Packer supporting repeated release and tie-back, and operation method therefor

Abstract

A packer supporting repeated release and tie-back, and an operation method therefor. The packer supporting repeated release and tie-back comprises a center mechanism (1), a sealing locking mechanism (2), and a release / tie-back mechanism (3); the center mechanism (1) comprises a center pipe (11); a first hole (121) and a second hole (122) which are communicated with a cavity of the center pipe (11) are formed in a side wall of one end of the center pipe (11); the sealing locking mechanism (2) can enable the first hole (121) and the second hole (122) to be communicated with or separated from the cavity of the center pipe (11); the release / tie-back mechanism (3) is provided with a tie-back locking claw (331) and a support member; the support member is configured to be capable of being supported on the inner side of the tie-back locking claw (331) or enabling the tie-back locking claw (331) to disengage from the support member. When the packer is in use, the release / tie-back mechanism (3) is separated from the sealing locking mechanism (2), thereby avoiding affecting the normal use of the packer; when the position of the packer needs to be adjusted, the release / tie-back mechanism (3) is connected to the sealing locking mechanism (2), such that the packer is driven by the release / tie-back mechanism (3) to move to the next workstation, thereby avoiding the problem of frequent tripping, improving the construction efficiency.

Description

Repeatable tie-back packer and operation method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202310779537.1 filed on June 28, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of oilfield downhole tools, and in particular to a repeatable drop-out tie-back packer and an operating method thereof. Background Art

[0004] Currently, dual-seal, single-clamp tools are a mature tool technology widely used in stratified fracturing and production operations. In the dual-seal, single-clamp fracturing process, the spacing between the upper and lower packers is fixed and cannot be adjusted during a single string fracturing run. For perforation sections with varying intervals, frequent drilling and adjustment of the spacing between the two packers is required, resulting in low operation efficiency. In response to this, Chinese invention patent CN114458235A discloses a mechanically reusable bridge plug. This mechanically reusable bridge plug comprises a central assembly, an upper anchor assembly, upper and lower cone assemblies with a rubber seal, a lower friction anchor assembly, a reciprocating sliding locking assembly, and a salvage setting assembly. The salvage setting assembly includes a salvage tool upper connector, a recovery sleeve, and a guide shoe. The salvage tool upper connector is threadedly connected to the recovery sleeve and further secured with anti-rotation pins. The sidewalls of the recovery sleeve are machined with mounting grooves, bevel grooves, and recovery grooves. An insert tube is connected to the upper end of the bridge plug upper connector. A radially protruding pin is located on the upper portion of the insert tube. The pin switches between the mounting groove, bevel groove, and recovery groove to facilitate release and docking. It can be seen that the mechanically reusable bridge plug of this design can complete the release or docking by rotating the upper joint of the bridge plug so that the protruding pin switches in the installation groove, the inclined groove, and the recovery groove. However, this method of achieving release or docking by rotating the upper joint of the bridge plug is prone to operational errors, which may cause the upper joint of the bridge plug to accidentally detach from the insertion tube, posing a safety risk.

[0005] Summary of the Invention

[0006] In order to solve the technical problem that the traditional method of rotating the bridge plug upper joint to achieve release or docking is prone to operational errors, resulting in accidental detachment of the bridge plug upper joint and posing a safety risk, the present invention provides a repeatable release and tie-back packer and an operating method thereof.

[0007] The present invention provides a repeatable drop-out tie-back packer, comprising:

[0008] The central mechanism includes a central tube, wherein a side wall of one end of the central tube is provided with a first hole and a second hole communicating with the cavity of the central tube;

[0009] a sealing locking mechanism, a portion of which extends into the interior of the central tube, and the sealing locking mechanism is configured to be movable between an unsealing position and a sealing locking position, such that the sealing locking mechanism can connect or isolate the first hole and the second hole from the cavity of the central tube;

[0010] The drop-and-go reconnection mechanism comprises a reconnection claw with a locking hook that is clamped to the end of the sealing locking mechanism extending out of the central tube, and a support member that can limit the inward movement of the reconnection claw. The support member is configured to support the inner side of the reconnection claw or allow the reconnection claw to detach from the support member.

[0011] Optionally, the sealing and locking mechanism includes a joint, a limiting assembly, and a core shaft connected to the joint, wherein part of the core shaft extends into the interior of the central tube, and the joint can drive the core shaft to move between an unsealing position and a sealing and locking position, so that the core shaft connects or separates the first hole and the second hole from the cavity of the central tube, and the limiting assembly is configured to be able to limit or release the limit of the core shaft in the sealing and locking position.

[0012] Optionally, the limiting component includes:

[0013] A second limiting groove provided on the outer periphery of the core shaft; and

[0014] The core shaft locking claw is provided on the inner wall of the central tube and is configured as follows:

[0015] When the core shaft is in the sealing and locking position, the core shaft locking claw is engaged with the second limiting groove.

[0016] Optionally, an opening communicating with the cavity of the central tube is provided in the middle of the core shaft, a check valve is provided in the opening, and a bypass hole communicating with the opening is provided on the side wall of the central tube, and the configuration is as follows:

[0017] When the core shaft has not moved to the unsealing position, the bypass hole and the second hole are opposite to each other, and the first hole is connected to the cavity of the central tube;

[0018] When the core shaft moves to the sealing and locking position, the bypass hole and the second hole are positioned opposite to each other, and the core shaft blocks the end of the central tube to separate the first hole from the cavity of the central tube.

[0019] Optionally, a sealing packing is provided on the outer periphery of the end of the core shaft, and a core shaft valve seat is provided on the inner wall of the central tube. When the core shaft moves to the sealing locking position, the sealing packing fits against the inner wall of the core shaft valve seat to form a seal.

[0020] Optionally, the drop-and-go reconnection mechanism includes a support cylinder, a cylinder sleeved on the outer periphery of the support cylinder, and a limiting cylinder arranged between the cylinder body and the support cylinder, the reconnection locking claw is arranged at the end of the limiting cylinder, and the support member includes a control valve seat arranged at the end of the support cylinder, and the limiting cylinder is configured to be able to move along its axial direction so that the locking hook can be supported on the outer periphery of the control valve seat or detached from the control valve seat, and a first limiting groove matching the locking hook is provided inside the joint, and the length of the first limiting groove is greater than the length of the locking hook of the reconnection locking claw.

[0021] Optionally, the repeatable drop-back packer also includes an anchoring structure, which is arranged on the periphery of the central pipe and includes an anchoring member and a seating locking member. The anchoring member is configured to be supported on the inner wall of the sleeve or separated from the sleeve, and the seating locking member is configured to maintain the state of the anchoring member when the anchoring member is supported on the inner wall of the sleeve.

[0022] Optionally, the anchoring member includes a first anchoring member body, the first anchoring member body includes a seat body arranged on the outer periphery of the central tube, a plurality of mounting holes are provided on the seat body, a positioning anchor claw is provided inside the mounting hole, the positioning anchor claw is connected to the bottom wall of the mounting hole by an anchor claw reset spring, a first pressurizing hole is provided at a position of the seat body corresponding to the mounting hole, and a cover plate for pressing the positioning anchor claw is provided on the seat body.

[0023] Optionally, the anchoring member also includes a second anchoring member body, which includes a bushing sleeved on the outer periphery of the central tube and an upper rubber cylinder seat, a lower rubber cylinder seat and a rubber cylinder slidably sleeved on the outer periphery of the bushing, the upper rubber cylinder seat and the bushing are respectively connected to the seat body, and the rubber cylinder is arranged between the upper rubber cylinder seat and the lower rubber cylinder seat.

[0024] Optionally, the anchoring member also includes a third anchoring member body, which includes an upper cone and a lower cone arranged on the outer periphery of the central tube, and a cava arranged between the upper cone and the lower cone, the upper cone is connected to the lower rubber cylinder seat, and the outer peripheries of the upper cone and the lower cone are provided with a protective cover, the protective cover is provided with an opening at a position corresponding to the cava, and a first return spring is provided between the protective cover and the cava.

[0025] Optionally, the seating and locking member includes:

[0026] A rubber cylinder locking claw is connected to the bushing and is in sliding engagement with the inner wall of the upper cone;

[0027] The annular locking block is provided on the inner wall of the upper cone and is configured as follows:

[0028] When the rubber cylinder is in a compressed state, the rubber cylinder locking claw is engaged with the annular locking block to maintain the compressed state of the rubber cylinder.

[0029] Optionally, the third anchoring member body further includes a locking spring, and the locking spring is arranged between the protective sleeve and the lower rubber cylinder seat.

