A large-diameter removable gas well anchoring and sealing device

Abstract

The present invention belongs to the technical field of oil production tools, and particularly relates to a large-diameter removable gas well anchoring and sealing device, the sealing device comprising an upper joint (1) and a central tube (2), wherein the inner wall of the lower end of the upper joint (1) is threadedly connected to the central tube (2), the outer wall of the lower end of the upper joint (1) is connected to an upper cone (5) via an unsealing shear nail (3), and the lower end of the central tube (2) is threadedly connected to a limiting nut (29) and a lower joint (28) in sequence. The slips of the present invention are completely unsealed, will not cause accidents due to jamming, and have a reliable sealing effect.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production tools, and in particular relates to a large-diameter removable gas well anchoring and isolation device. Background Art

[0002] With increasing attention paid to environmental protection at home and abroad, carbon dioxide flooding, as a typical green and environmentally friendly technology, can not only solve the problem of greenhouse gas emission reduction, but also improve the crude oil recovery rate of old oil fields. However, the resulting high-temperature and high-pressure carbon dioxide corrosion problem on the wellbore cannot be ignored. At present, most domestic carbon dioxide injection wells use foreign retrievable packers and permanent packers. However, due to structural limitations, retrievable packers mostly have problems such as small internal diameter, poor sealing effect and difficulty in unsealing. Although permanent packers have good sealing effect, they still have problems such as difficult handling and recovery when encountering obstructions in the middle of the process. Summary of the Invention

[0003] In order to solve the problems existing in carbon dioxide oil recovery, the present invention provides a large-diameter removable gas well anchoring and sealing device. The slips of the present invention can be completely unsealed without causing accidents due to sticking, and the sealing effect is reliable.

[0004] The technical problem solved by the present invention is achieved by adopting the following technical solutions:

[0005] The large-diameter removable gas well anchoring and isolation device comprises an upper joint and a center pipe, the inner wall of the lower end of the upper joint is threadedly connected to the center pipe, the outer wall of the lower end of the upper joint is connected to the upper cone by an unsealing shear nail, the outer side of the lower part of the upper cone is provided with a cone surface, the upper cone is sleeved on the outer wall of the center pipe, the outer wall of the center pipe is also sleeved with an unblocking sleeve, the upper part of the unblocking sleeve is located in the annular cavity between the upper cone sleeve and the center pipe, the middle inner wall of the unblocking sleeve and the outer wall of the center pipe corresponding to the middle of the unblocking sleeve are provided with an annular groove, and a one-way locking spring is installed in the annular groove, and a locking ring groove is provided on the outer wall of the center pipe corresponding to the lower end face of the unblocking sleeve, and a locking ring is installed in the locking ring groove. The limit lock ring of the opening, a part of the limit lock ring is located in the lock ring groove, and the other part of the limit lock ring is located at the lower end surface of the unlocking sleeve, and the unlocking sleeve is aligned with the end surface of the limit lock ring; the lower end of the unlocking sleeve is sleeved with a lower cone, and the outer side of the upper part of the lower cone is provided with a cone surface, the upper inner wall of the lower cone is provided with a lock groove and a one-way lock spring 2 is installed in the lock groove, and the lock spring 2 cooperates with the threaded teeth on the outer wall of the lower end of the unlocking sleeve, and the middle part of the unlocking sleeve is sleeved with a slip, the cone surface of the upper end of the slip is pressed on the cone surface of the upper cone, and the cone surface of the lower end of the slip is pressed on the cone surface of the lower cone, and a spring is installed in the hole of the outer wall of the middle part of the slip, and the outer cover of the slip is provided with a spring. The cam is provided with a screw thread, and the screw thread is connected to the screw thread of the upper end of the cam, and the screw thread is connected to the screw thread of the lower end of the cam, and the screw thread is connected to the screw thread of the lower end of the cam. The cam is connected to the cam frame by means of a screw thread, and the cam frame is connected to the cam frame by means of a screw thread.

