Gas well swabbing and draining device and swabbing and draining method thereof

Abstract

The invention discloses a gas well swabbing and draining device and a swabbing and draining method thereof, and relates to the technical field of drainage and gas recovery equipment.The gas well swabbing and draining device comprises a production oil pipe, a continuous oil pipe and a drainage pipe, the swabbing liquid discharge plunger comprises a connecting cylinder, and a pressure control spring is arranged at the axis position of the connecting cylinder; the first end of the piston with the long rod is fixed to the connecting cylinder through a shear pin with a fixed shear value; and the pressure relief channel is arranged on the outer side wall of the connecting cylinder. According to the gas well swabbing and draining device, the technical problems that a swabbing and draining plunger in an existing gas well swabbing and draining device is difficult to maintain automatic draining, and a continuous oil pipe and the swabbing and draining plunger are damaged due to too large downward pulling force are solved; when the pressure difference between the upper end position of the swabbing and liquid discharging plunger and the lower end position of the swabbing and liquid discharging plunger is larger than a first design value, accumulated liquid can be discharged into the gas well through the first center channel, and the downward pulling force borne by the coiled tubing and the swabbing and liquid discharging plunger is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of water drainage and gas production equipment, and in particular to a gas well pumping and drainage device and a pumping and drainage method thereof. Background Art

[0002] As production time increases, the number of inefficient wells will further increase, and the pressure to maintain stable production in gas fields will gradually increase. Among them, wellbore liquid accumulation is the main cause of inefficient wells. Therefore, it is necessary to drain the wellbore liquid to improve the production efficiency of shale gas fields. Among the existing technologies, pipe string drainage gas production technology, gas lift drainage gas production technology, plunger lift drainage gas production technology, and foam drainage gas production technology are the main drainage gas production processes in shale gas fields.

[0003] However, as production time increases, many gas wells still fail to effectively restore production capacity even with the aforementioned treatment technologies. For one thing, the pumping and drainage plungers in existing gas well pumping and drainage systems struggle to maintain self-draining. When excessive fluid accumulates above the pumping and drainage plungers, the coiled tubing and the plungers can be subject to excessive downward force, potentially damaging them. Furthermore, accumulated fluid in the horizontal sections of some gas wells is difficult to drain, hindering the full recovery of gas energy within the wells. Therefore, a gas well pumping and drainage system and method are proposed to address these issues. Summary of the Invention

[0004] The purpose of the present invention is to provide a gas well pumping and drainage device, which solves the technical problem that the pumping and drainage plunger in the existing gas well pumping and drainage device is difficult to maintain autonomous drainage, and when too much liquid accumulates above the pumping and drainage plunger, the continuous oil pipe and the pumping and drainage plunger are easily damaged due to excessive downward force.

[0005] To achieve the above-mentioned object, the present invention provides a gas well pumping and drainage device, comprising:

[0006] Production tubing, used to transport chemical raw materials in the gas well and provide an operating space for the coiled tubing, with an annular cavity formed between the coiled tubing and the production tubing;

[0007] A pumping and draining plunger is connected to the inlet end of the coiled tubing, and the pumping and draining plunger includes:

[0008] A connecting cylinder, wherein a first central passage is provided at an axial position of the connecting cylinder, and a pressure control spring is provided at a second end of the first central passage;

[0009] A piston with an extended rod, wherein the first end of the piston with an extended rod is inserted into the first central channel, the first end of the piston with an extended rod is fixedly connected to the connecting cylinder via a shear pin with a fixed shear value, the second end of the piston with an extended rod abuts against the pressure control spring, and a second central channel is provided at the axial position of the piston with an extended rod;

[0010] A sealed cavity is provided at the first end of the connecting tube, and a steel ball is provided in the sealed cavity;

[0011] The pressure relief channel is provided on the outer side wall of the connecting tube. When the steel ball is located at the position of the pressure relief channel, the pressure relief channel can be connected to the first end of the first central channel.

[0012] Preferably, a rubber cylinder center rod is provided at the first end of the connecting cylinder, the second end of the rubber cylinder center rod is connected to the first end of the connecting cylinder, and a third center channel is provided at the axial position of the rubber cylinder center rod, and the third center channel is connected to the second center channel.

[0013] Preferably, the first end of the connecting tube is provided with a first assembly groove, and the outer side wall of the second end of the center rod of the rubber tube is sleeved with a plurality of first sealing rings, and the outer side wall of the first sealing ring fits into the first assembly groove.

