A sliding sleeve, integrated string, and method

Abstract

This invention proposes a switching sliding sleeve, an integrated tubing string, and a method, belonging to the technical field of sliding sleeve devices. The switching sliding sleeve includes an outer tool tube, and the outer tool tube and an inner tool tube are connected by a setting pin. The inner tool tube includes a sealing tube body, which is installed inside the outer tube. A sealing ring is provided in a groove on the outer wall of the sealing tube body, and a closing device is installed inside the sealing tube body, connected to the end of the sealing tube body away from the air inlet. The setting pin passes through the outer tube and connects to the sealing tube body. Natural energy drainage and gas extraction are achieved through the connection of the setting pin of the switching sliding sleeve through the outer tube and the sealing tube body. Alternatively, the closing device pushes the sealing tube body, causing the setting pin to shear under force, and the sealing tube body moves so that the two sets of sealing rings are located on both sides of the air inlet, completing the sealing of the air inlet and achieving mechanical drainage and gas extraction. Two drainage and gas extraction methods are achieved through one tubing string, effectively reducing the number of operations, reducing formation damage, and improving the quality and efficiency of coalbed methane production.

Description

Technical Field

[0001] This invention belongs to the technical field of sliding sleeve devices, and specifically relates to a switching sliding sleeve, an integrated tubular column, and a method therefor. Background Technology

[0002] Currently, coalbed methane (CBM) production mainly involves two stages, employing two sets of production tubing: In the initial stage, when formation production capacity is high, a flowing production tubing is installed. The CBM's self-flowing energy carries the bottom-hole fluid, and the fluid reaches the wellhead through the tubing, achieving natural energy-based fluid drainage and gas production. As oil and gas extraction progresses, the formation's natural energy gradually decreases, and the natural gas's fluid-carrying capacity becomes insufficient to remove all the bottom-hole fluid, leading to gradual fluid accumulation. Eventually, the natural energy-based fluid drainage and gas production model cannot meet the production demands. At this point, a mechanically operated fluid drainage and gas production tubing is installed. The pumping unit drives a downhole pump to extract the bottom-hole fluid from the tubing, reducing its impact on CBM production. CBM then flows through the annulus between the tubing and casing (hereinafter referred to as the annulus). These two sets of tubing require frequent switching, resulting in numerous operations, safety hazards, and potential formation damage from repeated operations.

[0003] A smart plunger-type drainage and gas extraction device, disclosed in CN104790917A, includes a pipe body containing: a control device comprising, from top to bottom, a pressure sensor, a control circuit board, and a battery pack, electrically connected in sequence; the pressure sensor being located below the inner wall of the pressure inlet; a valve device comprising, from top to bottom, a screw motor with a motor switch slider, and a switch sealing assembly with a switch sealing interface at the top; the sealing assembly having a gas-liquid channel running through it from top to bottom; a first gas-liquid port located between the switch sealing interface and the screw motor, and a second gas-liquid port located at the bottom of the pipe body; and a rubber sealing sleeve located below the first gas-liquid port and fitted onto the outer surface of the pipe body. The aforementioned device does not disclose the use of a switch slider on the pipe string to achieve switching between two types of pipe strings. Therefore, a device is needed that incorporates a switch slider on the pipe string. Summary of the Invention

[0004] To address the above problems, the present invention proposes a switch sleeve, comprising an outer tool tube, an inner tool tube disposed within the outer tool tube, and a closing device installed in the inner tool tube, wherein the outer tool tube and the inner tool tube are connected by a seat pin;

[0005] The tool outer tube includes an outer tube, and an air inlet is provided on the wall of the outer tube;

[0006] The inner tube of the tool includes a sealing tube body, which is installed inside the outer tube; a sealing ring is provided in a groove on the outer wall of the sealing tube body, there are at least two sets of sealing rings, and the distance between the two sets of sealing rings is greater than the diameter of the air inlet; a closing device is installed inside the sealing tube body, and the closing device is connected to the end of the sealing tube body away from the air inlet.

[0007] The setting pin passes through the outer tube and connects to the sealing tube body. The sealing tube body is misaligned with the air inlet.

[0008] The closing device pushes the sealing tube, the seat pin is sheared by force, the sealing tube moves to face the air inlet, and the two sets of sealing rings are on both sides of the air inlet.