[0006] The upper outer wall of the unlocking sleeve is provided with three evenly distributed key slots, and the inner wall of the upper cone is provided with an annular groove on the surface corresponding to the unlocking sleeve. The key slot on the unlocking sleeve corresponds to the annular groove on the upper cone and a soluble locking block is provided in the groove.

[0007] An inner sealing ring is installed between the upper portion of the unlocking sleeve and the central tube, and an outer sealing ring is installed between the upper portion of the unlocking sleeve and the upper cone.

[0008] The soluble locking block expands outward to the inner diameter ring groove of the upper cone under the support of the center tube step, locks the upper cone and the unlocking sleeve into one, and pushes down until the lower end face of the unlocking sleeve is aligned with the upper end face of the limit lock ring.

[0009] The beneficial effects of the present invention are as follows: 1. The slip is located above the rubber cylinder, and the injected carbon dioxide is isolated from the anchoring device above, to prevent the anchoring device from being corroded or the contact part of the slip with the casing from being corroded, causing the casing to be damaged, losing the anchoring effect or causing an accident when the pipe string is recovered; 2. One-way locking springs are designed inside and outside the unlocking sleeve to prevent the rubber cylinder from being recovered after unsealing or incompletely recovered when lifting the pipe, and the downward pressure pushes the rubber cylinder and the lower cone upward, causing the slip to not be recovered; 3. The soluble locking block mechanism is designed. Before the unsealing shear nails are cut off, the soluble locking block is in a closed cavity and does not contact the well fluid. After the unsealing shear nails are cut off, the soluble locking block loses its seal and contacts the well fluid, and it will completely dissolve in 3-5 days. The upper cone and the unlocking sleeve lose their lock and are completely separated, and the slip is completely unsealed; 4. The sealing mechanism and the unlocking mechanism are designed with an anti-obstruction mechanism to ensure that they can operate correctly when encountering obstructions; 5. The double-stage sealing mechanism is designed to increase the sealing force, ensure that the rubber cylinder is sealed tightly and can withstand high pressure, and improve the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the present invention;

[0011] Figure 2 yes Figure 1 Cross-section at AA;

[0012] Figure 3 yes Figure 1 Cross-section at the middle BB;

[0013] Figure 4 yes Figure 1 Cross-section at CC;

[0014] In the figure: 1, upper joint, 2, center tube, 3, unsealing shear pin, 4, slip cover cap, 5, upper cone, 6, slip cover, 7, unsealing sleeve, 8, slip, 9, lock spring one, 10, spring, 11, lock spring two, 12, limit lock ring, 13, lower cone, 14, rubber cylinder shaft, 15, rubber cylinder assembly, 16, lower pressure ring, 17, lock spring seat, 18, lock spring three, 19, setting sealing sleeve, 20, upper setting piston, 21, split nut, 22, upper cylinder, 23, card block, 24, setting shear pin, 25, lower cylinder, 26, lower setting piston, 27, guide cap, 28, lower joint, 29, limit nut, 30, soluble lock block, 31, inner sealing ring, 32, outer sealing ring. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the accompanying drawings:

