A device and method for repairing a reduced diameter of an expanded sleeve

Abstract

This invention belongs to the field of well completion and workover technology in oil and gas field drilling. It discloses a repair device and method for reducing the diameter of an expansion casing. The repair device includes, from bottom to top, a guide shoe, a tubing anchoring assembly, a pressure relief valve assembly, an expansion cone assembly, and a thrust cylinder assembly, connected sequentially. The guide shoe generates liquid pressure by creating pressure. The tubing anchoring assembly anchors the entire repair device to the inner wall of the expansion casing. The pressure relief valve assembly sends a liquid pressure reduction signal to the surface to indicate that the repair operation is complete. The expansion cone assembly radially compresses the reduced diameter area to expand and repair it. The thrust cylinder assembly provides the hydraulic power for the repair. This invention avoids over-repairing the expansion casing; the anchor claws can automatically reset after the diameter reduction repair, and the repair device is unlocked; this invention achieves in-situ diameter reduction repair without milling, with a high success rate on the first attempt. After diameter reduction repair, a flared opening is formed at the end of the expansion casing, facilitating the guidance of subsequent tools.

Description

Technical Field

[0001] This invention relates to the field of well completion and workover technology in oil and gas field drilling, and particularly to a repair device and method for reducing the diameter of expansion casing. Background Technology

[0002] Expandable casing technology is a new technology in the petroleum industry. This technology involves lowering the casing into the well and using mechanical or hydraulic power to drive an expansion cone. Through cold extrusion expansion, the inner or outer diameter of the casing is increased to the designed size, thus achieving the intended engineering purpose. This technology is mainly applied in several fields, including casing repair in damaged wells, tee pipe suspension in old wells, and sealing of complex formations in open-hole wells.

[0003] During the radial expansion of the expansion casing, the expansion casing will curl inward due to frictional viscosity. Specifically, the end of the expanded casing will shrink after expansion. This shrinkage will reduce the inner diameter of the expansion casing, which will not only affect the outer diameter of the subsequent tools, but also form a step, causing the tools to get stuck at the shrinkage position. The conventional method to solve this problem in engineering is to use a special grinding shoe to grind away the shrinkage section of the expansion casing. However, this milling process for the expansion casing has the following shortcomings: (1) After milling the shrinkage section of the expansion casing, there will be burrs, which can easily damage the packer sleeve that is subsequently run in; (2) Milling can easily cause the expansion casing string to move, affecting its sealing performance and damaging the integrity of the wellbore; (3) Milling also carries the risk of damaging the upper casing. Summary of the Invention

[0004] The purpose of this invention is to provide a repair device and method for shrinking the diameter of an expansion sleeve, so as to solve the problems of milling damage and poor sealing of the expansion sleeve caused by existing shrinkage repair methods.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] This invention first provides a repair device for the reduction in diameter of an expansion sleeve, comprising, from bottom to top, the following components:

[0007] The guide shoe has a conical ball seat at its center to receive the sealing ball;

[0008] A tubular anchoring assembly, the bottom end of which is connected to the guide shoe; the tubular anchoring assembly includes an anchor claw that can extend radially to anchor to the inner wall of the expansion sleeve;

[0009] A pressure relief valve assembly includes a pressure relief valve center tube, a pressure relief sleeve, and a first return spring. The bottom end of the pressure relief valve center tube is connected to the pipe column anchoring assembly. A pressure relief hole is provided on the pipe wall of the pressure relief valve center tube. The first return spring and the pressure relief sleeve are both sleeved on the pressure relief valve center tube. The two ends of the first return spring abut against the top end of the pipe column anchoring assembly and the bottom end of the pressure relief sleeve, respectively. The top end of the pressure relief sleeve abuts against the stepped surface of the outer side wall of the pressure relief valve center tube. The pressure relief sleeve can slide along the axial direction of the pressure relief valve center tube to seal or open the pressure relief hole.

[0010] An expansion cone assembly includes an expansion cone and a push sleeve. The top end of the push sleeve abuts against the bottom end of the expansion cone. The side wall of the push sleeve is provided with a first liquid outlet hole. The inner diameter of the push sleeve is larger than the outer diameter of the pressure relief valve center tube, and the inner diameter of the push sleeve is smaller than the outer diameter of the pressure relief sliding sleeve. The outer side wall of the expansion cone is provided with a conical surface, which can abut against the reduced diameter position of the expansion sleeve.

[0011] A thrust cylinder assembly includes an upper central tube, a variable-thread connector, a lower central tube, a piston, an end cap, and an outer sleeve. The upper and lower central tubes are connected via the variable-thread connector. The top end of the upper central tube is connected to an upper connector, and the bottom end of the lower central tube is connected to the top end of the pressure relief valve central tube. The outer sleeve is fitted onto the variable-thread connector. The piston is fitted onto the lower central tube, and the bottom end of the piston passes through an expansion cone and is connected to the thrust sleeve. The top end of the expansion cone abuts against the stepped surface of the piston's outer wall. The top end of the piston is connected to the outer sleeve. A second fluid flow channel is formed between the inner wall of the piston and the outer wall of the lower central tube. A second fluid outlet is provided on the side wall of the piston, and the second fluid flow channel communicates with the second fluid outlet. The end cap is connected to the top end of the outer sleeve and is connected to the upper central tube via a shear pin. A first fluid inlet is provided on the side wall of the lower central tube. A cavity is formed between the top end of the piston, the variable-thread connector, and the outer sleeve, and the first fluid inlet communicates with the cavity.