[0009] Furthermore, the tool outer tube also includes a first connector, which is threadedly connected to one end of the outer tube.

[0010] Furthermore, a first positioning thread is provided on the inner side of the first connecting body, the inner diameter of the first positioning thread is smaller than the outer diameter of the sealing tube body, and the sealing tube body is located at the end of the first positioning thread near the outer tube.

[0011] Furthermore, the inner tube of the tool also includes a limiting column, which is threadedly connected to the end of the sealing tube away from the air inlet, and the limiting column is located inside the first connecting body.

[0012] Furthermore, a second positioning thread is provided on the outside of the limiting column, and the outer diameter of the second positioning thread is larger than the inner diameter of the first positioning thread.

[0013] Furthermore, the second positioning thread is located on the side of the first positioning thread away from the outer tube, or the second positioning thread engages with the first positioning thread.

[0014] Furthermore, the teeth of the first positioning thread are inclined towards the outer tube, and the teeth of the second positioning thread are inclined away from the outer tube, and the inclination angles of the teeth of the first positioning thread and the teeth of the second positioning thread are equal.

[0015] Furthermore, a second connector is threaded to the end of the first connector away from the outer tube, and the second connector is located at the end of the limiting tube away from the sealing tube.

[0016] Furthermore, the end of the outer tube furthest from the first connector is threaded with a first joint.

[0017] Furthermore, a step is provided on the inner side of the outer tube, and the step is located on the side of the sealing tube body close to the sealing ring.

[0018] An integrated draining and gas extraction tubing string includes a hydraulic unloader, which is connected to the first joint of the aforementioned switch sleeve, and the second joint of the switch sleeve is connected to the barrel of a tubular pump. The other end of the tubular pump barrel is connected to a gas anchor. The hydraulic unloader, switch sleeve, tubular pump barrel, and gas anchor are installed in a casing.

[0019] The tool inner tube of the switch sleeve is slidably installed with a second sucker rod, the aforementioned closing device, a first sucker rod, and a tubular pump plunger connected in sequence. The closing device is located at the end of the limiting tube column away from the sealing tube body. The end of the second sucker rod away from the closing device is connected to the ground drive equipment.

[0020] Furthermore, the closing device includes a detachably connected third connector and a switch claw. The third connector is slidably installed in the sealing tube or the limiting column, and the switch claw is slidably installed inside the second connector and located at the end of the limiting column away from the sealing tube.

[0021] Furthermore, the switch claw is provided with a sealing pin, which passes through the switch claw and is fixedly connected to the third connector.

[0022] Furthermore, the switch claw includes a sleeve connected to a third connector. A hook is provided at the end of the sleeve away from the third connector. The hook is located inside the second connector and at the end of the limiting tube away from the sealing tube.

[0023] Furthermore, the outer diameter of the hook is larger than the inner diameter of the limiting tube and smaller than the inner diameter of the second connector.

[0024] A method for draining and producing gas, using the aforementioned integrated draining and producing gas string, includes the following steps:

[0025] Underground pressure causes the oil-gas mixture to be separated by the gas anchor. The oil flows into the tubular pump barrel and the switch sleeve, while the natural gas enters the switch sleeve through the gas inlet and is discharged from the oil well through the hydraulic unloader.

[0026] The drive mechanism lifts the second sucker rod, which in turn drives the switch claw of the closing device to lift the inner tube of the tool until the sealing tube moves to the inside of the air inlet, sealing the air inlet and switching to mechanical pumping and gas extraction.

[0027] Furthermore, mechanically pumped liquid drainage and gas recovery includes the following steps:

[0028] The drive mechanism drives the tubular pump plunger to reciprocate within the tubular pump barrel, thereby extracting the accumulated oil from the tubular pump plunger and the switch sleeve to the wellhead, and extracting natural gas from the wellhead through the gap between the casing and the switch sleeve.

[0029] Furthermore, it also includes the following steps:

[0030] The drive mechanism moves the second sucker rod away from the gas anchor until the unsealing pin of the shut-off device is sheared, the third connector disengages from the switch claw, and the connected second sucker rod, third connector, and tubular pump plunger are removed to complete the removal of the tubing string.

