the wire rope winch hoisting device lowers the downhole pumping tool above the single-flow buffer limit switch via the wire rope.

[0019] 3) After the well is opened, the wire rope hoisting device lifts the downhole pumping tool into the blowout preventer via the wire rope to discharge the accumulated liquid above the single-flow buffer limiter.

[0020] 4) Keep the valve fully open so that the plunger lifts the fluid at the bottom of the well to above the single-flow buffer limiter; repeat steps 3) to 4) to complete the drainage.

[0021] The beneficial effects of this invention are:

[0022] 1. The combined drainage system and method for extending the lifespan of water-producing gas wells provided by this invention includes a tower, an operating platform, a control system, a wire rope winch hoisting device, a blowout preventer, downhole pumping tools, and a downhole plunger tool. For gas wells with low energy levels in the later stages of production, the downhole plunger tool performs plunger gas lift drainage, while the wire rope winch hoisting device and the downhole pumping tool perform pumping drainage. By combining the plunger gas lift process and the pumping process, the wellbore liquid is lifted in stages. This method can reduce the running distance of the plunger and pumping tools, thereby reducing wear and tear, extending tool replacement time by more than two times, reducing liquid loss, and improving drainage efficiency. The combined drainage system and method of this invention can achieve better drainage and gas production effects, solving the problems of difficulty in plunger lifting and drainage in the later stages of existing water-producing gas wells and rapid water flooding after resumption of production, extending the lifespan of gas wells, and improving the final recovery rate of gas wells.

[0023] 2. The combined drainage system and method for extending the life cycle of water-producing gas wells provided by this invention includes a downhole plunger tool comprising a single-flow buffer limiter, a plunger, and a bottom-hole limiter. The downhole plunger tool is a bottom-first stage plunger for lifting fluid, which can fully utilize reservoir energy to first lift the bottom fluid to the upper part of the single-flow buffer limiter. The single-flow buffer limiter has the function of unidirectional flow of gas and liquid from bottom to top, preventing liquid backflow and ensuring that the liquid can remain at the upper part of the single-flow buffer limiter.

[0024] 3. The combined drainage system and method for extending the life cycle of water-producing gas wells provided by this invention includes a downhole pumping tool comprising an anti-overhead tool and a pumping plunger, which facilitates the lifting of liquid remaining above the single-flow buffer limiter to the surface by the anti-overhead tool and the pumping plunger. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of a combined drainage system that extends the lifespan of water-producing gas wells;

[0027] Figure 2 This is a flowchart of the combined drainage method for extending the life cycle of a water-producing gas well, as described in Example 7.

[0028] Explanation of reference numerals in the attached drawings: 1. Tower; 2. Operating platform; 3. Control system; 4. Wire rope winch hoisting device; 5. Blowout preventer; 6. Downhole pumping tool; 7. Downhole plunger tool;

[0029] 401. Motor; 402. Braking system; 403. Wire winch; 404. Depth sensor; 405. Pulley; 406. Tension sensor; 407. Wire;

[0030] 501. Blowout Preventer Box; 502. Blowout Preventer; 503. Hydraulic Control Device; 504. Blowout Preventer Tube; 505. Valve; 506. Pressure Sensor;

[0031] 601. Anti-backlash tool; 602. Pump plunger;

[0032] 701. Single-flow buffer limiter; 702. Plunger; 703. Bottom hole limiter. Detailed Implementation

[0033] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0034] Example 1:

[0035] like Figure 1 As shown, a combined drainage system for extending the lifespan of a water-producing gas well is disclosed. A Christmas tree is installed at the wellhead. The combined drainage system includes a tower 1, an operating platform 2, a control system 3, a wire rope winch hoisting device 4, a blowout preventer 5, a downhole pumping tool 6, and a downhole plunger tool 7. The tower 1 is installed at the wellhead, the control system 3 is installed at the bottom of the tower 1, the operating platform 2 is installed on the tower 1, the wire rope winch hoisting device 4 is installed on the operating platform 2, the blowout preventer 5 is installed on the Christmas tree, and the downhole pumping tool 6 and the downhole plunger tool 7 are installed sequentially from top to bottom inside the well. The wire rope winch hoisting device 4 includes a wire 407 and a power mechanism. One end of the wire 407 is connected to the power mechanism, and the other end passes through the blowout preventer 5 and the Christmas tree before connecting to the downhole pumping tool 6. The control system 3 is electrically connected to both the wire rope winch hoisting device 4 and the blowout preventer 5.