[0030] Optionally, the seating locking component further includes a slip ring, which is arranged on the outer periphery of the central tube, and the inner side of the slip ring is provided with a second slope surface matching the first slope surface of the rubber cylinder locking claw, so that when the rubber cylinder locking claw moves relative to the slip ring, the rubber cylinder locking claw can be retracted inward to disengage from the annular locking block.

[0031] Optionally, the repeatable tie-back packer further includes a track switching mechanism, which includes:

[0032] a track tube connected to an end of the center tube away from the tie-back mechanism, the track tube being provided with a plurality of setting grooves and unsealing grooves, the plurality of setting grooves and unsealing grooves forming a J-shaped track, the upper cone, the lower cone and the slips being arranged on the outer periphery of the track tube;

[0033] A switching ring is provided with a switching pin, wherein the switching ring and the switching pin are arranged in the J-shaped track and are configured as follows:

[0034] When the track tube is lifted, the switching ring can rotate so that the switching pin can switch between the setting groove and the unsealing groove.

[0035] Optionally, the repeatable drop-and-tie packer further comprises a righting mechanism, which is sleeved on the outer circumference of the trajectory tube and frictionally engaged with the inner wall of the sleeve.

[0036] Optionally, the righting mechanism includes:

[0037] a righting base, sleeved on the outer circumference of the track tube, the righting base being connected to the lower cone;

[0038] A plurality of straightening blocks are arranged on the straightening base at intervals along the circumferential direction of the central tube, and the straightening blocks extend out of the straightening base. A compression spring is provided between the straightening blocks and the straightening base.

[0039] Optionally, the repeatable tie-back packer further includes a reverse plugging valve mechanism, and the reverse plugging valve mechanism includes:

[0040] a sheath connected to an end of the track tube;

[0041] a lower connector connected to the sheath;

[0042] A reverse blocking valve seat is arranged inside the sheath, and the reverse blocking valve seat abuts against the lower joint;

[0043] The valve disc is mounted on the valve seat of the reverse blocking valve through a torsion spring.

[0044] Optionally, a lower connecting sleeve is provided on the outer periphery of the track tube, and two ends of the lower connecting sleeve are respectively connected to the straightening block base and the sleeve.

[0045] Optionally, a second pressurized hole is provided on the wall of the support cylinder, the limiting cylinder is configured to move in a direction away from the joint under a pressurized state, and a second return spring is provided between the limiting cylinder and the cylinder body.

[0046] The present invention also provides an operating method for a repeatable drop-and-tie packer, comprising the following steps:

[0047] The repeatable tie-back packer is lowered into the well. During the lowering of the tubing, the tie-back mechanism pushes the sealing locking mechanism downward, causing the sealing locking mechanism to move to the sealing locking position, isolating the cavity of the central pipe from the annulus between the packer and the casing.

[0048] Continue to lower the pipe string. When the pipe string reaches the preset position, the center pipe is supported on the inner wall of the sleeve.

[0049] Move the support to release the restriction on the tie-back claw, move the tie-back mechanism upward until the tie-back claw is disengaged from the sealing locking mechanism, move the upper tubing string, and the tie-back mechanism is separated from the sealing locking mechanism. The tie-back can be repeated to perform the corresponding operation;

[0050] After the operation is completed, the hand-dropping and reconnecting mechanism is lowered to connect the reconnecting locking claw with the sealing locking mechanism, and the support member is moved so that the support member is supported on the inner side of the reconnecting locking claw;

[0051] The tubing is lifted, and the tie-back mechanism drives the sealing locking mechanism to move to the unsealing position. The cavity of the central tube is connected to the first hole and the second hole, and the upper and lower pressures are balanced. The tubing is continued to be lifted, and the central tube is separated from the sleeve. Then, the repeatable tie-back packer is moved to the next working position by moving the tubing.

[0052] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0053] When the seal provided by the present invention is in use, the release and reconnection mechanism is separated from the sealing locking mechanism to avoid affecting the normal use of the seal. When it is necessary to adjust its own position, the release and reconnection mechanism can be connected to the sealing locking mechanism, so that the seal can be moved to the next working position under the drive of the release and reconnection mechanism, avoiding the problem of frequent drilling and improving construction efficiency. At the same time, the disassembly of the release and reconnection mechanism and the sealing locking mechanism of the present application requires actively applying a force toward the support member so that the support member can be separated from the inner side of the reconnection locking claw, preventing the release and reconnection mechanism from accidentally disengaging from the sealing locking mechanism, and ensuring the safety of construction. In addition, when the seal is in use, the sealing locking mechanism can always separate the first hole and the second hole from the cavity of the center pipe, and then separate the annulus between the seal and the casing from the cavity of the center pipe, ensuring the normal use of the seal. In addition, by lifting and lowering the tubing string to set the packer, and at the same time releasing the packer, and then lifting the tubing string to set the upper packer, the double-seal single-card fracturing method consisting of the upper and lower packers has the characteristic of no tubing connection between the upper and lower packers compared to the conventional double-seal single-card fracturing string. Therefore, it can avoid tubing erosion between the packers, and thus avoid complex downhole problems such as interlayer oil pipe breakage and perforation failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0056] FIG1 is a schematic structural diagram of a repeatable tie-back packer according to an embodiment of the present invention;

[0057] FIG2 is a schematic structural diagram of a portion of the repeatable tie-back packer in a set state according to an embodiment of the present invention;

[0058] FIG3 is a schematic structural diagram of the repeatable release tieback packer after release according to an embodiment of the present invention;

[0059] FIG4 is a schematic structural diagram of the repeatable tie-back packer in the first half of an embodiment of the present invention;

[0060] FIG5 is a schematic structural diagram of the repeatable tie-back packer in the lower half of the embodiment of the present invention;

[0061] FIG6 is a schematic structural diagram of a drop-and-reconnect mechanism according to an embodiment of the present invention;

[0062] FIG7 is a schematic structural diagram of a sealing locking mechanism according to an embodiment of the present invention;

[0063] FIG8 is a schematic structural diagram of the first anchoring member body according to an embodiment of the present invention;

[0064] FIG9 is a schematic structural diagram of the second anchoring member body according to an embodiment of the present invention;

[0065] FIG10 is a schematic structural diagram of the third anchoring member body according to an embodiment of the present invention;

[0066] FIG11 is a schematic structural diagram of a righting mechanism according to an embodiment of the present invention;

[0067] FIG12 is a schematic structural diagram of a track switching mechanism according to an embodiment of the present invention;

[0068] FIG13 is an expanded view of a J-shaped track of the track switching mechanism according to an embodiment of the present invention;

[0069] FIG14 is a schematic structural diagram of the reverse blocking valve mechanism according to an embodiment of the present invention.

[0070] Explanation of reference numerals 1. Central mechanism; 11. Central tube; 111. Core valve seat; 12. Upper connecting sleeve; 121. First hole; 122. Second hole; 2. Sealing locking mechanism; 21. Connector; 211. First limiting groove; 212. Guide groove; 22. Limiting assembly; 221. Second limiting groove; 222. Core locking claw; 23. Core; 231. Opening; 232. Check valve; 233. Sealing packing; 234. Valve plate; 235. Bypass hole; 3. Hand-off reconnection mechanism; 31. Support cylinder; 311. Control valve seat; 3111. Sealing rubber sleeve; 32. Cylinder; 33, limit cylinder; 331, return lock claw; 34, second return spring; 35, upper joint; 36, spring seat; 37, guide shoe; 38, first sealing ring; 39, second sealing ring; 4, anchoring structure; 41, anchoring member; 411, first anchoring member body; 4111, seat body; 4112, positioning anchor claw; 4113, anchor claw return spring; 4114, cover plate; 412, second anchoring structure Component body; 4121, bushing; 4122, upper rubber cylinder seat; 4123, lower rubber cylinder seat; 4124, rubber cylinder; 413, third anchoring member body; 4131, upper cone; 4132, lower cone; 4133, slip; 4134, protective cover; 4135, first return spring; 42, seat locking member; 421, rubber cylinder locking claw; 422, annular locking block; 423, locking spring; 424, Slip ring; 5. Track switching mechanism; 51. Track tube; 511. Sealing groove; 512. Unsealing groove; 52. Switching ring; 521. Switching pin; 6. Righting mechanism; 61. Righting base; 62. Righting block; 63. Compression spring; 64. Righting pressure ring; 7. Reverse sealing valve mechanism; 71. Sheath; 72. Lower joint; 73. Reverse sealing valve seat; 74. Valve disc; 75. Torsion spring; 8. Lower connecting sleeve. DETAILED DESCRIPTION

[0071] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0072] The following description sets forth many specific details to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the implementation methods in the specification are only part of the implementation methods of the present invention, not all of the implementation methods.