[0031] Beneficial effects:

[0032] 1. This invention achieves natural energy drainage and gas extraction by connecting the setting pin of the switch sliding sleeve through the outer tube to the sealing tube body, or by closing the device and pushing the sealing tube body, causing the setting pin to shear under force, and the sealing tube body to move so that the two sets of sealing rings are located on both sides of the gas inlet, thus sealing the gas inlet and realizing mechanical drainage and gas extraction. Two drainage and gas extraction methods are achieved through one set of tubing, effectively reducing the number of operations, reducing formation damage, and improving the quality and efficiency of coalbed methane production.

[0033] 2. The present invention provides a first positioning thread on the inner side of the first connector body and a second positioning thread on the outer side of the limiting column. The engagement of the first positioning thread and the second positioning thread causes the limiting column to be forced to move towards the air inlet, while preventing the limiting column from moving away from the first connector, thereby determining that the limiting column moves in one direction.

[0034] 3. This invention achieves oil and gas extraction by lowering a series of interconnected air anchors, tubular pump barrels, switch sleeves, and hydraulic unloaders into the casing, and switches between two modes via the switch sleeve.

[0035] 4. This invention includes a closing device comprising a detachably connected third connector and a switch claw. The third connector and the switch claw are connected by a release pin, or the release pin is sheared off under force, separating the switch claw and the third connector. This facilitates the switch claw driving the limiting column, thereby causing the inner tube of the tool to move upward.

[0036] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic diagram of the switch sleeve in Embodiment 1 of the present invention is shown.

[0039] Figure 2 A schematic diagram of the structure of the integrated tubular column in Embodiment 2 of the present invention is shown.

[0040] Figure 3 A schematic diagram of the closing device according to Embodiment 2 of the present invention is shown.

[0041] Figure 4 A schematic diagram of the structure of the switching claw in Embodiment 2 of the present invention is shown.

[0042] Figure 5 A schematic diagram of the liquid drainage and gas extraction method in Embodiment 3 of the present invention is shown.

[0043] In the diagram, 1. Gas anchor; 2. Tube pump barrel; 3. Tube pump plunger; 6. Hydraulic unloader; 7. First sucker rod; 8. Second sucker rod; 9. Casing; 10. Oil well; 11. Tubing;

[0044] 4. Closing device; 401. Third connector; 402. Unsealing pin; 403. Switch claw; 4031. Sleeve; 4032. Groove; 4033. Hook;

[0045] 5. Switch sleeve; 501. First connector; 502. Outer tube; 503. Sealing ring; 504. Sealing pin; 505. Sealing tube body; 506. First connector; 5061. First positioning thread; 507. Limiting column; 5071. Second positioning thread; 508. Second connector; 509. Air inlet; 510. Step. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1,

[0048] like Figure 1 As shown, Figure 1 A schematic diagram of the switch sliding sleeve in an embodiment of the present invention is shown. (Reference) Figure 1 A switch sleeve includes an outer tool tube, an inner tool tube disposed inside the outer tool tube, and a closing device 4 installed in the inner tool tube. The outer tool tube and the inner tool tube are connected by a setting pin 504; they remain relatively stationary; under sufficient shear pressure, the setting pin 504 can be sheared, at which point the outer tool tube and the inner tool tube can move relative to each other.

[0049] Specifically, the tool outer tube includes an outer tube 502, with an air inlet 509 on its wall; the tool inner tube includes a sealing tube body 505, which is installed inside the outer tube 502; a sealing ring 503 is provided in a groove on the outer wall of the sealing tube body 505, with at least two sets of sealing rings 503, and the distance between the two sets of sealing rings 503 is greater than the diameter of the air inlet 509; a closing device 4 is installed inside the sealing tube body 505, and the closing device 4 is connected to the end of the sealing tube body 505 away from the air inlet 509; a setting pin 504 passes through the outer tube 502 and connects to the sealing tube body 505, with the sealing tube body 505 misaligned with or not misaligned with the air inlet 509.

[0050] The closing device 4 pushes the sealing tube 505, the seat pin 504 is sheared by force, the sealing tube 505 moves to face the air inlet 509, and the two sets of sealing rings 503 are on both sides of the air inlet 509.

[0051] The present invention has two states: when the sealing tube 505 is fixed by the seat pin 504, gas can enter the outer tube 502 through the air inlet 509; when the sealing tube 505 is moved by force and seals the air inlet 509, the air inlet 509 is sealed.