[0012] Optionally, the angle between the conical surface of the expansion cone and the axial direction is 15°, the outer diameter of the bottom end of the expansion cone is smaller than the inner diameter of the reduced diameter, and the outer diameter of the top end of the expansion cone is larger than the inner diameter of the expansion sleeve.

[0013] Optionally, the tubing anchoring assembly further includes a tubing body, a second return spring, and a cover plate. The bottom end of the tubing body is connected to the guide shoe, and the top end is connected to the central tube of the pressure relief valve. The tubing body has a radial groove, and the bottom of the radial groove has a second liquid inlet hole. The second liquid inlet hole penetrates the side wall of the tubing body. The base end of the anchor claw is placed in the radial groove and covers the second liquid inlet hole. The anchoring end of the anchor claw has teeth and a long groove. The long groove contains a second return spring, which abuts against the cover plate. The cover plate passes through the long groove, and both ends of the cover plate are fixed to the tubing body. The teeth are distributed on both sides of the long groove. When the anchor claw extends radially, the long groove slides relative to the cover plate and compresses the second return spring. The teeth are anchored to the expansion sleeve.

[0014] Optionally, the bottom of the long groove is provided with a spring hole, and one end of the second reset spring is disposed in the spring hole for limiting.

[0015] Optionally, the anchor claws are provided in at least three sets, the three sets of anchor claws are spaced apart and staggered along the long axis of the pipe body, each set includes at least three anchor claws, and the at least three anchor claws are spaced apart and evenly arranged along the circumference of the pipe body.

[0016] Optionally, the outer wall of the anchor claw is provided with a circumferential annular groove, and a sealing ring is provided in the annular groove, the sealing ring being sandwiched between the anchor claw and the radial groove.

[0017] Optionally, the pressure relief valve has a plurality of sealing grooves on its central tube, and the plurality of sealing grooves are respectively located at the upper and lower ends of the pressure relief hole, and the sealing grooves contain vulcanized sealing strips.

[0018] Optionally, multiple first liquid outlet holes are provided, and the multiple first liquid outlet holes are spaced apart along the axial and circumferential directions of the push sleeve.

[0019] Using the aforementioned expansion sleeve diameter reduction repair device, this invention also provides a method for repairing expansion sleeve diameter reduction, which repairs the diameter reduction at the end of the expansion sleeve, comprising the following steps:

[0020] S1, the expansion casing diameter reduction repair device is lowered into the well to the diameter reduction position of the expansion casing, the guide shoe is inserted into the expansion casing, and it is continued to be lowered until the cone surface of the expansion cone abuts the end of the diameter reduction.

[0021] S2, a sealing ball is placed into the repair device for the reduced diameter of the expansion sleeve. The sealing ball falls into the ball seat inside the guide shoe and begins to pressurize. The anchor claws of the tube anchoring assembly extend radially under hydraulic action and anchor to the inner wall of the expansion sleeve.

[0022] S3, continue to pressurize, the shear pin on the end cap is sheared off, the piston pushes the expansion cone downward along the axial direction, the cone surface of the expansion cone radially squeezes the reduced diameter, and the expansion sleeve forms a flared mouth at the reduced diameter;

[0023] S4, when the expansion cone moves downward, it pushes the push sleeve to move downward. The push sleeve pushes the pressure relief sleeve to move downward and compresses the first return spring until the top of the push sleeve is lower than the pressure relief hole. The pressure relief hole opens and the pressure drops suddenly, indicating that the diameter reduction repair operation is completed.

[0024] S5, the ground pump stops and pressure is released. The pressure release sleeve is reset under the elastic force of the first reset spring, the anchor claw is retracted, the anchoring is released, and the expansion sleeve diameter reduction repair device is taken out.

[0025] Optionally, the method for repairing the reduced diameter of the expansion sleeve further includes step S6, repeating steps S1-S5 to repair the reduced diameter multiple times.

[0026] The beneficial effects of this invention are:

[0027] The expansion sleeve diameter reduction repair device of the present invention uses a sealing ball to pressurize and generate liquid pressure. Using this liquid pressure as power, it can repair the diameter reduction at the end of the expansion sleeve after anchoring. When the pressure relief valve assembly releases pressure, the ground receives a pressure drop signal and stops pressurizing, avoiding over-repair of the expansion sleeve. After the diameter reduction is repaired, the anchor claws can automatically reset due to the pump stoppage and pressure relief, facilitating recycling and reuse. The repair device achieves milling-free diameter reduction repair, the repair process does not cause damage to the expansion sleeve, does not affect the sealing performance of the expansion sleeve, achieves in-situ diameter reduction repair, and has a high success rate of one-time repair.

[0028] The present invention relates to a method for repairing the reduced diameter of an expansion casing. This method involves deploying a sealing ball to create pressure, which in turn generates liquid pressure. The expansion cone moves downwards under hydraulic pressure to radially compress the reduced diameter area, achieving the repair effect. After the repair, the pressure relief valve assembly releases pressure. Upon receiving a pressure reduction signal, the surface stops pressurizing the liquid. As the liquid pressure decreases, the anchor claws automatically reset, facilitating the retrieval of the repair device. This method achieves in-situ repair of the reduced diameter at the end of the downhole expansion casing without damaging the casing. The repair does not affect the sealing performance of the expansion casing. The repair creates a flared opening at the end of the expansion casing, facilitating the guidance of subsequent tools and preventing jamming. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the reduced diameter at the end of the expansion sleeve;

[0030] Figure 2 This is a schematic diagram of the structure of a repair device for reducing the diameter of an expansion sleeve according to the present invention (the long shaft is shown in segments).