[0073] 1 to 5 , the repeatable tie-back packer provided in the embodiment of the present invention includes a central mechanism 1 , a sealing locking mechanism 2 and a tie-back mechanism 3 .

[0074] The central mechanism 1 includes a central tube 11, with a first hole 121 and a second hole 122 provided on the sidewall of one end of the central tube 11, which communicate with the cavity of the central tube 11. Specifically, an upper connecting sleeve 12 is provided at one end of the central tube 11, with the first hole 121 and the second hole 122 provided on the sidewall of the upper connecting sleeve 12. The central tube 11 has corresponding first and second ends. Taking the orientation shown in Figure 2 as an example, the first end of the central tube 11 is the left end of the central tube 11, and the second end of the central tube 11 is the right end of the central tube 11. The first end of the central tube 11 and the upper connecting sleeve 12 can be directly connected, or they can be indirectly connected by other mechanisms.

[0075] As shown in FIG4 , a portion of the sealing and locking mechanism 2 extends into the interior of the base pipe 11, and the sealing and locking mechanism 2 is configured to be movable between an unsealing position and a sealing and locking position, so that the sealing and locking mechanism 2 can connect or isolate the first hole 121 and the second hole 122 from the cavity of the base pipe 11, thereby isolating the annulus between the packer and the casing from the cavity of the base pipe 11. Specifically, a portion of the sealing and locking mechanism 2 extends into the interior of the upper connecting sleeve 12, and the sealing and locking mechanism 2 can move with the release and tie-back mechanism 3, so that the sealing and locking mechanism 2 can be driven by the release and tie-back mechanism 3 to move between the unsealing position and the sealing and locking position, and the sealing and locking mechanism 2 can remain in the unsealing position and the sealing and locking position.

[0076] The reconnection mechanism 3 includes a reconnection claw 331 with a locking hook that is snap-connected to one end of the sealing locking mechanism 2 extending from the central tube 11, and a support member capable of limiting the inward movement of the reconnection claw 331. The support member is configured to support the inner side of the reconnection claw 331 or allow the reconnection claw 331 to separate from the support member. Specifically, the support member can actively move, thereby actively separating from the reconnection claw 331 or supporting the inside of the reconnection claw 331.

[0077] When the seal provided by the present invention is in use, the release and reconnection mechanism 3 is separated from the sealing locking mechanism 2 to avoid affecting the normal use of the seal. When it is necessary to adjust its own position, the release and reconnection mechanism 3 can be connected to the sealing locking mechanism 2, so that the seal can be moved to the next working position under the drive of the release and reconnection mechanism 3, avoiding the problem of frequent drilling and improving construction efficiency. At the same time, the disassembly of the release and reconnection mechanism 3 and the sealing locking mechanism 2 of the present application requires actively applying a force toward the support member so that the support member can be separated from the inner side of the reconnection locking claw 331, preventing the release and reconnection mechanism 3 from being accidentally separated from the sealing locking mechanism 2, and ensuring the safety of construction. In addition, when the seal is in use, it can be separated from the cavity of the center pipe by the annulus between the seal and the casing to ensure the normal use of the seal. In addition, by lifting and lowering the tubing string to set the packer, and at the same time releasing the packer, and then lifting the tubing string to set the upper packer, the double-seal single-card fracturing method consisting of the upper and lower packers has the characteristic of no tubing connection between the upper and lower packers compared to the conventional double-seal single-card fracturing string. Therefore, it can avoid tubing erosion between the packers, and thus avoid complex downhole problems such as interlayer oil pipe breakage and perforation failure.

[0078] As shown in Figures 4 and 7 , the sealing and locking mechanism 2 includes a connector 21, a stopper assembly 22, and a mandrel 23 connected to the connector 21. A portion of the mandrel 23 extends into the interior of the central tube 11, specifically into the interior of the upper connecting sleeve 12. The connector 21 is capable of driving the mandrel 23 between an unsealing position and a sealing and locking position, such that the mandrel 23 connects or separates the first and second holes 121, 122 from the cavity of the central tube 11. The stopper assembly 22 is configured to restrict or release the mandrel 23 in the sealing and locking position. One end of the mandrel 23 extends into the connector 21 and is threadedly connected to the connector 21 to facilitate assembly and disassembly. The mandrel 23 can be further secured with a retaining screw to enhance the connection's strength. The other end of the mandrel 23 extends into the interior of the upper connecting sleeve 12, and the inserted end of the mandrel 23 is provided with a stepped surface. The upper connecting sleeve 12 is sleeved onto the stepped surface of the mandrel 23 to prevent the mandrel 23 from detaching from the upper connecting sleeve 12.

[0079] In some embodiments, as shown in FIG7 , the limiting assembly 22 includes a second limiting groove 221 disposed on the outer periphery of the core shaft 23 and a core shaft locking claw 222 disposed on the inner wall of the upper connecting sleeve 12 , wherein the second limiting groove 221 matches the core shaft locking claw 222. Specifically, the second limiting groove 221 is disposed on the outer periphery of the portion of the core shaft 23 that extends into the upper connecting sleeve 12 . When the core shaft 23 is in the sealed locked position, the core shaft locking claw 222 engages with the second limiting groove 221 . When the release reconnection mechanism 3 is lifted, the release reconnection mechanism 3 can drive the core shaft 23 upward via the joint 21, thereby separating the core shaft locking claw 222 from the core shaft 23 and unlocking the core shaft 23. This design of the limiting assembly 22 is simple in structure, and the separation or engagement process can be completed simply by lifting or lowering the release reconnection mechanism 3 , making operation convenient.

[0080] The middle part of the core shaft 23 is provided with an opening 231 connected to the cavity of the central tube 11, and a one-way valve 232 is provided in the opening 231 to provide one-way flow of the fluid. A bypass hole 235 connected to the opening 231 is provided on the side wall of the central tube (11), specifically, the bypass hole 235 is provided on the side wall of the upper connecting sleeve 12. When the core shaft 23 is not moved to the sealing locking position, the bypass hole 235 is opposite to the position of the second hole 122, and the first hole 121 is connected to the cavity of the central tube 11, and the upper and lower pressures are balanced. When the core shaft 23 moves to the sealing locking position, the bypass hole 235 is opposite to the position of the second hole 122, and the core shaft 23 blocks the end of the central tube 11 to separate the first hole 121 from the cavity of the central tube 11. The core shaft 23 under this design method occupies less space, making the overall structure more compact. Furthermore, whether in a sealed state or an unsealed state, it can be ensured that the positions of the first hole 121 or the second hole 122 and the bypass hole 235 completely correspond to each other, so as to maximize the flow rate of the fluid and meet the design requirements.

[0081] Further optimized, a sealing packing 233 is provided on the outer periphery of the end of the core shaft 23, and a core shaft valve seat 111 is provided on the inner wall of the center tube 11. When the core shaft 23 moves to the sealing locking position, the sealing packing 233 fits against the inner wall of the core shaft valve seat 111 to form a seal, thereby ensuring the tightness of the connection and the isolation effect. A packing lock cap is threadedly connected to the end of the core shaft 23, and the sealing packing 233 is sleeved on the outer periphery of the sealing packing 233 to increase the convenience of installing the sealing packing 233. The sealing packing 233 can be tightened by screwing the packing lock cap to ensure the fixing effect of the sealing packing 233. A tapered hole is provided inside the packing lock cap, and a check valve 232 is installed at the position of the tapered hole so that the check valve 232 is supported by the slope of the tapered hole. The function of the check valve 232 is to prevent the upper liquid from entering the lower part of the packer through the check valve 232 after the sealing locking mechanism 2 is sealed and locked.

[0082] For further optimization, a valve plate 234 may be provided inside the opening 231 of the core shaft 23. The valve plate 234 is supported on the inner wall of the core shaft 23 by the end of the packing lock cap to prevent the valve plate 234 from moving along the axial direction of the core shaft 23. The valve plate 234 is used to fix the valve ball of the check valve 232 to limit the valve ball in the tapered hole of the packing lock cap.

[0083] Among them, the first hole 121 and the second hole 122 are two holes opened on the side wall of the connecting sleeve 12. When the sealing locking mechanism 2 is in the locked state, as shown in Figure 2, the first hole 121 corresponds to the bypass hole 235 on the core shaft 23, connecting the inside and outside of the packer. When the sealing locking mechanism 2 is unlocked, that is, when the core shaft 23 is completely disengaged from the core shaft valve seat 111 described below, as shown in Figure 7, the second hole 122 completely corresponds to the opening 231 on the shaft, connecting the inside and outside of the packer. The first hole 121 and the second hole 122 have the same function, both serving as channels for reverse circulation of the packer. The two holes can ensure that no matter what operating conditions the core shaft 23 of the packer is in, one of the holes can be guaranteed to completely correspond to the bypass hole 235 on the core shaft 23, retaining the largest reverse circulation channel and minimizing the erosion of the core shaft 23 of the packer by liquid.