[0052] In this invention, the outer tube of the tool further includes a first connecting body 506, which is threadedly connected to one end of the outer tube 502. A first positioning thread 5061 is provided on the inner side of the first connecting body 506. The inner diameter of the first positioning thread 5061 is smaller than the outer diameter of the sealing tube 505, and the sealing tube 505 is located at the end of the first positioning thread 5061 near the outer tube 502. The first positioning thread 5061 is used to limit the sealing tube 505. The inner tube of the tool further includes a limiting post 507, which is threadedly connected to the end of the sealing tube 505 away from the air inlet 509. The limiting post 507 is located inside the first connecting body 506.

[0053] Furthermore, a second positioning thread 5071 is provided on the outside of the limiting column 507, and the outer diameter of the second positioning thread 5071 is larger than the inner diameter of the first positioning thread 5061. The second positioning thread 5071 engages with the first positioning thread 5061 to limit the limiting column 507. The second positioning thread 5071 is located on the side of the first positioning thread 5061 away from the outer tube 502, or the second positioning thread 5071 engages with the first positioning thread 5061. When the setting pin 504 passes through the outer tube 502 and connects to the sealing tube body 505, the second positioning thread 5071 is located on the side of the first positioning thread 5061 away from the outer tube 502. When the setting pin 504 is sheared by force, the sealing tube body 505 moves so that the two sets of sealing rings 503 are located on both sides of the air inlet 509, and the second positioning thread 5071 engages with the first positioning thread 5061.

[0054] In the above embodiments, another optional implementation is that the teeth of the first positioning thread 5061 are inclined towards the outer tube 502, and the teeth of the second positioning thread 5071 are inclined away from the outer tube 502, and the inclination angles of the teeth of the first positioning thread 5061 and the second positioning thread 5071 are equal. This facilitates the movement of the limiting column 507 towards the air inlet 509 under force, while preventing the limiting column 507 from moving away from the first connector 501. This design ensures that when the inner tube of the tool is forcefully lifted, the setting pin 504 is sheared, and the inner tube of the tool moves upward relative to the outer tube of the tool (see reference). Figure 2 The sealing ring 503 is positioned on both sides of the air inlet 509 to ensure a complete seal of the air inlet 509. After the lifting force is removed, the outer tube of the tool will not move downward relative to the inner tube of the tool under the action of the first positioning thread 5061 and the second positioning thread 5071, and the air inlet 509 will not fail to seal due to the removal of the lifting force.

[0055] Furthermore, a second connector 508 is threadedly connected to the end of the first connector 506 away from the outer tube 502. The second connector 508 is located at the end of the limiting tube 507 away from the sealing tube 505. The second connector 508 is connected to the tubular pump barrel 2 via the oil pipe 11. A first connector 501 is threadedly connected to the end of the outer tube 502 away from the first connector 506. The first connector 501 is connected to the hydraulic unloader 6 via the oil pipe 11.

[0056] Specifically, a step 510 is provided inside the outer tube 502. The step 510 is located on the side of the air inlet 509 near the first connector 501 (the step 510 is located on the side of the sealing tube 505 near the sealing ring 503). The step 510 is used to limit the movement distance of the sealing tube 505 to prevent the sealing tube 505 from being too far away, which would cause the air inlet 509 to be not between the two sealing rings 503 and reduce the sealing effect.

[0057] Working principle: During use, the second connector 508 is connected to the tubular pump barrel 2 via the oil pipe 11, and the first connector 501 is connected to the hydraulic unloader 6 via the oil pipe 11. In the initial state, when the sealing tube body 505 is fixed by the seat pin 504, gas can enter the outer tube 502 through the air inlet 509. When the sealing tube body 505 is subjected to force and moves towards the first connector 501, since the first positioning thread 5061 and the second positioning thread 5071 are both inclined and in opposite directions, it is convenient for the second positioning thread 5071 to move towards the first connector 501. However, the second positioning thread 5071 is stuck by the first positioning thread 5061 and cannot move towards the second connector 508. Therefore, the sealing tube body 505 is prevented from moving towards the second connector 508, preventing the seal from failing. When the sealing tube body 505 moves to contact the step 510, the two sealing rings 503 are located on both sides of the air inlet 509, thereby achieving a seal.