[0031] Figure 3 yes Figure 2 Enlarged view of region A in the middle;

[0032] Figure 4 yes Figure 2 Enlarged view of region B in the middle;

[0033] Figure 5 yes Figure 2 Enlarged diagram of region C in the middle;

[0034] Figure 6 This is a schematic diagram of the usage state of a repair device for reducing the diameter of an expansion sleeve according to the present invention;

[0035] Figure 7 This is a schematic diagram showing the position where the conical surface of the expansion cone abuts against the reduced diameter in an embodiment of the present invention;

[0036] Figure 8 yes Figure 6 Enlarged schematic diagram of region D in the middle;

[0037] Figure 9 This is a schematic diagram of the structure after the end of the expansion sleeve has been repaired by reducing its diameter.

[0038] In the picture:

[0039] 100. Expansion sleeve; 200. Reduction diameter; 300. Sealing ball; 400. Bell mouth;

[0040] 1. Guide shoe; 11. Ball seat; 2. Tube string anchoring assembly; 21. Anchor claw; 211. Sealing ring; 22. Tube string body; 221. Radial groove; 222. Second inlet hole; 23. Second return spring; 24. Cover plate; 3. Pressure relief valve assembly; 31. Pressure relief valve center tube; 311. Pressure relief hole; 312. Vulcanized sealing strip; 32. Pressure relief sleeve; 33. First return spring; 4. Expansion cone assembly; 41. Expansion cone... 411. Conical surface; 42. Push sleeve; 421. First liquid outlet; 422. First liquid flow channel; 5. Thrust cylinder assembly; 51. Upper central tube; 52. Variable thread connector; 53. Lower central tube; 531. Second liquid flow channel; 532. First liquid inlet; 533. Cavity; 54. Piston; 541. Second liquid outlet; 55. End cap; 551. Shear pin; 56. Outer sleeve; 6. Upper connector. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0042] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used solely for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are merely used for descriptive distinction and have no special meaning. The term "multiple" should be understood as two or more.

[0045] This invention provides a repair device and method for repairing the reduced diameter of an expansion sleeve, such as... Figure 1 As shown, after radial expansion, the expansion sleeve 100 will form a reduced diameter 200 at its end due to frictional adhesion. In order to overcome the problems of repairing the reduced diameter 200 by milling in the prior art, this invention abandons the milling scheme and provides a new device and method for repairing the reduced diameter of the expansion sleeve. It can repair the reduced diameter 200 at the end of the expansion sleeve 100 in situ without damaging the expansion sleeve 100 or affecting the sealing performance of the expansion sleeve 100 itself.

[0046] like Figure 2 As shown, the expansion sleeve diameter reduction repair device provided by the present invention includes, from bottom to top, a guide shoe 1, a tube string anchoring assembly 2, a pressure relief valve assembly 3, an expansion cone assembly 4, and a thrust cylinder assembly 5. Unless otherwise specified, the connection method is generally a threaded connection.

[0047] The center of the shoe 1 is provided with a conical ball seat 11 to receive the sealing ball 300, such as Figure 2 The ball seat 11 is a tapered hole with the opening facing upwards. After the sealing ball 300 falls into it from the top, it can be locked inside the ball seat 11 to seal the through hole on the shoe 1 and achieve pressure suppression.

[0048] The bottom end of the pipe anchoring assembly 2 is threadedly connected to the guide shoe 1; the pipe anchoring assembly 2 includes an anchor claw 21, which can extend radially to lock onto the inner wall of the expansion sleeve 100; when repairing the reduced diameter 200 by the expansion sleeve reduction repair device of the present invention, the anchor claw 21 needs to be anchored first in order to fix the expansion sleeve reduction repair device.

[0049] like Figure 4 The pressure relief valve assembly 3 includes a pressure relief valve center tube 31, a pressure relief sleeve 32, and a first return spring 33. The bottom end of the pressure relief valve center tube 31 is connected to the pipe column anchoring assembly 2. A pressure relief hole 311 is provided on the pipe wall of the pressure relief valve center tube 31. The pressure relief sleeve 32 and the first return spring 33 are both sleeved on the pressure relief valve center tube 31, and the two ends of the first return spring 33 respectively abut against the top end of the pipe column anchoring assembly 2 and the bottom end of the pressure relief sleeve 32. The top end of the pressure relief sleeve 32 abuts against the stepped surface of the outer side wall of the pressure relief valve center tube 31. The pressure relief sleeve 32 can slide along the axial direction of the pressure relief valve center tube 31 to seal or open the pressure relief hole 311. Figure 2 As shown, the bottom end of the pressure relief valve center tube 31 is threadedly connected to the pipe anchoring assembly 2. In the initial state, the top end of the pressure relief sleeve 32 abuts against the stepped surface of the outer wall of the pressure relief valve center tube 31, so that the pressure relief sleeve 32 can only slide downwards; the pressure relief sleeve 32 seals the pressure relief hole 311. When the pressure relief sleeve 32 slides downwards, it will compress the first return spring 33 until the top end of the pressure relief sleeve 32 is lower than the pressure relief hole 311, the pressure relief hole 311 opens, and the liquid in the pipe flows out to relieve pressure. At this time, the ground shows that the pipe is depressurized, indicating that the repair process of the 200mm diameter reduction is over and the pump is stopped. The liquid pressure in the pipe decreases, and the pressure relief sleeve 32 will slide upwards under the action of the first return spring 33 until it abuts against the stepped surface of the outer wall of the pressure relief valve center tube 31 again.