[0016] The outer wall of the lower end of the upper joint 1 is connected to the upper cone 5 by an unsealing shear nail 3. The outer side of the lower part of the upper cone 5 is provided with a conical surface. The upper cone 5 is sleeved on the outer wall of the central tube 2. The outer wall of the central tube 2 is also sleeved with an unblocking sleeve 7. The upper part of the unblocking sleeve 7 is located in the annular cavity between the upper cone 5 and the central tube 2. The inner wall of the middle part of the unblocking sleeve 7 and the outer wall of the central tube 2 corresponding to the middle part of the unblocking sleeve 7 are provided with an annular groove and a one-way locking spring 9 is installed in the annular groove. The one-way locking spring 9 locks the unblocking sleeve 7 on the central tube 2. The unblocking sleeve 7 can only move downward relative to the central tube 2 under the action of the locking spring 9. The outer wall of the central tube 2 corresponding to the lower end face of the unblocking sleeve 7 is provided with an There is a locking ring groove and an open limiting locking ring 12 is installed in the locking ring groove, a part of the limiting locking ring 12 is located in the locking ring groove, and the other part of the limiting locking ring 12 is located at the lower end face of the unlocking sleeve 7, and the unlocking sleeve 7 is aligned with the end face of the limiting locking ring 12; the lower end of the unlocking sleeve 7 is sleeved with a lower cone 13, and the outer side of the upper part of the lower cone 13 is provided with a conical surface, the upper inner wall of the lower cone 13 is provided with a locking groove and a one-way locking spring 2 11 is installed in the lock groove, and the locking spring 2 11 cooperates with the threaded teeth on the outer wall of the lower end of the unlocking sleeve 7, and the locking spring 2 11 locks the lower cone 13 on the unlocking sleeve 7, and the middle part of the unlocking sleeve 7 is sleeved with a slip 8, the conical surface of the upper end of the slip 8 presses on the conical surface of the upper cone 5, and the conical surface of the lower end of the slip 8 presses on the conical surface of the lower cone 13, and a spring 1 is installed in the hole of the outer wall of the middle part of the slip 8 0, the outer cover of the slip cover 8 is provided with a slip cover 6, and the slip cover 6 is provided with a window. The upper end of the slip cover 6 is threadedly connected with the slip cover cap 4, and the slip cover cap 4 is sleeved on the shoulder of the outer wall of the upper cone 5, and the lower end of the slip cover 6 is clamped with the lower cone 13; the lower end of the lower cone 13 is threadedly connected to the rubber cylinder shaft 14, and the outer wall of the rubber cylinder shaft 14 is sequentially sleeved with the rubber cylinder assembly 15 and the lower pressure ring 16; the lower end of the rubber cylinder shaft 14 is threadedly connected to the lock spring seat 17, and the outer wall of the lower end of the lock spring seat 17 is installed with a one-way lock spring three 18, and the outer wall of the lower end of the lock spring seat 17 is sleeved with a seat sealing sleeve 19, and the lock spring three 18 cooperates with the threaded teeth on the inner wall of the seat sealing sleeve 19. The lock spring seat 17 and the seat sealing sleeve 19 are unidirectionally locked by the lock spring three 18, and the seat sealing sleeve 19 is threadedly connected to the lower pressure ring 16, and the lower end surface of the seat sealing sleeve 19 is provided with The upper sealing piston 20 is provided with a split nut 21 on the inner wall of the lower end of the upper sealing piston 20, and the split nut 21 is internally threadedly connected to the center tube 2. The outer wall of the lower end of the sealing sleeve 19 is threadedly connected to the upper end of the cylinder 22. A clamping block 23 is installed in the groove at the lower end of the connecting cylinder 22, and the inner wall of the clamping block 23 is located in the annular groove of the center tube 2. The lower end of the center tube 2 is threadedly connected to the limiting nut 29 and the lower joint (28) in sequence. The upper wall of the limiting nut 29 and the upper part of the lower joint 28 is provided with a lower sealing piston 26. The lower sealing piston (26) is connected to the upper cylinder 22 by a sealing shear pin 24. At the same time, the lower sealing piston 26 presses the clamping block 23. The lower end of the upper cylinder 22 is threadedly connected to the lower cylinder 25. The outer wall of the lower joint 28 is threadedly connected to the guide cap 27, and the guide cap 27 is clamped with the lower cylinder 25.

[0017] The upper outer wall of the unlocking sleeve 7 is provided with 3 evenly distributed key slots such as Figure 4 As shown, an annular groove is opened on the inner wall of the upper cone 5 corresponding to the unlocking sleeve 7, the key groove on the unlocking sleeve 7 corresponds to the annular groove on the upper cone 5 and a soluble locking block 30 is provided in the groove.