[0014] Preferably, a sealing rubber sleeve is sleeved on the outer side wall of the rubber sleeve center rod. When the liquid level of the accumulated liquid in the annular cavity is higher than the liquid level of the accumulated liquid in the gas well, the outer side wall of the sealing rubber sleeve fits with the inner side wall of the production oil pipe.

[0015] Preferably, the first end of the center rod of the rubber sleeve is connected to a first joint, the first joint is connected to the coiled tubing through a connector, and a fourth center channel is provided at the axial position of the first joint, and the fourth center channel is connected to the third center channel.

[0016] Preferably, the outer side wall of the connecting cylinder is provided with a plurality of pin holes, the outer side wall of the first end of the long rod piston is coaxially provided with an annular groove, and the shear pin passes through the pin hole and is clamped to connect to the annular groove.

[0017] Preferably, the piston with a long rod includes: a piston part and a long rod part that are integrally arranged, the piston part abuts the pressure control spring, a positioning hole is provided on the outer wall of the long rod part, the positioning hole is connected to a pre-tightening pin, and the pre-tightening pin can reciprocate in the pressure relief channel along the axial direction of the connecting cylinder.

[0018] Preferably, a second joint is provided at the first end of the connecting tube, the end of the second joint abuts against the pressure control spring, and a fifth central channel is provided at the axial position of the second joint, and the fifth central channel is connected to the first central channel.

[0019] Accordingly, the technical solution of the present invention further provides a gas well pumping and drainage method, which is applied to any of the gas well pumping and drainage devices described above, and the gas well pumping and drainage method comprises:

[0020] Controlling the coiled tubing to enter the gas well, and controlling the coiled tubing to drive the pumping and drainage plunger to move downward at a designed speed in a corresponding well section in the gas well;

[0021] After the pumping and draining plunger is lowered to a preset position in the gas well and remains stationary for a certain period of time, the accumulated liquid in the gas well passes through the first central channel and the second central channel in sequence and enters the annular cavity;

[0022] After the liquid level in the production tubing reaches a certain level, the coiled tubing is controlled to drive the pumping and drainage plunger to lift the coiled tubing at the designed speed in the corresponding well section of the gas well until the pumping and drainage plunger moves to the wellhead position of the gas well and remains stationary for a certain period of time, completing a single pumping and drainage operation.

[0023] Preferably, the step of controlling the coiled tubing to drive the pumping and drainage plunger to lift the coiled tubing at a designed speed in the corresponding well section further comprises:

[0024] When the pressure at the first end of the pumping and drainage plunger is greater than the pressure at the second end of the pumping and drainage plunger, and the pressure difference between the first end of the pumping and drainage plunger and the second end of the pumping and drainage plunger is greater than a first design value, the shear pin breaks, the piston with the long rod loses its limit and slides a distance away from the first end of the first central channel under the action of pressure until the steel ball is located at the position of the pressure relief channel. At this time, the pressure relief channel is connected to the first end of the first central channel, and a part of the accumulated liquid in the annular cavity is discharged into the gas well through the first central channel, thereby completing the pressure relief;

[0025] When the pressure at the first end of the pumping and draining plunger drops to a second design value, the piston with a long rod slides toward the first end of the first center channel under the supporting force of the pressure control spring until the pressure relief channel is no longer connected to the first center channel, thereby preventing further leakage of the accumulated liquid in the annular cavity.

[0026] Compared with the above background technology, the present invention provides a gas well pumping and drainage device, which has the following beneficial effects:

[0027] (1) In the process of controlling the continuous oil pipe to drive the pumping and drainage plunger to lift, when the pressure at the first end position of the pumping and drainage plunger is greater than the pressure at the second end position of the pumping and drainage plunger, and the pressure difference between the first end position of the pumping and drainage plunger and the second end position of the pumping and drainage plunger is greater than the first design value, the shear pin breaks, causing the piston with the long rod to lose its limit and slide a distance away from the first end of the first center channel under the action of pressure until the steel ball is located at the position of the pressure relief channel. The pressure relief channel is connected to the first end of the first center channel, and a part of the accumulated liquid is discharged into the gas well through the first center channel to complete the pressure relief, effectively preventing excessive accumulation of liquid at the first end of the pumping and drainage plunger, reducing the downward pull force on the continuous oil pipe and the pumping and drainage plunger, and playing a role in protecting the continuous oil pipe and the pumping and drainage plunger. Furthermore, when the pressure above the pumping and drainage plunger drops to a second design value, the piston with the long rod slides upward under the support force of the pressure control spring until the pressure relief channel is no longer connected to the first central channel. The forces at both ends of the piston with the long rod achieve pressure balance, preventing further leakage of the accumulated fluid in the production tubing, ensuring the reliable function of the pumping and drainage plunger, and further ensuring smooth pumping and drainage of the gas well. The gas well pumping and drainage method adopted in the present invention also has the above beneficial effects.