[0050] The expansion cone assembly 4 includes an expansion cone 41 and a push sleeve 42. The top end of the push sleeve 42 abuts against the bottom end of the expansion cone 41. The side wall of the push sleeve 42 is provided with a first liquid outlet hole 421. The inner diameter of the push sleeve 42 is larger than the outer diameter of the pressure relief valve center tube. The outer side wall of the expansion cone 41 is provided with a conical surface 411, which can abut against the reduced diameter 200 position of the expansion sleeve 100.

[0051] like Figure 2As shown, in the initial position, the push sleeve 42 is fixed to the piston 54 of the thrust cylinder assembly 5 by a pin or a threaded connection. The expansion cone 41 is sleeved on the outer wall of the piston 54. Under the action of liquid pressure, the piston 54 moves downward, pushing the expansion cone 41 and the push sleeve 42 downward and shearing the shear pin 551 to continue moving downward until the bottom end of the push sleeve 42 abuts against the top end of the pressure relief sleeve 32, pushing the pressure relief sleeve 32 to overcome the elastic force of the first return spring 33 and continue moving downward. Therefore, in the above series of downward movement transmission processes, the cone surface 411 of the expansion cone 41 moves downward while squeezing the reduced diameter 200 to achieve the diameter reduction 200 repair. As can be seen, the 200mm diameter reduction repair achieves in-situ repair and expansion. The expansion size is controlled by the outer diameter of the end of the expansion cone 41 or the size of the cone surface 411. By abandoning the milling repair method, this invention achieves non-destructive 200mm diameter reduction repair of the expansion sleeve 100. Liquid pressure is used as the driving force to achieve the slow descent repair of the expansion cone 41. Therefore, it does not affect the sealing performance of the expansion sleeve 100, and the expansion sleeve 100 can be smoothly connected to the subsequent lowering tool.

[0052] like Figure 2 and Figure 5 The thrust cylinder assembly 5 includes an upper central tube 51, a variable thread connector 52, a lower central tube 53, a piston 54, an end cap 55, and an outer sleeve 56. The upper central tube 51 and the lower central tube 53 are connected by the variable thread connector 52. Preferably, the two ends of the variable thread connector 52 are threaded to the bottom end of the upper central tube 51 and the top end of the lower central tube 53, respectively. The top end of the upper central tube 51 is connected to an upper connector 6, which is a connection part for connecting the top drilling tool. It is a commonly used upper connector 6 component in the drilling field. The upper connector 6 can be threaded or pinned to the top end of the upper central tube 51. The bottom end of the lower central tube 53 is connected to the top end of the pressure relief valve central tube 31, and the outer sleeve 56 is fitted onto the variable thread connector 52. Figure 5The outer diameter of the variable thread connector 52 is larger than the outer diameters of the upper central tube 51 and the lower central tube 53. It is connected to the external threads of the upper central tube 51 and the lower central tube 53 respectively through internal threads at both ends. Optionally, a pin connection can be added or used alone. The outer sleeve 56 is fitted onto the outer wall of the variable thread connector 52 and is provided with multiple sealing rings to seal the gap between them. Piston 54 is fitted onto lower central tube 53, and an expansion cone 41 passes through the bottom end of piston 54 and is connected to push sleeve 42. The top end of expansion cone 41 abuts against the stepped surface of the outer wall of piston 54. The top end of piston 54 is connected to outer sleeve 56. A second liquid flow channel 531 is formed between the inner wall of piston 54 and the outer wall of lower central tube 53. A second liquid outlet hole 541 is provided on the side wall of piston 54. The second liquid flow channel 531 is connected to the second liquid outlet hole 541. End cap 55 is connected to the top end of outer sleeve 56 and is connected to upper central tube 51 by shear pin 551. A first liquid inlet hole 532 is provided on the side wall of lower central tube 53. A cavity 533 is formed between the top end of piston 54, the bottom end of variable thread connector 52, and outer sleeve 56. The first liquid inlet hole 532 is connected to cavity 533. Figure 5 The inner and outer walls of the piston 54 are respectively sealed to the lower central tube 53 and the outer sleeve 56. Multiple sealing rings are provided to seal the cavity 533, so that the liquid in the first liquid inlet hole 532 can enter the cavity 533 and form liquid pressure that can exert a downward thrust on the piston 54.

[0053] The expansion sleeve diameter reduction repair device of the present invention uses a sealing ball 300 to seal the through hole on the guide shoe 1 to form liquid pressure during repair. Using the liquid pressure as power, the diameter reduction 200 at the end of the expansion sleeve 100 can be repaired after the expansion sleeve 100 is anchored. The pressure relief valve assembly releases pressure to indicate that the diameter reduction 200 repair is completed. The ground pump stops, and the liquid pressure in the pipe is unloaded and reduced, avoiding over-repair of the expansion sleeve 100. After the liquid pressure is unloaded, the anchor claw 21 can reset itself, which is convenient for recycling and reuse. The repair device realizes the repair of the diameter reduction 200 without grinding and milling. The repair process will not cause damage to the expansion sleeve 100, will not affect the sealing performance of the expansion sleeve 100, realizes the in-situ diameter reduction 200 repair, and has a high success rate of one-time repair.