[0084] As shown in Figures 4 and 6 , the release and reconnection mechanism 3 includes a support tube 31, a cylinder body 32 sleeved around the outer periphery of the support tube 31, and a limiting tube 33 disposed between the cylinder body 32 and the support tube 31. The end of the support tube 31 extends beyond the cylinder body 32, and a limiting ring is provided on the outer periphery of the support tube 31 to limit the range of movement of the limiting tube 33 and prevent the limiting tube 33 from extending beyond the cylinder body 32. The reconnecting locking claw 331 is arranged at the end of the limiting cylinder 33, and the locking hook is arranged on the outside of the end of the reconnecting locking claw 331. The support member includes a control valve seat 311 arranged at the end of the support cylinder 31, and the diameter of the control valve seat 311 is larger than the diameter of the support cylinder 31. The limiting cylinder 33 is configured to be able to move along its axial direction so that the locking hook can be supported on the outer periphery of the control valve seat 311 or detached from the control valve seat 311. The interior of the joint 21 is provided with a first limiting groove 211 matching the locking hook, and the length of the first limiting groove 211 is greater than the length of the locking hook of the reconnecting locking claw 331.

[0085] Under normal conditions, the lock hook of the connection locking claw 331 is supported on the outer side of the control valve seat 311 to prevent the connection locking claw 331 from being retracted.

[0086] When the locking hook needs to be inserted into the first limiting groove 211, the limiting cylinder 33 needs to be moved in the direction away from the control valve seat 311 so that the locking hook is separated from the control valve seat 311. At this time, the reconnecting locking claw 331 is inserted into the connector 21. The reconnecting locking claw 331 can be retracted under the pressure of the connector 21 until the locking hook is inserted into the first limiting groove 211. The reconnecting locking claw 331 is unfolded and the limiting cylinder 33 is reset so that the locking hook is supported on the outer periphery of the control valve seat 311, avoiding accidental unlocking of the reconnecting locking claw 331 and ensuring safety of use.

[0087] When the release reconnection mechanism 3 needs to be disconnected from the connector 21, since the length of the first limiting groove 211 is greater than the length of the locking hook of the reconnection locking claw 331, the locking hook can move within the first limiting groove 211. By moving the limiting cylinder 33 away from the control valve seat 311, the locking hook is separated from the control valve seat 311 (the locking hook always remains in the first limiting groove 211). Then, by lifting the release reconnection mechanism 3, the locking hook is separated from the first limiting groove 211, completing the separation process of the release reconnection mechanism 3, which is convenient to operate.

[0088] As shown in Figures 1 to 3, the repeatable tie-back packer further includes an anchoring structure 4, which is disposed on the outer periphery of the central pipe 11 and includes an anchoring member 41 and a seating locking member 42. The anchoring member 41 is configured to be supported on the inner wall of the sleeve or to be separated from the sleeve, and the seating locking member 42 is configured to maintain the state of the anchoring member 41 when the anchoring member 41 is supported on the inner wall of the sleeve. When the packer is in the set state, the anchoring member 41 can be deployed by lowering the tubing string to support the inner wall of the sleeve. At this time, the seating locking member 42 can maintain the state of the anchoring member 41, ensuring the support effect of the anchoring member 41.

[0089] In some embodiments, as shown in FIG8 , the anchoring member 41 includes a first anchoring member body 411, which includes a seat 4111 disposed on the outer periphery of the base pipe 11. The seat 4111 is provided with a plurality of mounting holes, each of which includes a positioning anchor claw 4112 disposed within the mounting holes. The positioning anchor claw 4112 is connected to the bottom wall of the mounting hole via an anchor claw return spring 4113. The seat 4111 is provided with a first pressurizing hole at a position corresponding to the mounting hole, and the seat 4111 is provided with a cover plate 4114 for compressing the positioning anchor claw 4112. In the set state, pressure can be applied to the interior of the mounting hole through the first pressurizing hole. When the internal pressure of the positioning anchor claw 4112 is higher than the external pressure, that is, when the internal pressure of the packer is higher than the external pressure, the positioning anchor claw 4112 is activated and extends outward under the action of the internal and external pressure differential, anchoring the positioning anchor claw 4112 to the inner wall of the casing. In the unsealed state, positioning fluke 4112 can be reset by fluke reset spring 4113. The mounting holes can be blind holes, with six blind holes arranged in two rows and symmetrically distributed along the circumference of center tube 11. Positioning fluke 4112 and the outer arc surface of base 4111 are designed with grooves, and a cover plate 4114 is installed on the groove to compress positioning fluke 4112 and fluke reset spring 4113. Cover plate 4114 is fixed by tightening screws.

[0090] Specifically, the end of the seat body 4111 extends beyond the first end of the center tube 11, and the spindle valve seat 111 is threadedly connected to the inner wall of the extended end of the seat body 4111, increasing the convenience of assembly and disassembly. An O-ring for the spindle valve seat 111 is provided between the spindle valve seat 111 and the inner wall of the extended end of the seat body 4111 to ensure the tightness of the connection. The upper connecting sleeve 12 is threadedly connected to the outer periphery of the extended end of the seat body 4111, and a portion of the spindle locking claw 222 extends between the seat body 4111 and the upper connecting sleeve 12. The upper connecting sleeve 12, a portion of the spindle locking claw 222, and the extended end of the seat body 4111 are further tightened by anti-rotation screws to ensure the firmness of the connection.

[0091] In other embodiments, as shown in Figure 9, the anchoring member 41 also includes a second anchoring member body 412, which includes a sleeve 4121 sleeved on the outer circumference of the central pipe 11 and an upper rubber cylinder seat 4122, a lower rubber cylinder seat 4123 and a rubber cylinder 4124 slidably sleeved on the outer circumference of the sleeve 4121. The sleeve 4121 is clearance-matched with the central pipe 11 to form a hydraulic channel connected to the first pressurized hole. The hydraulic channel is connected to the lower part of the packer. The lower pressure of the packer is generally higher than the upper pressure of the packer. At this time, the internal pressure of the packer is introduced into the interior of the above-mentioned positioning anchor claw 4112. The outside of the positioning anchor claw 4112 is in the oil casing annulus above the packer, causing the internal pressure of the positioning anchor claw 4112 to be higher than the external pressure. The positioning anchor claw 4112 starts to extend to play the role of anchoring the pipe string. Among them, the positioning anchor claw 4112 is a conventional technology in this field, and therefore, its working principle is not described in detail.

[0092] It is worth noting that the third anchoring member body 413, described below, is activated when the packer is set. Upon activation, the third anchoring member body 413 prevents the tubing string from moving vertically. If the pressure below the packer is higher than the pressure above it, the first anchoring member body 411 activates, further preventing the tubing string from moving vertically. If the pressure below the packer is not higher than the pressure above it, the first anchoring member body 411 does not activate, and there is no other impact on the tubing string.

[0093] The upper rubber cylinder seat 4122 and the bushing 4121 are respectively connected to the seat body 4111. The rubber cylinder 4124 is arranged between the upper rubber cylinder seat 4122 and the lower rubber cylinder seat 4123, and the two ends of the rubber cylinder 4124 are respectively in close contact with the upper rubber cylinder seat 4122 and the lower rubber cylinder seat 4123. In this design, when the pipe string is lowered, the pipe string pushes the upper rubber cylinder seat 4122 and the bushing 4121 to move through the sealing lock and the first anchoring member body 411. At this time, because the rubber cylinder 4124 can be compressed, the bushing 4121 moves relative to the upper rubber cylinder seat 4122, the lower rubber cylinder seat 4123, and the rubber cylinder 4124. During this process, the rubber cylinder 4124 compresses and expands to support the inner wall of the sleeve, thus playing a positioning role.

[0094] Specifically, a partition plate is provided on one end of the seat body 4111 facing the adhesive cylinder seat 4122. A bushing 4121 is disposed on the inner side of the partition plate. The adhesive cylinder seat 4122 is wrapped around the outer side of the partition plate and is threadedly connected to the partition plate, increasing the convenience of assembly and disassembly. In addition, the inner ring of the adhesive cylinder seat 4122 extends out of the partition plate toward the inner side of the partition plate and is supported on the outer periphery of the bushing 4121. A gap is formed between the outer periphery of the bushing 4121 and the inner wall of the partition plate. An annular baffle is provided at the end of the bushing 4121. The annular baffle can slide within the gap and is limited in its range of movement by the inner ring of the adhesive cylinder seat 4122 to prevent excessive travel.