[0028] (2) In the present invention, the continuous oil pipe is controlled to drive the pumping and drainage plunger to a preset position in the gas well. The pumping and drainage operation can be carried out without destroying the original production pipe string and the wellhead device, and the construction efficiency is higher. When the pumping and drainage plunger is located in the accumulated liquid, the pressure at the second end of the pumping and drainage plunger is greater than the pressure at the first end of the pumping and drainage plunger. Under the action of pressure, the accumulated liquid in the gas well passes through the first central channel and the second central channel in sequence into the annular cavity. Even when the pumping and drainage plunger is lowered to the horizontal section in the gas well, the accumulated liquid in the horizontal section of the gas well can still enter the annular cavity smoothly, which can adapt to the pumping and drainage of low-pressure gas wells and ultra-deep horizontal gas wells, thereby ensuring that the gas energy in the gas well can be fully collected. The overall gas well pumping and drainage device has a wider range of application and better pumping and drainage effect. The gas well pumping and drainage method adopted in the present invention also has the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 A schematic diagram of the working principle of the gas well pumping and drainage device provided in an embodiment of the present invention;

[0031] Figure 2 A schematic cross-sectional view of a pumping and draining plunger provided in an embodiment of the present invention.

[0032] Specifically, 100-gas well; 200-sucking and drainage plunger; 210-connecting tube; 211-pressure control spring; 212-sealing chamber; 213-steel ball; 214-pressure relief channel; 220-piston with long rod; 221-second center channel; 222-shear pin; 223-preload pin; 224-third sealing ring; 230-rubber cylinder center rod; 231-third center channel; 232-first sealing ring; 233-second sealing ring; 240-first joint; 241-fourth center channel; 250-sealing rubber cylinder; 260-second joint; 261-fifth center channel; 300-production tubing; 400-continuous tubing; 500-annulus cavity; 600-driving equipment. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In order to enable those skilled in the art to better understand the solutions of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] like Figure 1 As shown, to achieve the above-mentioned objectives, the present invention provides a pumping and drainage device for a gas well 100, comprising: a production tubing 300, a coiled tubing 400, and a pumping and drainage plunger 200. The production tubing 300 is used to transport chemical raw materials within the gas well 100 and provides an operating space for the coiled tubing 400. The inlet end of the coiled tubing 400 is connected to the pumping and drainage plunger 200. A driving device 600 drives and controls the inlet end of the coiled tubing 400 into the production tubing 300, forming an annulus 500 between the coiled tubing 400 and the production tubing 300. The annulus 500 is located at the first end of the pumping and drainage plunger 200 and can accommodate a certain amount of accumulated liquid. Driven by the coiled tubing 400, the pumping and drainage plunger 200 can slide freely within the production tubing 300.

[0036] like Figure 2As shown, the pumping and drainage plunger 200 includes a connecting tube 210. A first central channel is provided at the axial position of the connecting tube 210. The first central channel runs through the connecting tube 210. A pressure control spring 211 is provided at the second end of the first central channel. The length direction of the pressure control spring 211 is consistent with the length direction of the connecting tube 210. It should be noted that the first end of the pressure control spring 211 is freely retractable, and the second end of the pressure control spring 211 is fixedly disposed in the first central channel.