[0054] Optionally, the angle between the cone surface 411 of the expansion cone 41 and the axial direction is 15°, the outer diameter of the bottom end of the expansion cone 41 is smaller than the inner diameter of the reduced diameter 200, and the outer diameter of the top end of the expansion cone 41 is larger than the inner diameter of the expansion sleeve 100.

[0055] To achieve a better repair effect for the reduced diameter 200 and avoid the influence of adhesive forces on the repair, in this embodiment, the top of the conical surface 411 is set to have an outer diameter larger than the inner diameter of the expansion sleeve 100, leaving a margin to avoid secondary reduction of diameter 200. The vertical inclination angle of the conical surface 411 is preferably 15° to achieve circumferential compression of the reduced diameter 200, and to gradually expand the diameter 200 radially, avoiding damage to the expansion sleeve 100 caused by excessive speed or pressure. If the inclination angle of the conical surface 411 is too small, it will affect the repair effect of the reduced diameter 200; if it is too large, it may cause damage to the end of the expansion sleeve 100. Preferably, the top of the conical surface 411 should have a rounded transition, i.e., a chamfer, to avoid damage when the top contacts the inner wall of the expansion sleeve 100.

[0056] Optionally, such as Figure 2 and Figure 3 The column anchoring assembly 2 also includes a column body 22, a second return spring 23, and a cover plate 24. The bottom end of the column body 22 is connected to the guide shoe 1, and the top end is connected to the pressure relief valve center pipe 31. The column body 22 is provided with a radial groove 221 (see [reference]). Figure 6 The bottom of the radial groove 221 is provided with a second liquid inlet hole 222, which penetrates the side wall of the column body 22. The base end of the anchor claw 21 is placed in the radial groove 221 and covers the second liquid inlet hole 222. The anchoring end of the anchor claw 21 is provided with teeth and a long groove. A second return spring 23 is provided in the long groove. The second return spring 23 abuts against the cover plate 24. The cover plate 24 is inserted into the long groove and its two ends are fixed to the column body 22. The teeth are distributed on both sides of the long groove. When the anchor claw 21 extends radially, the long groove slides relative to the cover plate 24 and compresses the second return spring 23. The teeth are anchored to the expansion sleeve 100.

[0057] Figure 3 The illustrated tubular anchoring assembly 2 is a partial cross-sectional view. The bottom of the long groove has spring holes, and one end of the second return spring 23 is positioned within these spring holes for limiting its movement. In this embodiment, two spring holes are formed at the bottom of the long groove. One end of each of the two second return springs 23 is placed within and fixed to the two spring holes. Initially, the second return springs 23 are in their natural state. When liquid enters the second inlet hole 222, it drives the anchor claw 21 to move towards the bottom of the groove away from the radial groove 221, thus extending radially to anchor the inner wall of the expansion sleeve 100. The long groove and the cover plate 24 move relative to each other, and the second return spring 23 is compressed and abuts against the anchor claw 21 and the cover plate 24. When the liquid pressure decreases, since the cover plate 24 is fixed to the tubular body 22, the anchor claw 21 can move towards the bottom of the radial groove 221 under the elastic force of the second return spring 23, achieving radial contraction and releasing the anchor. The tubular anchoring assembly 2 provided in this embodiment has a small structure, and the anchoring unlocking and locking are controlled by liquid pressure, resulting in high repair efficiency, easy implementation, and reuse.

[0058] Optionally, the anchor claw 21 is provided with at least three sets, the three sets of anchor claw 21 are spaced apart and staggered along the long axis of the column body 22, each set includes at least three anchor claws 21, and the at least three anchor claws 21 are spaced apart and evenly arranged along the circumference of the column body 22.

[0059] like Figure 2 As shown, in this embodiment, three sets of anchor claws 21 are arranged along the long axis of the pipe body 22. Each set has three pairs of anchor claws 21, and the three pairs of anchor claws 21 are evenly distributed at 120° in the circumferential direction to ensure uniform force when anchored to the expansion sleeve 100. The three sets of anchor claws 21 are arranged radially in a staggered and evenly distributed manner, which can achieve better circumferential anchoring effect.

[0060] Optionally, the outer wall of the anchor claw 21 is provided with a circumferential annular groove, and a sealing ring 211 is provided in the annular groove. The sealing ring 211 is sandwiched between the anchor claw 21 and the radial groove 221.

[0061] like Figure 3 In this embodiment, the body of the anchor claw 21, i.e. the base end, adopts a cylindrical structure. The anchoring end has an elongated groove with teeth arranged on both sides of the elongated groove. The anchor claw 21 has an annular groove in its circumference, and a sealing ring 211 is provided in the annular groove. This can achieve the sealing performance of the radial groove 221 when the anchor claw 21 extends radially, preventing the leakage of liquid entering through the second liquid inlet hole 222.

[0062] Optionally, the pressure relief valve center pipe 31 is provided with multiple sealing grooves, which are respectively located at the upper and lower ends of the pressure relief hole 311, and the sealing grooves are filled with vulcanized sealing strips 312.