[0018] An inner sealing ring 31 is installed between the upper portion of the unlocking sleeve 7 and the central pipe 2, and an outer sealing ring 32 is installed between the upper portion of the unlocking sleeve 7 and the upper cone 5. A sealing rubber ring is provided to seal the soluble lock block 30 from contacting the well fluid.

[0019] Key points of this application's design:

[0020] 1. When unsealing, the lower cone 13 is designed with an anti-upward mechanism; a one-way locking spring 9 is set in the unlocking sleeve 7 to lock it on the central pipe 2, and a one-way locking spring 2 11 is set outside the unlocking sleeve 7 to lock it with the lower cone 13. The action process is: when the large-diameter removable gas well anchoring and isolation device is set, the lower cone 13 moves upward and is locked with the unlocking sleeve 7 in one direction at the same time, and the slips 8 expand outward to form an anchor with the casing. At this time, the outside of the limiting lock ring 12 is at the large-diameter position of the lower cone 13, and the external pressure limit of the lower cone 13 is lost. When unsealing, the pipe string is lifted, the upper joint 1 and the central pipe 2 move upward, the limiting lock ring 12 loses the limit of the lower cone 13 and expands outward, cutting the unsealing shear nail 3, and the upper boss of the central pipe 2 moves upward to the step of the upper cone 5, and the unlocking sleeve is unlocked. The soluble locking block 30 in 7 loses the support of the central tube 2 and can be recovered. The unlocking sleeve 7 and the upper cone 5 lose the fixation of the soluble locking block 30 and separate. The upper cone 5 moves upward by the slip 8 to be recovered. At the same time, the lower cone 13 is locked to the outside of the unlocking sleeve 7 by the one-way locking spring 11, which is equivalent to a whole. The unlocking sleeve 7 can only move downward relative to the central tube 2 under the action of the locking spring 9. At this time, the rubber cylinder assembly 15 has not been recovered. Under the action of downward pressure, the rubber cylinder assembly 15, the rubber cylinder shaft 14, and the lower cone 13 have an upward force, which is finally transmitted to the central tube 2 under the action of the locking spring 9, and the unlocking sleeve 7 cannot move upward relative to the central tube 2. The slip 8 will not expand a second time to form an anchor with the sleeve, causing the device to be unable to be unlocked.

[0021] 2. Design of soluble locking block mechanism: Figure 4 As shown in CC, the three soluble lock blocks 30 are uniformly distributed in the circumferential key groove of the unlocking sleeve 7, as shown in FIG. Figure 1The outer boss of the soluble lock block 30 shown falls into the groove of the upper cone 5, and the boss of the inner center pipe 2 is limited. Sealing rubber rings are set inside and outside the soluble lock block 30 to seal the soluble lock block 30 from contacting the well fluid. When unsealing, the oil pipe is lifted, the upper joint 1 and the center pipe 2 move upward, the limiting lock ring 12 loses the limit of the lower cone 13 and expands outward, shearing the unsealing shear nail 3, and the upper boss of the center pipe 2 moves upward to the step of the upper cone 5. The soluble lock block 30 in the unblocking sleeve 7 loses the support of the center pipe 2 and can be recovered. The unblocking sleeve 7 and the upper cone 5 lose the fixation of the soluble lock block 30 and separate. The pipe string slip 8 is continued to be lifted and recovered. The inner seal of the soluble lock block 30 falls below the step of the center pipe 2 and loses the seal. The soluble lock block 30 contacts the well fluid. If it cannot be lifted, the upper cone 5 and the unblocking sleeve 7 are completely separated after the soluble lock block 30 dissolves and the pipe string is lifted.