[0037] A long-rod piston 220 is coaxially arranged in the first central channel, and the first end of the long-rod piston 220 is inserted into the first central channel, and the second end of the long-rod piston 220 is fixedly connected to the connecting tube 210 by a shear pin 222 with a fixed shear value. The second end of the long-rod piston 220 abuts the first end of the pressure control spring 211, and a second central channel 221 is provided at the axial position of the long-rod piston 220. When the pumping and drainage plunger 200 is lowered to a preset position in the gas well 100, the pumping and drainage plunger 200 is located in the accumulated liquid, and the pressure at the second end of the pumping and drainage plunger 200 is greater than the pressure at the first end of the pumping and drainage plunger 200. The accumulated liquid in the gas well 100 passes through the first and second central channels 221 in sequence and enters the annulus cavity 500. When the continuous oil tubing 400 drives the pumping and drainage plunger 200 to be lifted to the wellhead position of the gas well 100, the accumulated liquid can be further discharged.

[0038] A sealing chamber 212 is provided at the first end of the connecting tube 210, and a steel ball 213 is disposed within the sealing chamber 212. The steel ball 213 is located at the first end of the piston with an extended rod 220. The sealing chamber 212, the steel ball 213, and the piston with an extended rod 220 cooperate to form a one-way liquid flow valve. Specifically, when accumulated liquid in the gas well 100 sequentially enters the first and second central channels 221 and then the annulus cavity 500, the steel ball 213 is held away from the first end of the second central channel 221 by the accumulated liquid, ensuring that the accumulated liquid continues to enter the annulus cavity 500. In addition, when the pumping and drainage plunger 200 is lowered to the horizontal section in the gas well 100, since the pumping and drainage plunger 200 is located in the accumulated liquid, the pressure at the second end position of the pumping and drainage plunger 200 is greater than the pressure at the first end position of the pumping and drainage plunger 200. The accumulated liquid in the horizontal section of the gas well 100 can still enter the annular cavity 500 smoothly, and can adapt to the pumping and drainage of low-pressure gas wells 100 and ultra-deep horizontal gas wells 100, thereby ensuring that the gas energy in the gas well 100 can be fully collected. The overall gas well 100 pumping and drainage device has a wider range of application and a better pumping and drainage effect. It should be noted that in the process of the continuous oil pipe 400 driving the pumping and drainage plunger 200 to lift, the steel ball 213 can block the first end of the second center channel 221 under the pressure of the accumulated liquid, preventing the accumulated liquid in the annular cavity 500 from leaking from the second center channel 221, and ensuring that the accumulated liquid in the annular cavity 500 is smoothly lifted to the wellhead position for discharge.

[0039] A pressure relief channel 214 is provided on the outer wall of the connecting tube 210. The length direction of the pressure relief channel 214 is consistent with the axial direction of the connecting tube 210. When the steel ball 213 is located at the position of the pressure relief channel 214, the pressure relief channel 214 can be connected to the first end of the first center channel. At this time, the accumulated liquid in the annular cavity 500 enters the pressure relief channel 214 from the second center channel 221. Specifically, in the process of controlling the continuous oil tubing 400 to drive the pumping and drainage plunger 200 to rise, when the pressure at the first end position of the pumping and drainage plunger 200 is greater than the pressure at the second end position of the pumping and drainage plunger 200, and the pressure difference between the first end position of the pumping and drainage plunger 200 and the second end position of the pumping and drainage plunger 200 is greater than the first design value, the shear pin 222 breaks, causing the piston 220 with the long rod to lose its limit and slide a distance away from the first end of the first central channel under the action of pressure until the steel ball 213 is located at the position of the pressure relief channel 214. The pressure relief channel 214 is connected to the first end of the first central channel, and a part of the accumulated liquid is discharged into the gas well 100 through the first central channel, completing the pressure relief, effectively preventing excessive liquid accumulation at the first end of the pumping and drainage plunger 200, reducing the downward pull on the continuous oil tubing 400 and the pumping and drainage plunger 200, and playing a role in protecting the continuous oil tubing 400 and the pumping and drainage plunger 200.

[0040] It should be noted that the magnitude of the first design value is also the magnitude of the force required to break the shear pin 222. Therefore, the magnitude of the first design value can be adjusted by selecting shear pins 222 with different shear values. Generally, by controlling the liquid level within the annulus cavity 500 and the pressure differential between the first end and the second end of the swabbing and drainage plunger 200, the coiled tubing 400 and the swabbing and drainage plunger 200 are protected from damage due to excessive pressure, thereby preventing the shear pin 222 from breaking.