[0058] Example 2,

[0059] like Figure 2 As shown, Figure 2 A schematic diagram of the integrated tubular column structure in an embodiment of the present invention is shown. (Reference) Figure 2 An integrated drainage and gas production tubing string includes a gas anchor 1, a tubular pump barrel 2, a switch sleeve (as described in Example 1), and a hydraulic unloader 6 connected in sequence. Specifically, the hydraulic unloader 6 is connected to the first connector 501 of the switch sleeve 5, the second connector 508 of the switch sleeve 5 is connected to the tubular pump barrel 2, and the other end of the tubular pump barrel 2 is connected to the gas anchor 1. The hydraulic unloader 6, switch sleeve 5, tubular pump barrel 2, and gas anchor 1 are installed in a casing 9. A second sucker rod 8, a closing device 4, a first sucker rod 7, and a tubular pump plunger 3 are slidably installed in the tool inner tube of the switch sleeve 5. The closing device 4 is located at the end of the limiting tubing 507 away from the sealing tube 505. The end of the second sucker rod 8 away from the closing device 4 is connected to the surface drive equipment. The gas anchor 1, tubular pump barrel 2, switch sleeve 5, and hydraulic unloader 6 connected in series are then lowered into the casing 9, and the casing 9 is installed in the oil well 10.

[0060] refer to Figure 3 The closing device 4 includes a detachably connected third connector 401 and a switch claw 403. The third connector 401 and the switch claw 403 are connected by a release pin 402, or the release pin 402 is sheared by force, separating the switch claw 403 from the third connector 401. The switch claw 403 is provided with a release pin 402, which passes through the switch claw 403 and is fixedly connected to the third connector 401. The third connector 401 is slidably installed in the sealing tube 505 or the limiting tube 507, and the switch claw 403 is slidably installed inside the second connector 508 and located at the end of the limiting tube 507 away from the sealing tube 505.

[0061] refer to Figure 4 The switch claw 403 includes a sleeve 4031, which is connected to the third connector 401. A hook 4033 is provided at the end of the sleeve 4031 away from the third connector 401. A groove 4032 is provided between adjacent hooks 4033, such as... Figure 4 As shown, the present invention is provided with six hooks 4033 arranged in a circumferential array. The hooks 4033 are located inside the second connector 508 and at the end of the limiting tube 507 away from the sealing tube 505. The outer diameter of the hooks 4033 is larger than the inner diameter of the limiting tube 507 and smaller than the inner diameter of the second connector 508. When the hooks 4033 are lifted, they engage the limiting tube 507, thereby causing the inner tube of the tool to move upward.

[0062] Example 3,

[0063] like Figure 5 As shown, a method for draining and gasifying gas, using the integrated draining and gasifying gasifying tubing of Example 2 above, includes the following steps:

[0064] Underground pressure causes the oil-gas mixture to separate through the gas anchor 1. The oil flows into the tubular pump cylinder 2 and the switch sleeve 5, while the natural gas enters the switch sleeve 5 through the gas inlet 509 and is discharged from the oil well 10 through the hydraulic unloader 6.

[0065] The drive mechanism lifts the second sucker rod 8, which in turn drives the switch claw 403 of the closing device 4 to lift the inner tube of the tool until the sealing tube 505 moves to the inside of the air inlet 509, sealing the air inlet 509 and switching to mechanical pumping and gas extraction.

[0066] Specifically, mechanically pumped liquid drainage and gas recovery includes the following steps:

[0067] The drive mechanism drives the tubular pump plunger 3 to reciprocate in the tubular pump barrel 2, thereby extracting the accumulated oil in the tubular pump plunger 3 and the switch sleeve 5 to the wellhead, and the natural gas is extracted from the wellhead through the gap between the casing 9 and the switch sleeve 5.

[0068] Specifically, removing the tubing also includes the following steps:

[0069] The drive mechanism moves the second sucker rod 8 away from the gas anchor 1 until the unsealing pin 402 of the closing device 4 is cut off and the third connector 401 is disengaged from the switch claw 403. Then, the connected second sucker rod 8, third connector 401 and tubular pump plunger 3 are removed in sequence to complete the removal of the tubing.