[0095] In other embodiments, as shown in FIG10 , the anchoring member 41 further includes a third anchoring member body 413, which includes an upper cone 4131, a lower cone 4132, and slips 4133 disposed on the periphery of the central pipe 11. The third anchoring member body 413 can be directly disposed on the periphery of the central pipe 11, or can be disposed on the periphery of the central pipe 11 via other structures. The upper cone 4131 is connected to the lower rubber cylinder seat 4123 so that the lower rubber cylinder seat 4123 can push the upper cone 4131 to move. A protective cover is provided on the outer periphery of the upper cone 4131 and the lower cone 4132. The protective cover is sleeved on the outer cross-section of the upper cone 4131 so that the protective cover can drive the upper cone 4131 to move downward. The protective cover is threadedly connected to the lower cone 4132. An opening is provided at the position corresponding to the protective cover and the slip 4133. A first return spring 4135 is provided between the protective cover and the slip 4133.

[0096] Specifically, the upper cone 4131 and the lower cone 4132 have slopes facing each other, and there are multiple slips 4133 installed on the outer circumference of the support mechanism (the track tube 51 described below). Slopes are also provided at the positions of the slips 4133 corresponding to the upper cone 4131 and the lower cone 4132, so that the contact surfaces between the slips 4133 and the upper cone 4131 and the lower cone 4132 are slopes. A first return spring 4135 is provided between the middle portion of the slip 4133 and the protective sleeve, and the first return spring 4135 is always in a compressed state to prevent the slips 4133 from prematurely activating during the lowering of the packer. During the lowering of the tubing string, the upper cone 4131 can be pushed by the lower rubber cylinder seat 4123. The slips 4133 move outward under the action of the slope to extend out of the opening, and the slips 4133 are supported on the inner wall of the sleeve, which has a limiting effect. After the external force disappears, the slip 4133 is retracted into the interior of the protective sleeve 4134 under the action of the first return spring 4135 to contact the limit position. At this time, the upper cone 4131 is reset.

[0097] As further optimized, as shown in FIG9 , the third anchoring member body 413 further includes a locking spring 423, which is disposed between the protective sleeve 4134 and the lower rubber cylinder seat 4123 and is sleeved around the outer circumference of the upper cone 4131. When the third anchoring member body 413 is anchored, the lower cone 4132 moves upward, driving the protective sleeve 4134 to compress the locking spring 423. Therefore, the locking spring 423 remains compressed during the anchoring of the third anchoring member body 413. When the packer is raised, the tubing string drives the upper cone 4131 upward, while the locking spring 423 pushes the protective sleeve 4134 downward, which in turn drives the lower cone 4132 downward. Consequently, the upper cone 4131 moves upward, while the lower cone 4132 moves downward. The slips 4133, activated by the first return spring 4135, return to their original state, releasing the anchoring state.

[0098] The anchoring member 41 of the present application includes a first anchoring member body 411, a second anchoring member body 412, and a third anchoring member body 413, which are distributed at the upper and lower positions of the repeatable release tieback packer. This ensures that the repeatable release tieback packer is evenly stressed, ensuring the setting effect of the repeatable release tieback packer and ensuring that the packer withstands both downward and upward pressure during use. In other words, after the packer is set, the rubber sleeve 4124 seals the annulus between the tubing string and the casing, and the mandrel 23 inside the packer seals the internal annulus of the tubing string. Therefore, after the packer is set, a barrier is formed to prevent communication between the upper and lower parts of the packer.

[0099] In some embodiments, as shown in FIG9 , the locking member 42 includes a rubber cartridge locking claw 421 and an annular locking block 422. The rubber cartridge locking claw 421 is connected to the bushing 4121 and slidably engages with the inner wall of the upper cone 4131. The annular locking block 422 is disposed on the inner wall of the upper cone 4131. When the rubber cartridge 4124 is in a compressed state, the rubber cartridge locking claw 421 and the annular locking block 422 engage, thereby maintaining the compressed state of the rubber cartridge 4124.

[0100] Specifically, the end of the cartridge locking claw 421 is threadedly connected to the outer periphery of the end of the bushing 4121 to facilitate assembly and disassembly. The inner wall of the lower cartridge seat 4123 is machined with double steps to accommodate the end of the cartridge locking claw 421 and the end of the upper cone 4131, respectively, making the structure more compact. The locking hook of the cartridge locking claw 421 faces outward and is able to slide relative to the inner wall of the upper cone 4131. The end of the locking hook of the cartridge locking claw 421 is provided with a sloped surface. When the locking hook of the cartridge locking claw 421 contacts the inner wall of the annular locking block 422 during movement of the cartridge locking claw 421 relative to the inner wall of the upper cone 4131, the cartridge locking claw 421 is guided inward by the sloped surface, allowing it to move to the other side of the annular locking block 422, thereby achieving a locking engagement between the cartridge locking claw 421 and the annular locking block 422. With this design, when the rubber cylinder 4124 is in a compressed state and the release and reconnection mechanism 3 is disengaged, the rubber cylinder locking claw 421 and the annular locking block 422 can cooperate to prevent the rubber cylinder 4124 from resetting, thereby ensuring the anchoring effect of the rubber cylinder 4124 and thus ensuring safe construction.

[0101] For further optimization, the seating locking component 42 also includes a slip ring 424, which is arranged on the outer periphery of the central tube 11. The inner side of the slip ring 424 is provided with a second slope surface that matches the first slope surface of the rubber cylinder locking claw 421, so that during the movement of the rubber cylinder locking claw 421 relative to the slip ring 424, the rubber cylinder locking claw 421 can be retracted to disengage from the annular locking block 422.

[0102] Specifically, when unsealing is required, the pipe column is lifted. Due to the clamping connection between the rubber cylinder locking claw 421 and the annular locking block 422, the slip ring 424 on the central pipe 11 has an upward movement tendency, thereby pushing the rubber cylinder locking claw 421 inward through the cooperation of the first slope surface and the second slope surface, so that the rubber cylinder locking claw 421 and the annular locking block 422 are actively disengaged, thereby reducing the damage caused by the hard contact between the rubber cylinder locking claw 421 and the annular locking block 422, and ensuring the service life of the rubber cylinder locking claw 421 and the annular locking block 422.

[0103] The annular space between the tubing string exterior and the casing interior is sealed by a rubber sleeve 4124, while the interior of the packer is sealed by a mandrel 23, resulting in reliable sealing performance. The inner and outer seals are locked by a stopper assembly 22 and a locking member 42, respectively, ensuring that the packer will not be accidentally unlocked and lost during the sealing process. In other words, once the inner and outer seals are established, the packer acts like a set bridge plug, isolating the lower well section while allowing operations to proceed in the upper well section isolated by the packer.

[0104] As shown in Figures 12 and 13 , the repeatable release and tie-back packer of the present application also includes a track switching mechanism 5, which includes a track tube 51 and a switching ring 52. The track tube 51 is threadedly connected to the end of the central tube 11 away from the release and tie-back mechanism 3 to increase the convenience of disassembly and assembly. The track tube 51 is provided with a plurality of setting grooves 511 and unsealing grooves 512, wherein the length of the setting grooves 511 is greater than the length of the unsealing grooves 512. The plurality of setting grooves 511 and unsealing grooves 512 form a J-shaped track. The upper cone 4131, the lower cone 4132, and the slips 4133 are arranged on the outer periphery of the track tube 51 to make the overall structure more compact. A switching pin 521 is provided on the switching ring 52, wherein the switching ring 52 is processed with two symmetrically distributed through holes along the radial direction. There are two switching pins 521, and the two switching pins 521 are respectively arranged in the two through holes. The switching ring 52 and the switching pin 521 are arranged in a J-shaped track, and when the track tube 51 is lifted, the switching ring 52 can rotate so that the switching pin 521 can switch between the sealing groove 511 and the unsealing groove 512.

[0105] As shown in FIG11 , the repeatable release tieback packer of the present application also includes a centering mechanism 6, which is sleeved around the outer periphery of the track tube 51 and frictionally engaged with the inner wall of the sleeve. The centering mechanism 6 is used to ensure that the packer is in a centering state in the wellbore and, at the same time, provides a certain amount of friction to prevent the packer from being lowered too quickly.