[0063] like Figure 4 Multiple vulcanized sealing strips 312 are provided at both the upper and lower ends of the pressure relief hole 311 to ensure the sealing of the pressure relief hole 311 during the sliding process of the pressure relief sleeve 32. Liquid will only flow out through the pressure relief hole 311 when the pressure relief sleeve 32 slides down to the top end below the pressure relief hole 311.

[0064] Optionally, multiple first liquid outlet holes 421 are provided, and the multiple first liquid outlet holes 421 are spaced apart along the axial and circumferential directions of the push sleeve 42.

[0065] like Figure 2As shown, multiple first liquid outlet holes 421 are arranged axially and circumferentially to facilitate rapid pressure relief within the pipe. The inner diameter of the push sleeve 42 is larger than the outer diameter of the lower central pipe 53, and also larger than the outer diameter of the pressure relief valve central pipe 31. This means the outer diameter of the pressure relief sliding sleeve 32 is larger than the outer diameter of the pressure relief valve central pipe 31, while the inner diameter of the push sleeve 42 is smaller than the outer diameter of the pressure relief sliding sleeve 32. This ensures that the push sleeve 42 slides downwards a certain distance before contacting the top of the pressure relief sliding sleeve 32, thus pushing the pressure relief sliding sleeve 32 downwards. When the bottom end of the push sleeve 42 contacts the top end of the pressure relief sliding sleeve 32, a first liquid flow channel 422 is formed between the inner wall of the push sleeve 42 and the outer wall of the pressure relief valve central pipe 31 (see also [reference]). Figure 6 When the top of the pressure relief sleeve 32 is lower than the pressure relief hole 311, the pressure relief hole 311 connects to the first liquid flow channel 422, the first liquid flow channel 422 connects to the second liquid flow channel 531, and the second liquid flow channel 531 connects to the second liquid outlet 541. After the liquid enters from the pressure relief hole 311, it can directly pass through the first liquid outlet 421 within the first liquid flow channel 422. The pressure relief speed is fast and the efficiency is too high. The ground can quickly and accurately receive the pressure relief signal so as to stop the pump (i.e., stop pressurizing the liquid). At the same time, in order to improve the pressure relief effect, excess high-pressure liquid will also pass through the first liquid flow channel 422, the second liquid flow channel 531, and the second liquid outlet 541 in sequence to achieve upward back discharge and pressure relief.

[0066] The present invention also provides a method for repairing the reduced diameter of an expansion sleeve, comprising the following steps: (The application of the expansion sleeve diameter repair device is described in the original text.)

[0067] S1, lower the expansion casing reduction repair device to the reduced diameter 200 position of the expansion casing 100 in the well. Insert the guide shoe 1 into the expansion casing 100 and continue lowering until the cone surface 411 of the expansion cone 41 abuts the end of the reduced diameter 200. Figure 7 ;

[0068] S2, a sealing ball 300 is placed into the repair device for the reduced diameter of the expansion sleeve. The sealing ball 300 falls into the ball seat 11 inside the guide shoe 1, and pressure is applied. Under hydraulic pressure, the anchor claws 21 of the tubing anchoring assembly 2 extend radially and anchor to the inner wall of the expansion sleeve 100. Figure 8 ;

[0069] Specifically, after the sealing ball 300 falls into the ball seat 11, due to the continuous liquid pressurization from the ground, the internal hydraulic pressure of the expansion sleeve reduction repair device increases, such as... Figure 8 High-pressure liquid enters the radial groove 221 through the second inlet hole 222 and pushes the anchor claw 21 to extend radially, finally anchoring the expansion sleeve 100. At this time, the second return spring 23 is compressed and abuts against the anchor claw 21 and the cover plate 24.

[0070] S3, continue pressurizing, the shear pin 551 on the end cap 55 is sheared off, the piston 54 pushes the expansion cone 41 downwards axially, the cone surface 411 of the expansion cone 41 radially compresses the reduced diameter 200, and the expansion sleeve 100 forms a bell mouth 400 at the reduced diameter 200, such as Figure 6 ;

[0071] Specifically, under the action of liquid pressure, high-pressure liquid enters cavity 533 through the first liquid inlet hole 532 on the lower central tube 53. The liquid pressure in cavity 533 will push piston 54 to move downward. Since the top of piston 54 is connected to outer sleeve 56 and the top of outer sleeve 56 is connected to end cap 55, after piston 54 moves downward, it will drive outer sleeve 56 and end cap 55 to move downward in sequence, thereby causing shear pin 551 between end cap 55 and upper central tube 51 to be sheared, so that piston 54 can continue to move downward.

[0072] S4, when the expansion cone 41 moves downward, it pushes the push sleeve 42 downward. The push sleeve 42 pushes the pressure relief sleeve 32 downward and compresses the first return spring 33 until the top of the push sleeve 42 is below the position of the pressure relief hole 311. The pressure relief hole opens and the pressure drops suddenly, indicating that the 200mm diameter reduction repair work is completed.