[0041] During use, the continuous oil tubing 400 is controlled to enter the gas well 100, and the continuous oil tubing 400 is controlled to drive the pumping and drainage plunger 200 to move downward in the corresponding well section in the gas well 100 at a designed speed until the pumping and drainage plunger 200 is lowered to a preset position in the gas well 100. The pumping and drainage plunger 200 is located in the accumulated liquid. By controlling the continuous oil tubing 400 to drive the pumping and drainage plunger 200 to be lowered to the preset position in the gas well 100, the pumping and drainage operation can be carried out without destroying the original production tubing and wellhead equipment, and the construction efficiency is higher. After the pumping and drainage plunger 200 is in the preset position, the pressure at the second end position of the pumping and drainage plunger 200 is greater than the pressure at the first end position of the pumping and drainage plunger 200, and the accumulated liquid in the gas well 100 passes through the first central channel and the second central channel 221 in turn and enters the annulus cavity 500; after it remains stationary for a certain period of time and the liquid level of the accumulated liquid in the production tubing 300 reaches a certain amount, the continuous tubing 400 is controlled to drive the pumping and drainage plunger 200 to lift the continuous tubing 400 at the designed speed in the corresponding well section in the gas well 100 until the pumping and drainage plunger 200 moves to the wellhead position of the gas well 100 and remains stationary for a certain period of time, and a single pumping and drainage is completed.

[0042] In one embodiment of the present invention, a rubber cylinder center rod 230 is provided at the upper end of the connecting cylinder 210, and the second end of the rubber cylinder center rod 230 is connected to the first end of the connecting cylinder 210. Specifically, the lower end of the rubber cylinder center rod 230 is connected to the upper end of the connecting cylinder 210, and a third center channel 231 is provided at the axial position of the rubber cylinder center rod 230. The third center channel 231 is connected to the second center channel 221, and the accumulated fluid discharged from the second center channel 221 further enters the third center channel 231.

[0043] In addition, a first assembly groove is provided at the first end of the connecting tube 210. Specifically, the first assembly groove is provided at the upper end of the connecting tube 210. The lower end of the rubber tube center rod 230 is threadedly connected to the first assembly groove. Furthermore, a plurality of first sealing rings 232 are sleeved and provided on the outer side wall of the lower end of the rubber tube center rod 230. Specifically, two first sealing rings 232 are provided. The outer side walls of the first sealing rings 232 are in contact with the inner side wall of the connecting tube 210. The two first sealing rings 232 seal the gap at the threaded connection between the first assembly groove and the rubber tube center rod 230, effectively preventing accumulated fluid from leaking from the connection between the connecting tube 210 and the rubber tube center rod 230, thereby improving the sealing performance of the overall pumping and drainage plunger 200.

[0044] It should be noted that a sealing rubber sleeve 250 is sleeved onto the outer wall of the rubber sleeve center rod 230. During the initial stage of controlling the coiled tubing 400 to drive the pumping and drainage plunger 200 to ascend, when the liquid level within the annulus cavity 500 exceeds the liquid level within the gas well 100, the outer wall of the sealing rubber sleeve 250 abuts against the inner wall of the production tubing 300, thereby sealing the two ends of the pumping and drainage plunger 200. Preferably, the sealing rubber sleeve 250 is made of rubber with a certain wear resistance to ensure the service life of the entire pumping and drainage plunger 200.

[0045] In one embodiment of the present invention, the first end of the rubber sleeve center rod 230 is connected to the first joint 240. Specifically, the upper end of the rubber sleeve center rod 230 is threadedly connected to the first joint 240. The first joint 240 is connected to the coiled tubing 400 via a connector. A fourth central channel 241 is provided at the axial position of the first joint 240. The fourth central channel 241 is connected to the third central channel 231. The accumulated fluid discharged from the third central channel 231 further enters the fourth central channel 241, ensuring that the accumulated fluid ultimately enters the annulus cavity 500 at the upper end of the pumping and drainage plunger 200. Preferably, a plurality of second sealing rings 233 are sleeved on the outer wall of the upper end of the rubber sleeve center rod 230. The outer wall of the second sealing ring 233 contacts the inner wall of the first joint 240 to prevent the accumulated fluid in the annulus cavity 500 from leaking from the connection between the first joint 240 and the rubber sleeve center rod 230, thereby improving the sealing performance of the entire pumping and drainage plunger 200.