[0070] Overall workflow:

[0071] First, casing 9 is installed in oil well 10, and gas anchor 1, tubular pump barrel 2, switch sleeve 5 and hydraulic unloader 6 are installed in casing 9 in sequence; tubular pump plunger 3 and shut-off device 4 connected by first sucker rod 7 are installed in switch sleeve 5, with shut-off device 4 located between switch sleeve 5 and tubular pump barrel 2; at this time, oil is introduced into switch sleeve 5 through tubular pump barrel 2 by underground pressure, and then natural gas is discharged from oil well 10 through gas inlet 509 and switch sleeve 5;

[0072] When switching to mechanical pumping and gas extraction mode, the second sucker rod 8 is lifted, causing the switch claw 403 of the closing device 4 to contact the limiting string 507 of the switch sleeve 5. Continuing to lift the second sucker rod 8 moves the sealing pipe 505 to the inside of the air inlet 509 until it stops moving; at this point, the air inlet 509 of the switch sleeve 5 is sealed. Then, the second sucker rod 8 is connected above the wellhead of the oil well 10, and connected to the surface drive mechanism. The surface drive mechanism lowers the tubular pump plunger 3 into the tubular pump barrel 2. At this point, the pumping and gas extraction mode is switched to mechanical pumping and gas extraction mode. The surface drive mechanism drives the tubular pump plunger 3 to reciprocate within the tubular pump barrel 2, thus extracting the accumulated liquid in the wellbore through the tubing 11 to the wellhead, and extracting natural gas through the gap between the casing 9 and the switch sleeve 5 to the wellhead. The tubular pump barrel 2 and the tubular pump plunger 3 constitute the pumping pump.

[0073] When the tubing string needs to be removed, pull the second sucker rod 8 upwards forcefully until the unsealing pin 402 of the shut-off device 4 is sheared, the third connector 401 disengages from the switch claw 403, and the switch claw 403 remains inside the switch sleeve 5. Then, remove the connected second sucker rod 8, third connector 401, and tubular pump plunger 3 in sequence.

[0074] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A switch sliding sleeve, characterized in that, It includes an outer tool tube, an inner tool tube disposed within the outer tool tube, and a closing device (4) installed in the inner tool tube. The outer tool tube and the inner tool tube are connected by a setter pin (504). The tool outer tube includes an outer tube (502), and an air inlet (509) is provided on the wall of the outer tube (502); The inner tube of the tool includes a sealing tube body (505), which is installed inside the outer tube (502); a sealing ring (503) is provided in a groove on the outer wall of the sealing tube body (505), and there are at least two sets of sealing rings (503), and the distance between the two sets of sealing rings (503) is greater than the diameter of the air inlet (509); a closing device (4) is installed inside the sealing tube body (505), and the closing device (4) is connected to the end of the sealing tube body (505) away from the air inlet (509); The setting pin (504) passes through the outer tube (502) and connects to the sealing tube body (505). The sealing tube body (505) is misaligned with the air inlet (509). The closing device (4) pushes the sealing tube (505), the seat pin (504) is sheared by force, the sealing tube (505) moves to face the air inlet (509), and the two sets of sealing rings (503) are on both sides of the air inlet (509).

2. The switch sliding sleeve according to claim 1, characterized in that, The tool outer tube also includes a first connector (506), which is threaded to one end of the outer tube (502).

3. A switch sleeve according to claim 2, characterized in that, The first connector (506) has a first positioning thread (5061) on its inner side. The inner diameter of the first positioning thread (5061) is smaller than the outer diameter of the sealing tube (505). The sealing tube (505) is located at the end of the first positioning thread (5061) near the outer tube (502).

4. A switch sleeve according to claim 3, characterized in that, The inner tube of the tool also includes a limiting column (507), which is threadedly connected to the end of the sealing tube (505) away from the air inlet (509), and the limiting column (507) is located inside the first connecting body (506).

5. A switch sleeve according to claim 4, characterized in that, A second positioning thread (5071) is provided on the outside of the limiting column (507), and the outer diameter of the second positioning thread (5071) is larger than the inner diameter of the first positioning thread (5061).

6. A switch sliding sleeve according to claim 5, characterized in that, The second positioning thread (5071) is located on the side of the first positioning thread (5061) away from the outer tube (502) or the second positioning thread (5071) engages with the first positioning thread (5061).