[0036] Specifically, for gas wells with low energy levels in the later stages of production, the tower 1 is fixed next to the wellhead to facilitate the installation of the operating platform 2, control system 3, wire rope winch hoisting device 4, and blowout preventer 5, making reasonable use of space. The control system 3 controls the wire rope winch hoisting device 4 to raise and lower the downhole pumping tool 6 to achieve pumping and drainage. The wire rope 407 can transmit long-distance loads, has a high safety factor, is safe and reliable in use, is lightweight, easy to carry and transport, and has high tensile strength, fatigue strength, and impact toughness. Under high-speed working conditions, it is wear-resistant, shock-resistant, and has good operational stability. It also has good corrosion resistance and can work normally in harsh environments with various harmful media.

[0037] The downhole plunger tool 7 performs plunger gas lift for fluid drainage, while the wire rope winch hoisting device 4 and the downhole pumping tool 6 perform pumping for fluid drainage. By combining the plunger gas lift process and the pumping process, the wellbore fluid is lifted in stages. This method can reduce the running distance of the plunger and pumping tool, thereby reducing wear and extending tool replacement time by more than two times, reducing fluid loss, and improving drainage efficiency. The combined drainage system and method of this invention can achieve better drainage and gas production effects, solving the problems of difficulty in plunger lifting and drainage in the later stage of existing water-producing gas wells and rapid water flooding after resumption of production, extending the life cycle of gas wells, and improving the final recovery rate of gas wells.

[0038] Example 2:

[0039] Based on Embodiment 1, the power mechanism includes a motor 401 and a wire winch 403. The power output end of the motor 401 is connected to the wire winch 403. A wire 407 is wound on the wire winch 403, and the operating platform 2 is connected to the bottom of the wire winch 403.

[0040] Specifically, the motor 401 is connected to the wire winch 403. The motor 401 drives the winch 403 to pull the wire 407 to lift and lower the downhole pumping tool 6, completing the pressurized retrieval and drainage. The structure is simple and the operation is stable.

[0041] Preferably, the wire rope winch lifting device 4 further includes a pulley 405, which is connected to the wire rope winch 403, and the other end of the wire 407 is connected to the downhole pumping tool 6 after passing through the pulley 405 and the blowout preventer 5.

[0042] Specifically, the pulley 405 can be used to change the position of the steel wire 407, and the lifting and lowering are time-saving and labor-saving, resulting in high work efficiency.

[0043] Preferably, the wire winch lifting device 4 further includes a sensor, which is connected to a pulley 405 and the wire 407 contacts the sensor.

[0044] Specifically, the sensor can obtain relevant data about the steel wire 407. The sensor can be selected according to actual needs to facilitate the operation of the downhole pumping tool 6.

[0045] Preferably, the sensor includes a depth sensor 404 and a tension sensor 406, both of which are in contact with the steel wire 407.

[0046] Specifically, the depth sensor 404 facilitates real-time recording of the depth data of the downhole pumping tool 6 connected to the lower end of the wire 407, and the tension sensor 406 facilitates the recording of the tension data of the wire 407.

[0047] Preferably, the wire winch lifting device 4 further includes a braking system 402, which is connected to a motor 401.

[0048] Specifically, the braking system 402 facilitates the control of the start and stop of the motor 401.

[0049] Example 3:

[0050] Based on Embodiment 2, the blowout preventer 5 includes a blowout preventer box 501, a blowout preventer 502, a hydraulic control device 503, a blowout preventer pipe 504, and a valve 505. The blowout preventer box 501, the blowout preventer 502, the blowout preventer pipe 504, and the wellhead are connected sequentially from top to bottom. The hydraulic control device 503 is connected to the tower 1. The blowout preventer box 501 and the blowout preventer 502 are both connected to the hydraulic control device 503. The blowout preventer pipe 504 and the wellhead are connected through the valve 505.

[0051] Specifically, the steel wire 407 passes sequentially through the pulley 405, blowout preventer box 501, blowout preventer 502, and blowout preventer pipe 504 before connecting to the downhole pumping tool 6. The hydraulic control device 503 facilitates the monitoring and control of the hydraulic pressure of the blowout preventer box 501 and blowout preventer 502. The blowout preventer 5 ensures the wellhead is sealed during the retrieval and drainage process, guaranteeing the safety of the operation.

[0052] Preferably, the valve 505 is an electrically controlled valve, which offers a high degree of automation.

[0053] Preferably, a pressure sensor is installed on the wellhead for easy monitoring of hydraulic pressure.

[0054] Example 4:

[0055] Based on Embodiment 3, the downhole pumping tool 6 includes an anti-overhead tool 601 and a pumping plunger 602. The anti-overhead tool 601 is connected to the pumping plunger 602 at the bottom, and the steel wire 407 is connected to the upper end of the anti-overhead tool 601.

[0056] Specifically, the anti-overhead tool 601 and the suction plunger 602 facilitate the retrieval and lifting of liquid remaining on the upper part of the single-flow buffer limiter 701 to the ground, and the structure is simple.