[0106] In some embodiments, the straightening mechanism 6 includes a straightening base 61 and a plurality of straightening blocks 62. The straightening base 61 is sleeved on the outer circumference of the track tube 51 and is threadedly connected to the lower cone 4132. A plurality of straightening blocks 62 are arranged on the straightening base 61 at intervals along the circumferential direction of the center tube 11, and the straightening blocks 62 extend out of the straightening base 61. A compression spring 63 is provided between the straightening block 62 and the straightening base 61 to push the straightening block 62 out of the straightening base 61 through the compression spring 63. The straightening block 62 is always in an extended state under the support of the preload force provided by the compression spring 63, so that the straightening block 62 can be supported on the inner wall of the sleeve. Among them, a plurality of blind holes are opened on the straightening block 62, and some of the compression springs 63 are located in the blind holes to limit the compression spring 63 through the blind holes and limit the compression direction of the compression spring 63. The elastic force of the compression spring 63 can be designed according to actual needs.

[0107] For further optimization, the straightening mechanism 6 also includes a straightening pressure ring 64, which is sleeved on the outer periphery of the track tube 51, and the end of the straightening pressure ring 64 is threadedly connected to the straightening base 61, and the end of the straightening pressure ring 64 extends into the straightening base 61, so that the end of the straightening pressure ring 64 can be pressed on one side edge of the straightening block 62, and a pressure plate is provided at a position of the straightening base 61 corresponding to the other side edge of the straightening block 62. Accordingly, bosses are provided at both ends of the straightening block 62, and the two bosses are in contact with the end of the straightening pressure ring 64 and the pressure plate respectively to ensure the limiting effect of the straightening block 62, prevent the straightening block 62 from being separated from the straightening base 61, and the compression spring 63 is in a compressed state in the straightening base 61. By providing the straightening pressure ring 64, the components of the straightening mechanism 6 are designed separately, which increases the convenience of disassembly and processing.

[0108] As shown in FIG14 , the repeatable releasable tie-back packer of the present application further includes a reverse blocking valve mechanism 7, which includes a sheath 71, a lower connector 72, a reverse blocking valve seat 73, and a valve flap 74. The sheath 71 is connected to the end of the track tube 51. The lower connector 72 is connected to the sheath 71. The reverse blocking valve seat 73 is disposed within the sheath 71 and abuts against the lower connector 72. The valve flap 74 is mounted on the reverse blocking valve seat 73 via a torsion spring 75.

[0109] Specifically, the inner wall of the sheath 71 is machined with a stepped surface, and the reverse blocking valve seat 73 is installed inside the sheath 71, and the upper end of the reverse blocking valve seat 73 contacts the stepped surface of the inner wall of the sheath 71. A reverse blocking valve O-ring is installed between the reverse blocking valve seat 73 and the sheath 71 to ensure the tightness of the connection. The lower end surface of the reverse blocking valve seat 73 contacts the upper end surface of the lower joint 72, and the lower joint 72 is threadedly connected to the sheath 71. The reverse blocking valve seat 73 is installed with a valve disc 74, and the reverse blocking valve seat 73 and the valve disc 74 are connected by a torsion spring 75.

[0110] When in use, the valve flap 74 is generally in an open state under the spring force of the torsion spring 75. When the liquid pressure at the bottom of the packer is higher than the upper pressure, the valve flap 74 overcomes the spring force of the torsion spring 75 under the action of the pressure difference, and the valve flap 74 rotates 90° to contact the valve seat 73 to form a blocked state. At this time, the valve flap 74 of the reverse blocking valve mechanism 7 is subjected to the force of the liquid at the bottom of the packer, and the force is transmitted by the reverse blocking valve mechanism 7 to the sheath 71 connected thereto, and then the force is continued to be transmitted to the lower cone 4132, further squeezing the cava 4133 to assist the third anchoring member body 413.

[0111] As a further optimization, a lower connecting sleeve 8 is provided on the outer periphery of the track tube 51. Its two ends are respectively connected to the base of the centralizing block 62 and the protective sleeve 71, enhancing the connection security and structural compactness. Specifically, one end of the lower connecting sleeve 8 is threadedly connected to the pressure ring of the centralizing block 62, while the other end of the lower connecting sleeve 8 is threadedly connected to the protective sleeve 71. The lower connecting sleeve 8 compresses the end face of the switching ring 52, ensuring that the switching ring 52 moves along the J-shaped track.

[0112] In some embodiments, a second pressurized hole is provided on the wall of the support cylinder 31 , the limiting cylinder 33 is configured to move in a direction away from the joint 21 under pressurized conditions, and a second return spring 34 is provided between the limiting cylinder 33 and the cylinder body 32 .

[0113] Specifically, an annular push plate is provided at the end of the limiting cylinder 33 that extends between the support cylinder 31 and the cylinder body 32. A first sealing ring 38 is provided between the annular push plate and the outer periphery of the support cylinder 31. A second sealing ring 39 is provided on the side of the second pressurization hole away from the first sealing ring 38. This creates a pressure injection space between the first and second sealing rings 38 and 39 that communicates with the second pressurization hole. When pressure is injected into the pressure injection space, the pressure pushes the annular push plate away from the connector 21, causing the reconnection pawl 331 to disengage from the control valve seat 311. When the disconnect mechanism 3 is disconnected from the connector 21, pressure injection ceases, and the reconnection pawl 331 is reset by the second return spring 34. This design allows the reconnection pawl 331 to disengage from the control valve seat 311 through pressure, preventing misoperation and effectively ensuring construction safety.

[0114] Specifically, the release tieback mechanism 3 of the present application also includes an upper joint 35 connected to the tubular column. The barrel 32 is threadedly connected to the outer wall of the upper joint 35, and the support barrel 31 is threadedly connected to the inner wall of the upper joint 35. A spring seat 36 is installed in the annular space formed between the barrel 32 and the support barrel 31. A second return spring 34 and a portion of the tieback pawl 331 are located in the annular space, and the second return spring 34 is connected to the spring seat 36. A guide shoe 37 is threadedly connected to the end of the barrel 32, which is used to control the extension length of the tieback pawl 331. A sealing rubber sleeve 3111 is provided on the outer periphery of the control valve seat 311 to enhance the tightness of the connection between the control valve seat 311 and the joint 21.

[0115] It is understandable that sealing rings can be reasonably provided between the components that need to be sealed in this application to ensure a sealed connection between the corresponding components.

[0116] The end of the connector 21 of the present application is provided with a guide groove 212. The guide groove 212 is open and connected to the first limiting groove 211 via a transition groove. When the reconnecting locking claw 331 is inserted into the connector 21, the reconnecting locking claw 331 is preferentially inwardly moved by the guide groove 212, so that the locking hook of the reconnecting locking claw 331 can be inserted into the first limiting groove 211, thereby increasing the convenience of inserting the reconnecting locking claw 331. In addition, the side walls of the first limiting groove 211 are provided with slopes at both ends to facilitate the locking hook to disengage from the first limiting groove 211.

[0117] The present invention also provides a method for operating the above-mentioned repeatable tie-back packer, comprising the following steps:

[0118] Step S1, lower the repeatable release and tie-back packer into the well. During the lowering of the tubing string, the release and tie-back mechanism 3 pushes the sealing locking mechanism 2 downward, so that the sealing locking mechanism 2 moves to the sealing locking position, isolating the cavity of the central pipe 11 from the annulus between the packer and the casing.

[0119] Specifically, during the string's lowering, due to friction between the centering mechanism 6 and the inner wall of the casing, the packer's connector 21 pushes the mandrel 23 downward. Mandrel 23 contacts the mandrel valve seat 111, forming a seal that isolates the central pipe 11 cavity from the annulus between the packer and casing. The mandrel locking claw 222 locks with the second stopper groove 221 on the mandrel 23, activating the seal locking mechanism 2.

[0120] Step S2: Continue lowering the pipe string. When the pipe string is lowered to the preset position, the center pipe is supported on the inner wall of the sleeve. At this time, the anchoring member 41 works, so that the anchoring member 41 is supported on the inner wall of the sleeve, and the anchoring member 41 is maintained in this state by the locking member 42.

[0121] Specifically, the tubing string is continuously lowered, and the tubing string overcomes the friction between the straightening mechanism 6 and the inner wall of the sleeve and is lowered into the designed position. The tubing string is lifted to switch the track switching mechanism 5 of the packer to the packer setting track (the switching pin 521 slides into the setting groove 511). The tubing string is lowered. Due to the friction between the straightening mechanism 6 and the inner wall of the sleeve, the lower cone 4132 threadedly connected to the straightening mechanism 6 is fixed when the tubing string is lowered, and the upper part of the straightening mechanism 6 moves downward, that is, the upper cone 4131 moves downward, and the slip 4133 is squeezed out of the protective sleeve and anchored on the sleeve, and the anchoring mechanism function at the bottom is activated. The tubing string continues to be lowered, and the rubber sleeve 4124 is compressed to form a seal with the inner wall of the sleeve. The rubber sleeve locking claw 421 is engaged with the annular locking block 422, and the locking function of the setting locking component 42 is activated, and the packer is set. The structural form of the setting locking component 42 has been described above and will not be explained in detail here.