7. A switch sleeve according to claim 5 or 6, characterized in that, The teeth of the first positioning thread (5061) are inclined toward the outer tube (502), and the teeth of the second positioning thread (5071) are inclined away from the outer tube (502), and the inclination angles of the teeth of the first positioning thread (5061) and the teeth of the second positioning thread (5071) are equal.

8. A switch sleeve according to claim 2, characterized in that, The first connector (506) is threaded to a second connector (508) at the end away from the outer tube (502). The second connector (508) is located at the end of the limiting tube (507) away from the sealing tube (505).

9. A switch sleeve according to claim 1, characterized in that, The outer tube (502) is threaded to the end away from the first connector (506) with a first joint (501).

10. A switch sleeve according to claim 1, characterized in that, The outer tube (502) has a step (510) on its inner side, and the step (510) is located on the side of the sealing tube body (505) near the sealing ring (503).

11. An integrated drainage and gas production tubing string, characterized in that, The system includes a hydraulic unloader (6), which is connected to the first connector (501) of the switch sleeve (5) according to any one of claims 1-10, and the second connector (508) of the switch sleeve (5) is connected to the tubular pump barrel (2), the other end of which is connected to the air anchor (1); the hydraulic unloader (6), the switch sleeve (5), the tubular pump barrel (2) and the air anchor (1) are installed in the sleeve (9); The switch sleeve (5) is slidably installed in the tool inner tube with a second sucker rod (8), a closing device (4) as described in any one of claims 1-10, a first sucker rod (7), and a tubular pump plunger (3) connected in sequence. The closing device (4) is located at the end of the limiting tube string (507) away from the sealing tube body (505). The end of the second sucker rod (8) away from the closing device (4) is connected to the ground drive equipment.

12. The integrated drainage and gas production tubing string according to claim 11, characterized in that, The closing device (4) includes a detachably connected third connector (401) and a switch claw (403). The third connector (401) is slidably installed in the sealing tube (505) or the limiting tube (507). The switch claw (403) is slidably installed inside the second connector (508) and located at the end of the limiting tube (507) away from the sealing tube (505).

13. The integrated drainage and gas production tubing string according to claim 12, characterized in that, The switch claw (403) is provided with a sealing pin (402), which passes through the switch claw (403) and is fixedly connected to the third connector (401).

14. The integrated drainage and gas production tubing string according to claim 12, characterized in that, The switch claw (403) includes a sleeve (4031) connected to the third connector (401). A hook (4033) is provided at the end of the sleeve (4031) away from the third connector (401). The hook (4033) is located inside the second connector (508) and at the end of the limiting column (507) away from the sealing tube (505).

15. The integrated drainage and gas production tubing string according to claim 14, characterized in that, The outer diameter of the hook (4033) is greater than the inner diameter of the limiting column (507) and less than the inner diameter of the second connector (508).

16. A method for draining liquid and collecting gas, characterized in that, The integrated drainage and gas production string according to any one of claims 11-15 includes the following steps: Underground pressure causes the oil-gas mixture to separate through the gas anchor (1). The oil flows into the tubular pump barrel (2) and the switch sleeve (5), while the natural gas enters the switch sleeve (5) through the gas inlet (509) and is discharged from the oil well (10) through the hydraulic unloader (6). The drive mechanism lifts the second sucker rod (8), which drives the switch claw (403) of the closing device (4) to lift the inner tube of the tool until the sealing tube (505) moves to the inside of the air inlet (509), the air inlet (509) is sealed, and the machine-operated drainage and gas extraction is switched.

17. A method for draining liquid and collecting gas according to claim 16, characterized in that, Mechanically pumped gas recovery includes the following steps: The drive mechanism drives the tubular pump plunger (3) to reciprocate in the tubular pump barrel (2), thereby extracting the accumulated oil in the tubular pump plunger (3) and the switch sleeve (5) to the wellhead, and the natural gas is extracted from the wellhead through the gap between the casing (9) and the switch sleeve (5).

18. A method for draining liquid and collecting gas according to claim 16, characterized in that, It also includes the following steps: The drive mechanism moves the second sucker rod (8) away from the gas anchor (1) until the unsealing pin (402) of the closing device (4) is cut off, the third connector (401) is disengaged from the switch claw (403), and the connected second sucker rod (8), third connector (401) and tubular pump plunger (3) are removed to complete the removal of the tubing.

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