[0046] It should be noted that a number of pin holes are provided on the outer wall of the connecting cylinder 210, and the axial direction of the pin holes is consistent with the radial direction of the connecting cylinder 210. An annular groove is coaxially provided on the outer wall of the first end of the long-rod piston 220, and the shear pin 222 passes through the pin hole and is connected to the annular groove. The shear pin 222 is used to fix the long-rod piston 220 to the connecting cylinder 210 to limit the long-rod piston 220.

[0047] In one embodiment of the present invention, the rod-mounted piston 220 comprises an integrally formed piston portion and a rod portion, wherein an annular groove is provided on the outer wall of the piston portion, and the piston portion abuts against the pressure control spring 211. A plurality of third sealing rings 224 are sleeved on the outer wall of the upper end of the rod portion. The outer wall of the third sealing ring 224 abuts against the inner wall of the first central passage to prevent the accumulated fluid in the annular cavity 500 from leaking from the connection between the first central passage and the rod portion, further improving the sealing performance of the integral pumping and drainage plunger 200.

[0048] In addition, a positioning hole is provided on the outer wall of the long rod portion, and the positioning hole is connected to the pre-tightening pin 223. The pre-tightening pin 223 can reciprocate in the pressure relief channel 214 along the axial direction of the connecting cylinder 210 to limit the movement path of the long rod piston 220 in the axial direction of the connecting cylinder 210.

[0049] Furthermore, the first center channel is composed of two sections of a first limiting hole and a second limiting hole with different diameters. The first limiting hole is at the lower end of the first center channel, and the first limiting hole is adapted to the piston part. The second limiting hole is at the lower end of the first center channel, and the second limiting hole is adapted to the long rod part, and adapted to the piston 220 with a long rod. The diameter of the first limiting hole is larger than the diameter of the second limiting hole, thereby forming a certain limit on the piston 220 with a long rod. When the upper end surface of the piston 220 with a long rod is flush with the upper end surface of the first center channel, the top surface of the piston part abuts against the upper end surface of the second limiting hole, thereby ensuring that the long rod part will not enter the sealing cavity 212.

[0050] In one embodiment of the present invention, a second joint 260 is provided at the first end of the connecting tube 210. Specifically, a second assembly groove is provided at the lower end of the connecting tube 210, which is threadedly connected to the second joint 260. The end of the second joint 260 abuts the pressure control spring 211, and the pressure control spring 211 is fixed and limited by the second joint 260, wherein the second joint 260 is threadedly connected. In addition, a fifth central channel 261 is provided at the axial position of the second joint 260, extending therethrough. The fifth central channel 261 is connected to the first central channel, and the accumulated liquid in the gas well 100 first passes through the fifth central channel 261 before entering the first central channel.

[0051] In one embodiment of the present invention, a downhole tool string is installed at the inlet of coiled tubing 400. The downhole tool string includes a double-flap check valve (not shown), a hydraulic release mechanism (not shown), and a bypass valve (not shown). The double-flap check valve at the inlet of coiled tubing 400 primarily prevents fluid accumulated in the gas well 100 from entering the coiled tubing 400. The inlet of coiled tubing 400 is connected to the upper end of a swabbing and drainage plunger 200. The hydraulic release mechanism connects the upper and lower parts of the downhole tool string, primarily to separate them by applying hydraulic pressure in the event of a stuck condition. The bypass valve serves as a reserved circulation channel for cleaning the gas well 100. The entire downhole tool string ensures that operations such as cyclic well cleaning, blockage removal, unstuck removal, and release can be completed during operation.