[0073] Specifically, the piston 54 moves downward, driving the expansion cone 41 and pushing the push sleeve 42 downward. When the bottom end of the push sleeve 42 abuts the top end of the pressure relief sleeve 32, and continues downward, the pressure relief sleeve 32 compresses the first return spring 33. Finally, the top end of the push sleeve 42 is below the position of the pressure relief hole 311. The pressure relief hole 311 connects the first liquid flow channel 422, the second liquid flow channel 531, and the second liquid outlet 541. High-pressure liquid enters the first liquid flow channel 422 through the pressure relief hole 311 and flows out through the first liquid outlet 421 on the push sleeve 42 to relieve pressure. At the same time, excess high-pressure liquid will also be discharged upward through the first liquid flow channel 422, the second liquid flow channel 531, and the second liquid outlet 541 to relieve pressure. After the pressure relief valve assembly 3 relieves pressure, the ground will display a pressure reduction, indicating that the repair of the reduced diameter 200 is complete. Then, the pressurization of the liquid in the pipe will stop, and the liquid pressure in the pipe will gradually return to zero.

[0074] S5, the ground pump stops and pressure is released. The pressure release sleeve 32 is reset under the elastic force of the first reset spring 33, the anchor claw 21 is retracted, the anchoring is released, and the expansion sleeve diameter reduction repair device is taken out.

[0075] After the pressure relief valve assembly 3 releases pressure through the pressure relief hole 311, the ground indicates a drop in liquid pressure, the repair of the reduced diameter 200 is complete, the ground pump stops, the liquid pressure inside the repair device for the reduced diameter expansion sleeve decreases, the pressure relief sleeve 32 returns to its original position under the action of the first return spring 33, and the anchor claw 21 retracts radially under the action of the second return spring 23 to release the anchoring, and the repaired expansion sleeve 100 is as follows. Figure 9As shown, a flared opening 400 is formed at the end of the expansion sleeve 100. The diameter of the flared opening 400 is larger than the diameter of the expansion sleeve 100 body, facilitating the guidance and installation of subsequent tools. If the reduction in diameter 200 at the end of the expansion sleeve 100 is not ideally repaired, or the size is insufficient, step S6 can be performed, repeating steps S1-S5, to repair the reduction in diameter 200 multiple times until the construction requirements are met.

[0076] The method for repairing the reduced diameter of the expansion casing of the present invention involves placing a sealing ball 300 to create liquid pressure, causing the expansion cone 41 to move downwards under hydraulic pressure to radially compress the reduced diameter 200 position, thus achieving the repair effect. After the reduced diameter 200 is repaired, the liquid pressure decreases, and the anchor claw 21 automatically resets, facilitating the retrieval of the repair device. This invention achieves in-situ repair of the reduced diameter 200 at the end of the downhole expansion casing 100 without damaging the expansion casing 100. The repair of the reduced diameter 200 does not affect the sealing performance of the expansion casing 100. After the repair, a flared opening 400 is formed at the end of the expansion casing 100, facilitating the guidance of subsequent tools and preventing jamming.

[0077] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A repair device for a reduced diameter expansion sleeve, characterized in that, Including settings from bottom to top: The guide shoe (1) has a conical ball seat (11) at its center to receive the sealing ball (300); A column anchoring assembly (2) is provided, the bottom end of which is connected to the guide shoe (1); the column anchoring assembly (2) includes an anchor claw (21) which can extend radially to anchor to the inner wall of the expansion sleeve (100); The pressure relief valve assembly (3) includes a pressure relief valve center tube (31), a pressure relief sleeve (32), and a first return spring (33). The bottom end of the pressure relief valve center tube (31) is connected to the pipe column anchoring assembly (2). The pipe wall of the pressure relief valve center tube (31) is provided with a pressure relief hole (311). The first return spring (33) and the pressure relief sleeve (32) are both sleeved on the pressure relief valve center tube (31). The two ends of the first return spring (33) abut against the top end of the pipe column anchoring assembly (2) and the bottom end of the pressure relief sleeve (32), respectively. The top end of the pressure relief sleeve (32) abuts against the stepped surface of the outer side wall of the pressure relief valve center tube (31). The pressure relief sleeve (32) can slide along the axial direction of the pressure relief valve center tube (31) to seal or open the pressure relief hole (311). The expansion cone assembly (4) includes an expansion cone (41) and a push sleeve (42). The top end of the push sleeve (42) abuts against the bottom end of the expansion cone (41). The side wall of the push sleeve (42) is provided with a first liquid outlet hole (421). The inner diameter of the push sleeve (42) is larger than the outer diameter of the pressure relief valve center tube (31), and the inner diameter of the push sleeve (42) is smaller than the outer diameter of the pressure relief sliding sleeve (32). The outer side wall of the expansion cone (41) is provided with a conical surface (411), which can abut against the reduced diameter (200) position of the expansion sleeve (100). The thrust cylinder assembly (5) includes an upper central tube (51), a variable thread connector (52), a lower central tube (53), a piston (54), an end cap (55), and an outer sleeve (56). The upper central tube (51) and the lower central tube (53) are connected by the variable thread connector (52). The top end of the upper central tube (51) is connected to an upper connector (6). The bottom end of the lower central tube (53) is connected to the top end of the pressure relief valve central tube (31). The outer sleeve (56) is fitted onto the variable thread connector (52). The piston (54) is fitted onto the lower central tube (53), and the bottom end of the piston (54) passes through the expansion cone (41) and is connected to the push sleeve (42). The top end of the expansion cone (41) abuts against the outer wall of the piston (54). On the stepped surface, the top end of the piston (54) is connected to the outer sleeve (56), and a second liquid flow channel (531) is formed between the inner wall of the piston (54) and the outer wall of the lower central tube (53). The side wall of the piston (54) is provided with a second liquid outlet (541), and the second liquid flow channel (531) is connected to the second liquid outlet (541). The end cap (55) is connected to the top end of the outer sleeve (56) and is connected to the upper central tube (51) by a shear pin (551). The side wall of the lower central tube (53) is provided with a first liquid inlet (532). A cavity (533) is formed between the top end of the piston (54), the variable thread connector (52), and the outer sleeve (56). The first liquid inlet (532) is connected to the cavity (533).