[0022] 3. The structure is designed to prevent misoperation when encountering obstacles, and the unsealing shear nail 3 is not subjected to force, such as Figure 1 As shown in the figure, when the pipe column slip cover 6 is lifted up and encounters resistance, the force is transmitted to the unlocking sleeve 7 through the slip cover cap 4. Figure 2 The opening design of the limiting lock ring 12 shown in the cross-sectional view AA can be located in the groove of the center tube 2, and the outer circle is pressed and limited by the lower cone 13. At this time, the limiting lock ring 12 cannot expand outward, and the unlocking sleeve 7 cannot move downward under the obstruction of the limiting lock ring 12 to transmit the force to the center tube 2, and the center tube 2 is threadedly connected to the upper joint 1, and there is no relative displacement between the upper joint 1 and the upper cone 5, so the unlocking shear nail 3 is not subjected to force; the lower cone 13 can only move upward in one direction on the unlocking sleeve 7 through the locking spring 2 11. When moving downward, the force is transmitted to the unlocking sleeve 7 through the locking spring 2 11. The unlocking sleeve 7 transmits the force to the center tube 2 and the upper joint 1 under the action of the locking spring 2 11, and the unlocking shear nail 3 is not subjected to force.

[0023] 4. The structure is designed to prevent misoperation when encountering obstacles, and the sealing shear pins 24 are not subjected to force. Figure 1 The upper cylinder 22, the lower cylinder 25, the seat sealing sleeve 19, and the lower pressure ring 16 are threadedly connected together, and the block 23 between the upper cylinder 22 and the center tube 2 is limited by Figure 3 As shown in the cross-sectional view BB, a clamping block 23 is installed in the groove at the lower end of the upper cylinder 22 and is located in the annular groove of the center tube 2. The setting shear pins 24 connect the lower setting piston 26 and the upper cylinder 22 and press the clamping block 23 at the same time. The lower setting piston 26 is not subjected to force in the annulus between the lower cylinder 25 and the lower joint 28, and the setting shear pins 24 are not subjected to force. The device can operate correctly when encountering resistance.

[0024] 5. A dual-stage setting piston is designed to increase the setting force: The first annular cavity between the upper and lower cylinders 22, 25, and the center tube 2 generates an upward thrust, representing the first-stage setting piston assembly. The second annular cavity between the upper cylinder 22, the setting sleeve 19, and the center tube 2 generates an upward thrust, representing the second-stage setting piston assembly. The combined thrust of the two annular cavities pushes the setting sleeve 19 and the lower pressure ring 16 to compress the rubber cartridge for setting. Large-diameter retrievable gas well anchoring and isolation devices are limited by their large diameter, resulting in a small setting piston area and a loose setting of the rubber cartridge, which cannot withstand the high differential pressure required. The dual-stage setting piston is designed to increase the setting force. Calculations show that the setting force generated by the dual-stage setting piston is greater than the force generated when the rubber cartridge is subjected to the maximum differential pressure. This ensures that the rubber cartridge will not be further compressed when subjected to a differential pressure and will not be retracted when subjected to low pressure, thereby improving sealing performance.

[0025] Setting process: The oil pipe is pressurized to let liquid flow into the upper and lower liquid inlet holes in the center pipe. The hydraulic pressure generates a downward thrust on the lower setting piston 26, shearing the setting shear pin 24. The lower setting piston 26 moves downward, and the block 23 loses its external restriction and pops out from the ring groove of the center pipe 2. The hydraulic pressure generates an upward thrust on the first annular cavity between the upper cylinder 22, the lower cylinder 25 and the center pipe 2, and generates an upward thrust on the second annular cavity between the upper cylinder 22, the setting seal sleeve 19 and the center pipe 2. The thrust of the two annular cavities is superimposed to push the upper cylinder 22 and the lower cylinder 25 together. , the seat sealing sleeve 19, the lower pressure ring 16, the rubber cylinder shaft 14, the lock spring seat 17, the lock spring 3 18, the lower cone 12, and the lock spring 2 11 move upward, the slips 8 expand and form an anchor with the casing, and the oil pipe pressure continues to increase. The upper cone 5 and the rubber cylinder shaft 14 do not move under the limit of the slips 8. The upper cylinder 22, the lower cylinder 25, the seat sealing sleeve 19, and the lower pressure ring 16 continue to move upward to compress the rubber cylinder and the casing to form a seal. At the same time, the lock spring 3 18 locks the seat sealing sleeve 19. When the oil pipe pressure is relieved, the seat sealing sleeve will not move downward, and the rubber cylinder naturally forms a seal with the casing;