[0122] Step S3, move the support to release the restriction on the tie-back locking claw 331, move the release tie-back mechanism 3 upward until the tie-back locking claw 331 is separated from the sealing locking mechanism 2, and the upper body pipe string is installed. The release tie-back mechanism 3 is separated from the sealing locking mechanism 2, and the release tie-back packer can be repeated to perform the corresponding operation.

[0123] Specifically, liquid is pumped into the tubing to apply pressure, and the limit cylinder 33 moves upward under the action of the liquid pressure. A steel ball of appropriate size is thrown into the tubing, and the steel ball sits on the conical surface of the control valve seat 311, forming a seal with the control valve seat 311. Pressure is pumped into the tubing from the wellhead, and the pressure enters the injection space through the channel in the support cylinder 31 and the second pressurized hole. The resulting pressure difference pushes the reconnection claw 331 upward and pushes the support cylinder 31 downward, so that the reconnection claw 331 is separated from the support cylinder 31, and the forced lock between the reconnection claw 331 and the joint 21 is released. At this time, the internal pressure of the release reconnection mechanism 3 pushes the reconnection claw 331 upward, and the lock between the reconnection claw 331 and a limit groove is completely released. Continue to lift the tubing, and the tubing drives the entire release reconnection mechanism 3 upward, and the release reconnection mechanism 3 is separated from the joint 21, and the packer is released successfully. When the release and reconnection mechanism 3 is disengaged, the reconnection locking claw 331 and the support tube 31 return to their original positions under the action of the spring force of the second return spring 34 .

[0124] Step S4 , after the operation is completed, the hand-dropping and reconnecting mechanism 3 is lowered to connect the reconnecting locking claw 331 with the sealing locking mechanism 2 , and the support member is moved so that the support member is supported on the inner side of the reconnecting locking claw 331 .

[0125] Specifically, the hand-release tie-back mechanism 3 is lowered to the setting position of the packer, the hand-release tie-back mechanism 3 is lowered, and the tie-back locking claw 331 and the inner wall of the joint 21 form an extrusion stop action, and the hand-release tie-back mechanism 3 is continued to be pressed down, and the tie-back locking claw 331 is retracted under force and disengaged from the support tube 31. After the support tube 31 is lowered into the interior of the joint 21, when the support tube 31 is completely separated from the reconnecting locking claw 331, the reconnecting locking claw 331 contracts inwardly under the action of the downward pressure of the tubing, and the overall outer diameter of the reconnecting locking claw 331 is reduced. The tubing continues to descend, and the retracted reconnecting locking claw 331 passes through the inner wall of the joint 21 and enters the first limiting groove 211. After the reconnecting locking claw 331 enters the interior of the first limiting groove 211, under the spring force of the second reset spring 34, the support tube 31 returns to its original position, and the support tube 31 and the reconnecting locking claw 331 form a forced lock again to prevent the reconnecting locking claw 331 from being accidentally unlocked from the joint 21, and the reconnection of the hand-release reconnection mechanism 3 and the packer is completed.

[0126] In step S5, the tubing is lifted, and the re-tie mechanism 3 drives the sealing locking mechanism 2 to move to the unsealing position. The cavity of the central tube 11 is connected with the first hole 121 and the second hole 122. The upper and lower pressures are balanced, and the tubing is continued to be lifted. The central tube 11 is separated from the sleeve, and then the repeatable re-tie packer is moved to the next working position by moving the tubing.

[0127] Specifically, the tubing is lifted, and the limit assembly 22 is first unlocked and disengaged under a relatively small force, so that the upper and lower annuli of the packer are connected, and the upper and lower pressures are balanced (the tubing is lowered to seal the packer, and the rubber cylinder 4124 is compressed and sealed, sealing the oil casing annulus outside the packer, and the core shaft 23 inside the packer is sealed and locked with the core shaft valve seat 111. A one-way valve 232 is provided inside the core shaft 23, and the liquid in the annulus outside the packer cannot enter below the packer through the first hole 121 and the second hole 122. The tubing is lifted to unseal the packer, and the seal between the core shaft 23 inside the packer and the core shaft valve seat 111 is first unlocked, and the liquid in the upper part of the packer can be connected with the space in the lower part of the packer through the first hole 121 and the second hole 122, so that the upper pressure of the rubber cylinder 4124 is balanced with the lower pressure of the packer, preventing the packer from encountering resistance when being lifted), and the anchor claw is recovered under the action of the reset spring. Continue lifting the string. Slip ring 424 compresses the rubber sleeve locking claw 421, forcibly retracting it. The lock between the rubber sleeve locking claw 421 and the upper cone 4131 is released, and the upper anchoring mechanism is released. As the string moves upward, the rubber sleeve 4124 is released from compression, the upper cone 4131 moves upward, and the slips 4133 are retracted by the first return spring 4135. The lower anchoring mechanism is released, and the packer is released. Continue lifting and dragging the string to the next designed position. Repeating these steps can achieve multiple movement of the string.

[0128] In addition, after the packer is set and released, the effectiveness of the packer seal can be verified by pressurizing the tubing string to ensure the sealing effect.

[0129] The present application can effectively solve the problem of frequent drilling to adjust the distance between the two packers and severe erosion of the tubing between the two packers in the double-seal single-strap fracturing process, and realize the free-strap distance double-seal single-strap fracturing process technology without interlayer connected oil pipes, effectively improving the efficiency of on-site construction operations.

[0130] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0131] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments described herein, but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

Claims

1. A repeatable tie-back packer, characterized in that: include: A central mechanism (1) comprises a central tube (11), wherein a first hole (121) and a second hole (122) communicating with a cavity of the central tube (11) are provided on a side wall at one end of the central tube (11); a sealing locking mechanism (2), wherein a portion of the sealing locking mechanism (2) extends into the interior of the central tube (11), and the sealing locking mechanism (2) is configured to be movable between an unsealing position and a sealing locking position, so that the sealing locking mechanism (2) can connect or separate the first hole (121) and the second hole (122) from the cavity of the central tube (11); The hand-dropping reconnection mechanism (3) comprises a reconnection locking claw (331) with a locking hook which is clamped and connected to one end of the sealing locking mechanism (2) extending out of the central tube (11), and a support member capable of limiting the inward movement of the reconnection locking claw (331), wherein the support member is configured to be able to support the inner side of the reconnection locking claw (331) or to allow the reconnection locking claw (331) to be separated from the support member.

2. The repeatable tie-back packer according to claim 1, characterized in that: The sealing locking mechanism (2) comprises a joint (21), a limiting assembly (22) and a core shaft (23) connected to the joint (21); a portion of the core shaft (23) extends into the interior of the central tube (11); the joint (21) can drive the core shaft (23) to move between an unsealing position and a sealing locking position, so that the core shaft (23) connects or separates the first hole (121) and the second hole (122) from the cavity of the central tube (11); and the limiting assembly (22) is configured to limit or release the limit of the core shaft (23) in the sealing locking position.

3. The repeatable tie-back packer according to claim 2, characterized in that: The limiting component (22) comprises: A second limiting groove (221) is arranged on the outer periphery of the core shaft (23); and The mandrel locking claw (222) is arranged on the inner wall of the central tube (11) and is configured as follows: When the core shaft (23) is in the sealing and locking position, the core shaft locking claw (222) is engaged with the second limiting groove (221).

4. The repeatable tie-back packer according to claim 2, characterized in that: The central part of the core shaft (23) is provided with an opening (231) communicating with the cavity of the central tube (11), a check valve (232) is provided in the opening (231), and a bypass hole (235) communicating with the opening (231) is provided on the side wall of the central tube (11), and the configuration is as follows: When the core shaft (23) has not moved to the unsealing position, the bypass hole (235) is located opposite to the second hole (122), and the first hole (121) is connected to the cavity of the central tube (11); When the core shaft (23) moves to the sealing locking position, the bypass hole (235) and the second hole (122) are positioned opposite each other, and the core shaft (23) blocks the end of the central tube (11) to separate the first hole (121) from the cavity of the central tube (11).

5. The repeatable tie-back packer according to claim 4, characterized in that: A sealing packing (233) is provided on the outer periphery of the end of the core shaft (23), and a core shaft valve seat (111) is provided on the inner wall of the center tube (11); when the core shaft (23) moves to a sealing locking position, the sealing packing (233) fits against the inner wall of the core shaft valve seat (111) to form a seal.