[0057] Example 5:

[0058] Based on Example 4, the downhole plunger tool 7 includes a single-flow buffer limiter 701, a plunger 702, and a bottom hole limiter 703, which are installed sequentially from top to bottom.

[0059] Specifically, the downhole plunger tool 7 is a bottom first-stage plunger for fluid lifting, which can fully utilize reservoir energy to first lift the bottom fluid to the upper part of the single-flow buffer limiter 701. The single-flow buffer limiter 701 has the function of unidirectional flow of gas and liquid from bottom to top, preventing liquid backflow and ensuring that the liquid can stay in the upper part of the single-flow buffer limiter 701.

[0060] Preferably, the single-flow buffer limiter 701 is provided with a ball seat and a valve ball, with the valve ball resting on the ball seat.

[0061] Specifically, the single-flow buffer limiter 701 is equipped with a ball seat and a valve ball. After the lower plunger 702 moves up to the single-flow buffer limiter 701, after a period of production, the liquid entering the upper part of the single-flow buffer limiter 701 begins to fall back. The valve ball falls onto the ball seat, limiting the liquid from falling below the single-flow buffer limiter 701, thus preventing the liquid from falling back.

[0062] Preferably, the control system 3 is electrically connected to the motor 401, depth sensor 404, tension sensor 406, hydraulic control device 503, valve 505, and pressure sensor 506 respectively.

[0063] Example 6:

[0064] Based on Example 5, a combined drainage method for extending the life cycle of a water-producing gas well includes the following steps:

[0065] 1) After the well is opened, the plunger 702 lifts the liquid at the bottom of the well to above the single-flow buffer limiter 701, and the liquid above the single-flow buffer limiter 701 causes the valve ball to fall back to the ball seat.

[0066] 2) After the well is shut in, the plunger 702 falls above the bottom limiter 703, and the wire rope winch hoisting device 4 lowers the downhole pumping tool 6 above the single-flow buffer limiter 701 via the wire rope 407.

[0067] 3) After the well is opened by controlling the opening of valve 505, the wire rope winch hoisting device 4 uses wire rope 407 to lift the downhole pumping tool 6 into the blowout preventer 504 and discharge the accumulated liquid above the single-flow buffer limiter 701.

[0068] 4) Keep valve 505 fully open so that plunger 702 lifts the fluid at the bottom of the well to above the single-flow buffer limiter 701; repeat steps 3) to 4) to complete the drainage.

[0069] This invention combines plunger gas lift and pumping processes for gas wells with low energy levels in the later stages of production, using a staged lifting method to raise wellbore fluid. This method reduces the travel distance of the plunger and pumping tools, thereby reducing wear and extending tool replacement time by more than double. Furthermore, conventional pumping processes involve long-distance retrieval and drainage from the well bottom to the wellhead, resulting in significant leakage. This invention, through a first-stage plunger at the bottom, fully utilizes reservoir energy to lift the bottom fluid to the upper part of a single-flow buffer limiter. The single-flow buffer limiter has a unidirectional flow function from bottom to top, preventing backflow and ensuring the fluid remains at the upper part of the single-flow buffer limiter, where it is then lifted to the surface by the second-stage pumping tool, i.e., the downhole pumping tool 6. The application of the first-stage plunger technology can significantly reduce the second-stage pumping and retrieval stroke, reduce liquid loss, and improve drainage efficiency. This combined drainage system and method can achieve better drainage and gas production effects, solving the problems of the plunger being difficult to lift and drain in the later stage of existing water-producing gas wells and rapid water flooding after resumption of production, extending the life cycle of gas wells and improving the final recovery rate of gas wells.

[0070] Example 7:

[0071] Based on Example 6, such as Figure 2 As shown, a combined drainage method for extending the lifespan of a water-producing gas well includes the following steps:

[0072] 1) Install the tower 1, operating platform 2, control system 3, wire rope winch hoisting device 4, and blowout preventer 5 at the wellhead;

[0073] 2) Deploy the bottom stop device 703 at the bottom of the tubing using the wire winch 403, and then deploy the plunger 702.

[0074] 3) Deploy a single-flow buffer limiter 701 at the middle position of the oil pipe;

[0075] 4) The wire rope winch 403 connects to the downhole pumping tool 6 and remains inside the blowout preventer 504, controlling the blowout preventer box 501 to maintain a seal;

[0076] 5) After the well is opened, the plunger 702 at the bottom lifts the liquid at the bottom of the well to above the single-flow buffer limiter 701, and the valve ball falls back to the ball seat under the action of the liquid column;

[0077] 6) After the well is shut in, the plunger 702 falls above the bottom limiter 703, and the wire rope winch 403 is controlled to lower the downhole pumping tool 6 to above the single-flow buffer limiter 701, and the wire rope winch 403 stops running.