[0026] Injecting carbon dioxide: Inject carbon dioxide into the tubing, and seal the casing with a rubber sleeve. Carbon dioxide will not enter the upper casing annulus, thus protecting the casing. Slip 8 does not come into contact with carbon dioxide gas on the upper part of the rubber sleeve, thus increasing the effective period of anchoring.

[0027] Unsealing process: lift the oil pipe, the upper joint and the center pipe go up, the limit lock ring 12 loses the limit of the lower cone 13 and expands outward, cuts the unsealing shear nail 3, the upper boss of the center pipe 2 goes up to the step of the upper cone 5, the soluble lock block 30 in the unblocking sleeve 7 loses the support of the center pipe 2 and can be recovered, the unblocking sleeve 7 and the upper cone 5 lose the fixation of the soluble lock block 30 and separate, continue to lift the pipe string slip 8 to be recovered, the inner seal of the soluble lock block 30 falls below the step of the center pipe 2 and loses the seal, the soluble lock block 30 contacts the well fluid, if it cannot be lifted, wait until the soluble lock block dissolves, the upper cone 5 and the unblocking sleeve 7 are completely separated before lifting the pipe string, continue to lift the pipe string, and the upper cone 5 is hung The slip cover cap 4 is held, and the slip cover 6 and the slip 8 go up together. The slip cover 6 hangs on the lower cone 13. The lower cone 13 is threadedly connected to the rubber cylinder shaft 14 and is hung on the unlocking sleeve 7 through the locking spring 2 11. The unlocking sleeve 7 is hung on the center tube 2 through the locking spring 1 9. The upper anchoring part and the center tube 2 form a whole and go up to transmit the force to the rubber cylinder shaft 14. At this time, the petal thread at the lower end of the rubber cylinder shaft 14 is in the groove of the center tube 2, and the thread connected to the lock spring seat 17 at the lower end of the rubber cylinder shaft 14 loses the restriction of the center tube 2 and is recovered. The rubber cylinder shaft 14 is threadedly separated from the lock spring seat 17, and the rubber cylinder shaft 14 and the upper anchoring device go up together, the rubber cylinder is recovered, and the unsealing is completed.