6. The repeatable tie-back packer according to claim 2, characterized in that: The hand-dropping reconnection mechanism (3) comprises a support cylinder (31), a cylinder body (32) sleeved on the outer periphery of the support cylinder (31), and a limiting cylinder (33) arranged between the cylinder body (32) and the support cylinder (31); the reconnection locking claw (331) is arranged at the end of the limiting cylinder (33); the support member comprises a control valve seat (311) arranged at the end of the support cylinder (31); the limiting cylinder (33) is configured to be movable along its axial direction so that the locking hook can be supported on the outer periphery of the control valve seat (311) or detached from the control valve seat (311); a first limiting groove (211) matching the locking hook is provided inside the joint (21), and the length of the first limiting groove (211) is greater than the length of the locking hook of the reconnection locking claw (331).

7. The repeatable tie-back packer according to claim 1, characterized in that: The repeatable drop-back packer also includes an anchoring structure (4), which is arranged on the outer periphery of the central pipe (11), and includes an anchoring member (41) and a seating locking member (42). The anchoring member (41) is configured to be supported on the inner wall of the sleeve, or to be separated from the sleeve, and the seating locking member (42) is configured to maintain the state of the anchoring member (41) when the anchoring member (41) is supported on the inner wall of the sleeve.

8. The repeatable tie-back packer according to claim 7, characterized in that: The anchoring member (41) comprises a first anchoring member body (411), the first anchoring member body (411) comprising a seat body (4111) arranged on the outer periphery of the central tube (11), the seat body (4111) being provided with a plurality of mounting holes, a positioning anchor claw (4112) being provided inside the mounting hole, the positioning anchor claw (4112) being connected to the bottom wall of the mounting hole via an anchor claw reset spring (4113), a first pressurizing hole being provided at a position of the seat body (4111) corresponding to the mounting hole, and a cover plate (4114) for pressing the positioning anchor claw (4112) being provided on the seat body (4111).

9. The repeatable tie-back packer according to claim 8, characterized in that: The anchoring member (41) also includes a second anchoring member body (412), which includes a bushing (4121) sleeved on the outer periphery of the central tube (11), and an upper rubber cylinder seat (4122), a lower rubber cylinder seat (4123) and a rubber cylinder (4124) slidably sleeved on the outer periphery of the bushing (4121), the upper rubber cylinder seat (4122) and the bushing (4121) are respectively connected to the seat body (4111), and the rubber cylinder (4124) is arranged between the upper rubber cylinder seat (4122) and the lower rubber cylinder seat (4123).

10. The repeatable tie-back packer according to claim 9, characterized in that: The anchoring member (41) also includes a third anchoring member body (413), which includes an upper cone (4131) and a lower cone (4132) arranged on the outer periphery of the central tube (11), and a slip (4133) arranged between the upper cone (4131) and the lower cone (4132), wherein the upper cone (4131) is connected to the lower rubber cylinder seat (4123), and a protective sleeve (4134) is provided on the outer periphery of the upper cone (4131) and the lower cone (4132), and an opening is provided at a position corresponding to the protective sleeve (4134) and the slip (4133), and a first return spring (4135) is provided between the protective sleeve (4134) and the slip (4133).

11. The repeatable tie-back packer according to claim 10, characterized in that: The seating locking member (42) comprises: a rubber cylinder locking claw (421) connected to the bushing (4121), and the rubber cylinder locking claw (421) is slidably matched with the inner wall of the upper cone (4131); The annular locking block (422) is arranged on the inner wall of the upper cone (4131) and is configured as follows: When the rubber cylinder (4124) is in a compressed state, the rubber cylinder locking claw (421) is engaged with the annular locking block (422) so as to maintain the compressed state of the rubber cylinder (4124).

12. The repeatable tie-back packer according to claim 10, characterized in that: The third anchoring member body (413) further includes a locking spring (423), and the locking spring (423) is arranged between the protective sleeve (4134) and the lower rubber cylinder seat (4123).

13. The repeatable tie-back packer according to claim 11, characterized in that: The seating locking member (42) further comprises a slip ring (424) which is arranged on the outer periphery of the central tube (11), and the inner side of the slip ring (424) is provided with a second slope surface which matches the first slope surface of the rubber cylinder locking claw (421), so that when the rubber cylinder locking claw (421) moves relative to the slip ring (424), the rubber cylinder locking claw (421) can be moved inward to disengage from the annular locking block (422).

14. The repeatable tie-back packer according to claim 10, characterized in that: The repeatable drop-and-tie packer further comprises a track switching mechanism (5), and the track switching mechanism (5) comprises: A track tube (51) is connected to an end of the center tube (11) away from the hand-release tie-back mechanism (3); a plurality of setting grooves (511) and unsealing grooves (512) are provided on the track tube (51); the plurality of setting grooves (511) and unsealing grooves (512) form a J-shaped track; the upper cone (4131), the lower cone (4132) and the slips (4133) are arranged on the outer periphery of the track tube (51); The switching ring (52) is provided with a switching pin (521), and the switching ring (52) and the switching pin (521) are arranged in the J-shaped track and are configured as follows: When the track tube (51) is lifted up, the switching ring (52) can rotate so that the switching pin (521) can switch between the setting groove (511) and the unsealing groove (512).

15. The repeatable tie-back packer according to claim 14, characterized in that: The repeatable drop-and-tie packer further comprises a straightening mechanism (6), wherein the straightening mechanism (6) is sleeved on the outer circumference of the track tube (51), and the straightening mechanism (6) is frictionally matched with the inner wall of the sleeve.

16. The repeatable tie-back packer according to claim 15, characterized in that: The straightening mechanism (6) comprises: A righting base (61) is sleeved on the outer circumference of the track tube (51), and the righting base (61) is connected to the lower cone (4132); A plurality of straightening blocks (62) are arranged on the straightening base (61) at intervals along the circumferential direction of the central tube (11), and the straightening blocks (62) extend out of the straightening base (61). A compression spring (63) is provided between the straightening blocks (62) and the straightening base (61).

17. The repeatable tie-back packer according to claim 16, characterized in that: The repeatable drop-out tie-back packer further comprises a reverse plugging valve mechanism (7), and the reverse plugging valve mechanism (7) comprises: A sheath (71) connected to the end of the track tube (51); A lower connector (72) connected to the sheath (71); A reverse blocking valve seat (73) is arranged inside the sheath (71), and the reverse blocking valve seat (73) abuts against the lower joint (72); The valve flap (74) is mounted on the reverse blocking valve seat (73) via a torsion spring (75).

18. The repeatable tie-back packer according to claim 17, characterized in that: A lower connecting sleeve (8) is provided on the outer periphery of the track tube (51), and two ends of the lower connecting sleeve (8) are respectively connected to the base of the straightening block (62) and the protective sleeve (71).

19. The repeatable tie-back packer according to claim 6, characterized in that: The support cylinder (31) has a second pressurizing hole on its wall. The limiting cylinder (33) is configured to move in a direction away from the joint (21) under pressurization. A second return spring (34) is provided between the limiting cylinder (33) and the cylinder body (32).

20. A method for operating a repeatable reconnectable packer, characterized in that: The following steps are involved: The repeatable release tie-back packer is lowered into the well. During the lowering of the pipe string, the release tie-back mechanism (3) pushes the sealing locking mechanism (2) downward, so that the sealing locking mechanism (2) moves to the sealing locking position, thereby isolating the cavity of the central pipe (11) from the annulus between the packer and the casing; Continue to lower the pipe string. When the pipe string is lowered to the preset position, the center pipe is supported on the inner wall of the sleeve. The support member is moved to release the restriction on the tie-back locking claw (331), and the tie-back mechanism (3) is moved upward until the tie-back locking claw (331) is separated from the sealing locking mechanism (2), and the upper body pipe string is installed. The tie-back mechanism (3) is separated from the sealing locking mechanism (2), and the tie-back packer can be repeatedly dropped and connected to perform corresponding operations; After the operation is completed, the hand-dropping and reconnecting mechanism (3) is lowered to connect the reconnecting locking claw (331) with the sealing locking mechanism (2), and the supporting member is moved so that the supporting member is supported on the inner side of the reconnecting locking claw (331); The pipe column is lifted, and the release tie-back mechanism (3) drives the sealing locking mechanism (2) to move to the unsealing position. The cavity of the central pipe (11) is connected with the first hole (121) and the second hole (122), and the upper and lower pressures are balanced. The pipe column is continuously lifted, and the central pipe (11) is separated from the sleeve. Then, the repeatable release tie-back packer is moved to the next working position by moving the pipe column.

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