[0078] 7) After opening the well, control the valve 505 (electric valve) to lift the downhole pumping tool 6 into the blowout preventer 504 to discharge the liquid above the single-flow buffer limiter 701. Control the blowout preventer box 501 to completely seal the wire through the control system 3.

[0079] 8) Keep control valve 505 (electric valve) fully open to ensure that the bottom plunger 702 lifts the bottom fluid to above the single-flow buffer limiter 701.

[0080] 9) Operate the wells according to the above switching cycle to achieve long-term liquid discharge and gas production from water-producing gas wells.

[0081] In the description of this invention, it should be understood that if terms such as "upper," "inner," or "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting the invention.

[0082] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A combined drainage system for extending the lifespan of water-producing gas wells, wherein a Christmas tree is installed at the wellhead, characterized in that: The combined drainage system includes a tower (1), an operating platform (2), a control system (3), a wire rope winch hoisting device (4), a blowout preventer (5), a downhole pumping tool (6), and a downhole plunger tool (7). The tower (1) is installed at the wellhead, the control system (3) is installed at the bottom of the tower (1), the operating platform (2) is installed on the tower (1), the wire rope winch hoisting device (4) is installed on the operating platform (2), the blowout preventer (5) is installed on the Christmas tree, and the downhole pumping tool (6) and the downhole plunger tool (7) are installed sequentially from top to bottom in the well. The wire rope winch hoisting device (4) includes a wire (407) and a power mechanism. One end of the wire (407) is connected to the power mechanism, and the other end of the wire (407) passes through the blowout preventer (5) and the Christmas tree and is connected to the downhole pumping tool (6). The control system (3) is electrically connected to the wire rope winch hoisting device (4) and the blowout preventer (5).

2. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 1, characterized in that: The power mechanism includes a motor (401) and a wire winch (403). The power output end of the motor (401) is connected to the wire winch (403). A wire (407) is wound on the wire winch (403), and an operating platform (2) is connected to the bottom of the wire winch (403).

3. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 2, characterized in that: The wire winch lifting device (4) also includes a pulley (405), which is connected to the wire winch (403). The other end of the wire (407) is connected to the downhole pumping tool (6) after passing through the pulley (405) and the blowout preventer (5).

4. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 3, characterized in that: The wire winch lifting device (4) also includes a sensor, which is connected to a pulley (405) and the wire (407) contacts the sensor.

5. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 4, characterized in that: The sensor includes a depth sensor (404) and a tension sensor (406), both of which are in contact with the steel wire (407).

6. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 1, characterized in that: The blowout preventer (5) includes a blowout preventer box (501), a blowout preventer (502), a hydraulic control device (503), a blowout preventer pipe (504), and a valve (505). The blowout preventer box (501), the blowout preventer (502), the blowout preventer pipe (504), and the Christmas tree are connected in sequence from top to bottom. The hydraulic control device (503) is connected to the tower (1). The blowout preventer box (501) and the blowout preventer (502) are both connected to the hydraulic control device (503). The blowout preventer pipe (504) and the Christmas tree are connected by the valve (505).

7. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 1, characterized in that: The downhole pumping tool (6) includes an anti-overhead tool (601) and a pumping plunger (602). The anti-overhead tool (601) is connected to the pumping plunger (602) at the bottom, and a steel wire (407) is connected to the upper end of the anti-overhead tool (601).

8. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 1, characterized in that: The downhole plunger tool (7) includes a single-flow buffer limiter (701), a plunger (702), and a bottom-hole limiter (703), which are installed sequentially from top to bottom.

9. The combined drainage system for extending the lifespan of water-producing gas wells as described in claim 8, characterized in that: The single-flow buffer limiter (701) is provided with a ball seat and a valve ball, with the valve ball resting on the ball seat.

10. A combined drainage method for extending the lifespan of a water-producing gas well, characterized in that: Includes the following steps: 1) After the well is opened, the plunger (702) lifts the liquid at the bottom of the well to above the single-flow buffer limiter (701), and the liquid above the single-flow buffer limiter (701) causes the valve ball to fall back to the ball seat. 2) After the well is shut in, the plunger (702) falls above the bottom limiter (703), and the wire winch hoisting device (4) lowers the downhole pumping tool (6) above the single-flow buffer limiter (701) via the wire (407). 3) After the well is opened by controlling the opening of the valve (505), the wire rope winch hoisting device (4) lifts the downhole pumping tool (6) into the blowout preventer (504) through the wire rope (407) to discharge the accumulated liquid above the single-flow buffer limiter (701); 4) Keep valve (505) fully open so that plunger (702) lifts the bottom fluid to above single-flow buffer limiter (701); repeat steps 3) to 4) to complete the drainage.

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