[0052] The pumping and drainage method for the gas well 100 adopted in the present invention specifically includes the following steps: cleaning the inner wall of the gas well 100 and measuring the liquid level of the accumulated liquid in the gas well 100 to determine the insertion depth of the pumping and drainage plunger 200, connecting the continuous oil tubing 400 and the pumping and drainage plunger 200 and ensuring that the downhole tool string passes the pressure test, controlling the continuous oil tubing 400 and the downhole tool string to enter the gas well 100, and controlling the continuous oil tubing 400 to drive the pumping and drainage plunger 200 to move downward at a designed speed in the corresponding well section in the gas well 100 until the pumping and drainage plunger 200 is lowered to a preset position in the gas well 100 and the pumping and drainage plunger 200 is located in the accumulated liquid. After the pumping and drainage plunger 200 is at the preset position, the pressure at the second end of the pumping and drainage plunger 200 is greater than the pressure at the first end of the pumping and drainage plunger 200. The accumulated liquid in the gas well 100 passes through the first central channel and the second central channel 221 in sequence and enters the annular cavity 500. It remains stationary for 10-15 minutes. After the liquid level in the production tubing 300 reaches a certain amount, the coiled tubing 400 is controlled to drive the pumping and drainage plunger 200 to lift the coiled tubing 400 at the designed speed in the corresponding well section in the gas well 100. When the annular cavity After the liquid level of the accumulated liquid in the body 500 is higher than the liquid level of the accumulated liquid in the gas well 100, the sealing rubber sleeve 250 gradually begins to expand until the outer wall of the sealing rubber sleeve 250 fits with the inner wall of the production oil pipe 300, thereby sealing the two ends of the pumping and drainage plunger 200, until the pumping and drainage plunger 200 moves to the wellhead position of the gas well 100 and stays still for a certain period of time, such as 5 minutes, and a single pumping and drainage is completed. According to the drainage situation, the lowering depth of the pumping and drainage plunger 200 is increased to complete multiple pumping and drainage work until the gas well 100 resumes production.

[0053] It should be noted that the step of controlling the coiled tubing 400 to drive the pumping and drainage plunger 200 to elevate the coiled tubing 400 at the design speed in the corresponding well section further includes: when the pressure at the upper end of the pumping and drainage plunger 200 is greater than the pressure at the lower end of the pumping and drainage plunger 200, and the pressure difference between the upper end and the lower end of the pumping and drainage plunger 200 is greater than a first design value, the shear pin 222 is shortened by the shear force, and the piston 220 with the long rod loses its limit and slides a distance away from the first end of the first central channel under the action of pressure. The distance is such that the steel ball 213 is located at the pressure relief channel 214. At this time, the pressure relief channel 214 is connected to the first end of the first central channel, and a portion of the accumulated liquid in the annular cavity 500 is discharged into the gas well 100 through the first central channel, completing the pressure relief. When the pressure at the first end of the pumping and drainage plunger 200 drops to the second design value, the piston 220 with a long rod slides toward the first end of the first central channel under the support force of the pressure control spring 211 until the pressure relief channel 214 is no longer connected to the first central channel, thereby preventing the accumulated liquid in the annular cavity 500 from leaking further. It should be further noted that after a single pumping and drainage process is completed, the shear pin 222 that has been cut is replaced to ensure the stability of the next pumping and drainage process.

[0054] In summary, by providing the shear pins 222, when the pressure difference between the upper end of the pumping and drainage plunger 200 and the lower end of the pumping and drainage plunger 200 exceeds a first design value, the pressure relief channel 214 connects to the first end of the first central channel, allowing a portion of the accumulated liquid to be discharged into the gas well 100 through the first central channel, thereby achieving pressure relief and reducing the downward pull on the coiled tubing 400 and the pumping and drainage plunger 200, thereby protecting the coiled tubing 400, the downhole tool string, and the pumping and drainage plunger 200. Furthermore, when the pumping and drainage plunger 200 is lowered into the horizontal section of the gas well 100, the accumulated liquid in the horizontal section of the gas well 100 can still smoothly enter the annulus cavity 500, thereby accommodating the pumping and drainage of low-pressure gas wells 100 and ultra-deep horizontal gas wells 100, thereby ensuring that the gas energy in the gas well 100 can be fully collected and achieving a better pumping and drainage effect.

[0055] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0056] The principles and implementation methods of the present invention are described herein using specific examples. The description of the above examples is only intended to help understand the method and core concept of the present invention. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A gas well pumping and drainage device, characterized in that: include: Production tubing, used to transport chemical raw materials in the gas well and provide an operating space for the coiled tubing, with an annular cavity formed between the coiled tubing and the production tubing; A pumping and draining plunger is connected to the inlet end of the coiled tubing, and the pumping and draining plunger includes: A connecting cylinder, wherein a first central passage is provided at an axial position of the connecting cylinder, and a pressure control spring is provided at a second end of the first central passage; A piston with an extended rod, wherein the first end of the piston with an extended rod is inserted into the first central channel, the first end of the piston with an extended rod is fixedly connected to the connecting cylinder via a shear pin with a fixed shear value, the second end of the piston with an extended rod abuts against the pressure control spring, and a second central channel is provided at the axial position of the piston with an extended rod; A sealed cavity is provided at the first end of the connecting tube, and a steel ball is provided in the sealed cavity; The pressure relief channel is provided on the outer side wall of the connecting tube. When the steel ball is located at the position of the pressure relief channel, the pressure relief channel can be connected to the first end of the first central channel.