Claims

1. A large-diameter removable gas well anchoring and sealing device, comprising an upper joint (1) and a central tube (2), wherein the inner wall of the lower end of the upper joint (1) is threadedly connected to the central tube (2), and characterized in that: The outer wall of the lower end of the upper joint (1) is connected to the upper cone (5) through the unblocking shear nail (3), and the outer side of the lower part of the upper cone (5) is provided with a cone surface. The upper cone (5) is sleeved on the outer wall of the central tube (2), and the outer wall of the central tube (2) is also sleeved with an unblocking sleeve (7). The upper part of the unblocking sleeve (7) is located in the annular cavity between the upper cone (5) and the central tube (2). The inner wall of the middle part of the unblocking sleeve (7) and the outer wall of the central tube (2) corresponding to the middle part of the unblocking sleeve (7) are both provided with an annular groove and the annular groove is provided. A one-way locking spring (9) is installed in the groove, and a locking ring groove is provided on the outer wall of the corresponding center tube (2) below the lower end surface of the unlocking sleeve (7), and a limiting locking ring (12) with an opening is installed in the locking ring groove. A part of the limiting locking ring (12) is located in the locking ring groove, and the other part of the limiting locking ring (12) is located at the lower end surface of the unlocking sleeve (7). The unlocking sleeve (7) is aligned with the end surface of the limiting locking ring (12); the lower end of the unlocking sleeve (7) is sleeved with a lower cone (13), and the lower cone (1 3) The outer side of the upper part is provided with a conical surface, the upper inner wall of the lower cone (13) is provided with a lock groove and a one-way lock spring 2 (11) is installed in the lock groove, the lock spring 2 (11) cooperates with the thread teeth on the outer wall of the lower end of the unlocking sleeve (7), and the middle part of the unlocking sleeve (7) is provided with a slip (8), the upper conical surface of the slip (8) is pressed on the conical surface of the upper cone (5), the lower conical surface of the slip (8) is pressed on the conical surface of the lower cone (13), and the hole on the outer wall of the middle part of the slip (8) is installed. There is a spring (10), the outer cover of the slip (8) is provided with a slip cover (6), the slip cover (6) is provided with a window, the upper end of the slip cover (6) is threadedly connected to the slip cover cap (4), the slip cover cap (4) is sleeved on the shoulder of the outer wall of the upper cone (5), and the lower end of the slip cover (6) is clamped with the lower cone (13); the lower end of the lower cone (13) is threadedly connected to the rubber cylinder shaft (14), and the outer wall of the rubber cylinder shaft (14) is sleeved with the rubber cylinder assembly (15) and the lower pressure ring (16) in sequence;The lower end of the rubber cylinder shaft (14) is threadedly connected to the lock spring seat (17), and the outer wall of the lower end of the lock spring seat (17) is installed with a one-way lock spring three (18), and the outer wall of the lower end of the lock spring seat (17) is sleeved with a seat sealing sleeve (19), and the lock spring three (18) is matched with the thread teeth of the inner wall of the seat sealing sleeve (19). The lock spring seat (17) and the seat sealing sleeve (19) are locked in one direction by the lock spring three (18). The seat sealing sleeve (19) is threadedly connected to the lower pressure ring (16). The lower end surface of the seat sealing sleeve (19) is provided with an upper seat sealing piston (20), and the inner wall of the lower end of the upper seat sealing piston (20) is connected to the outer thread of the split nut (21). The inner thread of the split nut (21) is connected to the center tube (2), and the outer wall of the lower end of the seat sealing sleeve (19) is connected to the outer thread of the split nut (21). The upper thread is connected to the upper end of the upper cylinder (22), and the block (23) is installed in the groove of the lower end of the upper cylinder (22), and the inner wall of the block (23) is located in the annular groove of the center tube (2). The lower end of the center tube (2) is threadedly connected to the limit nut (29) and the lower joint (28) in sequence. The upper wall of the limit nut (29) and the upper part of the lower joint (28) are provided with a lower setting piston (26). The lower setting piston (26) is connected to the upper cylinder (22) by a setting shear pin (24). At the same time, the lower setting piston (26) presses the block (23). The lower end of the upper cylinder (22) is threadedly connected to the lower cylinder (25). The outer wall of the lower joint (28) is threadedly connected to the guide cap (27), and the guide cap (27) is clamped with the lower cylinder (25); The upper portion of the unlocking sleeve (7) is provided with three evenly distributed key slots, and an annular groove is provided on the inner wall of the upper cone (5) corresponding to the unlocking sleeve (7). The key slot on the unlocking sleeve (7) corresponds to the annular groove on the upper cone (5), and a soluble locking block (30) is provided in the key slot on the unlocking sleeve (7).

2. The large-diameter removable gas well anchoring and sealing device according to claim 1, characterized in that: An inner sealing ring (31) is installed between the upper portion of the unlocking sleeve (7) and the central tube (2), and an outer sealing ring (32) is installed between the upper portion of the unlocking sleeve (7) and the upper cone (5).

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