2. The repair device for the reduced diameter of the expansion sleeve according to claim 1, characterized in that, The angle between the conical surface (411) of the expansion cone (41) and the axial direction is 15°. The outer diameter of the bottom end of the expansion cone (41) is smaller than the inner diameter of the reduced diameter (200), and the outer diameter of the top end of the expansion cone (41) is larger than the inner diameter of the expansion sleeve (100).

3. The repair device for the reduced diameter of the expansion sleeve according to claim 1, characterized in that, The column anchoring assembly (2) further includes a column body (22), a second return spring (23), and a cover plate (24). The bottom end of the column body (22) is connected to the guide shoe (1), and the top end is connected to the pressure relief valve center pipe (31). The column body (22) is provided with a radial groove (221). The bottom of the radial groove (221) is provided with a second liquid inlet hole (222). The second liquid inlet hole (222) penetrates the side wall of the column body (22). The base end of the anchor claw (21) is placed in the radial groove (221) and covers the second liquid inlet hole. The anchoring end of the anchor claw (21) is provided with teeth and a long groove. A second return spring (23) is provided in the long groove. The second return spring (23) abuts against the cover plate (24). The cover plate (24) passes through the long groove and both ends of the cover plate (24) are fixed on the column body (22). The teeth are distributed on both sides of the long groove. When the anchor claw (21) extends radially, the long groove slides relative to the cover plate (24) and compresses the second return spring (23). The teeth are anchored to the expansion sleeve (100).

4. The repair device for the reduced diameter of the expansion sleeve according to claim 3, characterized in that, The bottom of the long groove is provided with a spring hole, and one end of the second reset spring (23) is located in the spring hole for limiting.

5. The repair device for the reduced diameter of the expansion sleeve according to claim 3, characterized in that, The anchor claw (21) is provided in at least three sets. The three sets of anchor claws (21) are spaced apart and staggered along the long axis of the column body (22). Each set includes at least three anchor claws (21). The at least three anchor claws (21) are spaced apart and evenly arranged along the circumferential direction of the column body (22).

6. The repair device for the reduced diameter of the expansion sleeve according to claim 3, characterized in that, The outer wall of the anchor claw (21) is provided with a circumferential annular groove, and a sealing ring (211) is provided in the annular groove. The sealing ring (211) is sandwiched between the anchor claw (21) and the radial groove (221).

7. The repair device for the reduced diameter of the expansion sleeve according to claim 1, characterized in that, The pressure relief valve center tube (31) is provided with multiple sealing grooves, and the multiple sealing grooves are respectively provided at the upper and lower ends of the pressure relief hole (311), and the sealing grooves are filled with vulcanized sealing strips (312).

8. The repair device for the reduced diameter of the expansion sleeve according to claim 1, characterized in that, The first liquid outlet (421) is provided in multiple ways, and the multiple first liquid outlets (421) are arranged at intervals along the axial and circumferential directions of the push sleeve (42).

9. A method for repairing a reduced diameter expansion sleeve, characterized in that, The expansion sleeve diameter reduction repair device according to any one of claims 1-8, the expansion sleeve diameter reduction repair method for repairing the diameter reduction (200) at the end of the expansion sleeve (100) includes the following steps: S1, the expansion casing diameter reduction repair device is lowered into the well at the diameter reduction (200) position of the expansion casing (100), the guide shoe (1) is inserted into the expansion casing (100), and it is lowered further until the cone surface (411) of the expansion cone (41) abuts the end of the diameter reduction (200); S2, a sealing ball (300) is placed into the repair device for the reduced diameter of the expansion sleeve. The sealing ball (300) falls into the ball seat (11) inside the guide shoe (1) and begins to pressurize. The anchor claw (21) of the pipe column anchoring assembly (2) extends radially under hydraulic action and anchors to the inner wall of the expansion sleeve (100). S3, continue to pressurize, the shear pin (551) on the end cap (55) is sheared off, the piston (54) pushes the expansion cone (41) downward along the axis, the cone surface (411) of the expansion cone (41) radially squeezes the reduced diameter (200), and the expansion sleeve (100) forms a flared mouth (400) at the reduced diameter (200); S4, when the expansion cone (41) moves downward, it pushes the push sleeve (42) downward. The push sleeve (42) pushes the pressure relief sleeve (32) downward and compresses the first return spring (33) until the top of the push sleeve (42) is lower than the pressure relief hole (311). The pressure relief hole (311) opens and the pressure drops suddenly, indicating that the diameter reduction (200) repair operation is completed. S5, the ground pump stops and the pressure is released. The pressure release sleeve (32) is reset under the elastic force of the first reset spring (33). The anchor claw (21) is retracted, the anchoring is released, and the expansion sleeve diameter reduction repair device is taken out.

10. The method for repairing the reduced diameter of an expansion sleeve according to claim 9, characterized in that, It also includes step S6, repeating steps S1-S5 to repair the reduced diameter (200) multiple times.

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