2. A gas well pumping and drainage device according to claim 1, characterized in that: The first end of the connecting cylinder is provided with a rubber cylinder center rod, the second end of the rubber cylinder center rod is connected to the first end of the connecting cylinder, and a third center channel is provided at the axial position of the rubber cylinder center rod, and the third center channel is connected to the second center channel.

3. A gas well pumping and drainage device according to claim 2, characterized in that: The first end of the connecting tube is provided with a first assembly groove, and the outer side wall of the second end of the center rod of the rubber tube is sleeved with a plurality of first sealing rings, and the outer side wall of the first sealing ring fits the first assembly groove.

4. A gas well pumping and drainage device according to claim 2, characterized in that: A sealing rubber sleeve is sleeved on the outer side wall of the rubber sleeve center rod. When the liquid level in the annular cavity is higher than the liquid level in the gas well, the outer side wall of the sealing rubber sleeve fits with the inner side wall of the production oil pipe.

5. A gas well pumping and drainage device according to claim 4, characterized in that: The first end of the rubber sleeve center rod is connected to the first joint, the first joint is connected to the coiled tubing through a connector, and a fourth center channel is provided at the axial position of the first joint, the fourth center channel is connected to the third center channel.

6. A gas well pumping and drainage device according to claim 1, characterized in that: The outer side wall of the connecting cylinder is provided with a plurality of pin holes, and the outer side wall of the first end of the long rod piston is coaxially provided with an annular groove, and the shear pin passes through the pin hole and is clamped to connect with the annular groove.

7. A gas well pumping and drainage device according to claim 1, characterized in that: The piston with a long rod includes: a piston part and a long rod part that are arranged in an integral manner, the piston part abuts the pressure control spring, and a positioning hole is provided on the outer wall of the long rod part. The positioning hole is connected to a pre-tightening pin, and the pre-tightening pin can reciprocate in the pressure relief channel along the axial direction of the connecting cylinder.

8. A gas well pumping and drainage device according to claim 1, characterized in that: A second joint is provided at the first end of the connecting tube, an end portion of the second joint abuts against the pressure control spring, and a fifth central channel is provided through the axial position of the second joint, the fifth central channel being connected to the first central channel.

9. A gas well pumping and drainage method, applied to the gas well pumping and drainage device according to any one of claims 1 to 8, characterized in that: The pumping and drainage method comprises: Controlling the coiled tubing to enter the gas well, and controlling the coiled tubing to drive the pumping and drainage plunger to move downward at a designed speed in a corresponding well section in the gas well; After the pumping and draining plunger is lowered to a preset position in the gas well and remains stationary for a certain period of time, the accumulated liquid in the gas well passes through the first central channel and the second central channel in sequence and enters the annular cavity; After the liquid level in the production tubing reaches a certain level, the coiled tubing is controlled to drive the pumping and drainage plunger to lift the coiled tubing at the designed speed in the corresponding well section of the gas well until the pumping and drainage plunger moves to the wellhead position of the gas well and remains stationary for a certain period of time, completing a single pumping and drainage operation.

10. A gas well pumping and drainage method according to claim 9, characterized in that: The step of controlling the coiled tubing to drive the pumping and drainage plunger to lift the coiled tubing at the designed speed in the corresponding well section also includes: When the pressure at the first end of the pumping and drainage plunger is greater than the pressure at the second end of the pumping and drainage plunger, and the pressure difference between the first end of the pumping and drainage plunger and the second end of the pumping and drainage plunger is greater than a first design value, the shear pin breaks, the piston with the long rod loses its limit and slides a distance away from the first end of the first central channel under the action of pressure until the steel ball is located at the position of the pressure relief channel. At this time, the pressure relief channel is connected to the first end of the first central channel, and a part of the accumulated liquid in the annular cavity is discharged into the gas well through the first central channel, thereby completing the pressure relief; When the pressure at the first end of the pumping and draining plunger drops to a second design value, the piston with a long rod slides toward the first end of the first center channel under the supporting force of the pressure control spring until the pressure relief channel is no longer connected to the first center channel, thereby preventing further leakage of the accumulated liquid in the annular cavity.

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