Repeatable releasing tie-back packer and operation method thereof

Abstract

The invention relates to the field of oil field downhole tools, and discloses a repeatable releasing tie-back packer and an operation method thereof. The repeatable releasing tie-back packer comprises a center mechanism, a sealing locking mechanism, a releasing tie-back mechanism and an anchoring structure, the center mechanism comprises a center pipe, an upper connecting sleeve is arranged at one end of the center pipe, and a first hole and a second hole are formed in the side wall of the upper connecting sleeve; the sealing locking mechanism comprises a connector, a limiting assembly and a mandrel. The releasing tie-back mechanism comprises a supporting cylinder, a cylinder body and a limiting cylinder. The anchoring structure includes an anchoring member and a setting locking member. When the packer is used, the releasing tie-back mechanism is separated from the sealing locking mechanism, normal use of the packer is prevented from being affected, when the position of the packer needs to be adjusted, the releasing tie-back mechanism can be connected with the sealing locking mechanism, and then the packer can be driven by the releasing tie-back mechanism to move to the next working position, so that the packer is prevented from being damaged. The problem of frequent drilling is avoided, and the construction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of downhole tools in oil fields, and in particular to a repeatable drop-out tie-back packer and an operating method thereof. Background Art

[0002] At present, the double-seal single-cage tool is widely used in layered fracturing and production operations as a mature tool technology. In the double-seal single-cage fracturing process, the distance between the upper and lower packers in the same pipe string fracturing construction is fixed and cannot be adjusted. For perforation sections with different interlayer spacing, it is necessary to frequently pull out the drill to adjust the distance between the two packers, which reduces the construction efficiency. At the same time, due to the serious erosion of the pipe string between the two packers by the large-volume sand-carrying fluid during the fracturing process, complex downhole problems such as interlayer oil pipe fracture and perforation failure often occur. Summary of the invention

[0003] In order to solve the problem that the distance between the upper and lower packers in the above-mentioned traditional tubing fracturing construction is fixed and cannot be adjusted, resulting in frequent drilling and affecting the construction efficiency, the present invention provides a repeatable drop-back packer and an operating method thereof.

[0004] The present invention provides a repeatable drop-and-tie packer, comprising:

[0005] The central mechanism comprises a central tube, one end of which is provided with an upper connecting sleeve, and a side wall of the upper connecting sleeve is provided with a first hole and a second hole communicating with the cavity of the central tube;

[0006] A sealing locking mechanism, comprising a joint, a limiting assembly and a mandrel connected to the joint, wherein a portion of the mandrel extends into the interior of the upper connecting sleeve, the joint can drive the mandrel to move between an unsealing position and a sealing locking position, so that the mandrel connects or separates the first hole and the second hole from the cavity of the central tube, and the limiting assembly is configured to limit or release the limit of the mandrel in the sealing locking position;

[0007] A hand-off reconnection mechanism, comprising a support cylinder, a cylinder sleeved on the outer periphery of the support cylinder, and a limiting cylinder arranged between the cylinder and the support cylinder, the end of the limiting cylinder is provided with a reconnection locking claw with a locking hook, the end of the support cylinder is provided with a control valve seat, the limiting cylinder 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 or separated from the control valve seat, the interior of the joint is provided with a first limiting groove matching the locking hook, and the length of the first limiting groove is greater than the length of the locking hook of the reconnection locking claw; and

[0008] The anchoring structure is arranged on the outer periphery of the central tube, 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 to be separated from the sleeve. 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.

[0009] Optionally, the limiting component includes:

[0010] A second limiting groove disposed on the outer periphery of the mandrel; and

[0011] The mandrel locking claw is arranged on the inner wall of the upper connecting sleeve and is configured as follows:

[0012] When the core shaft is in the sealing and locking position, the core shaft locking claw is engaged with the second limiting groove.

[0013] Optionally, an opening connected to the cavity of the central tube is provided in the middle of the core shaft, a check valve is provided in the opening, a bypass hole connected to the opening is provided on the side wall of the upper connecting sleeve, and the configuration is as follows:

[0014] When the core shaft is not moved to the sealing locking position, the bypass hole is opposite to the second hole, and the first hole is connected to the cavity of the central tube;

[0015] When the core shaft moves to the sealing and locking position, the bypass hole and the second hole are 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.

[0016] Optionally, a sealing packing is provided at the outer periphery of the end of the core shaft, and a core shaft valve seat is provided at the end of the center tube. When the core shaft moves to the sealing locking position, the sealing packing fits with the inner wall of the core shaft valve seat to form a seal.

[0017] Optionally, the anchoring member includes a first anchoring member body, which includes a seat body arranged on the outer periphery of the central tube, the seat body is provided with a plurality of mounting holes, 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 the seat body is provided with a cover plate for pressing the positioning anchor claw.

[0018] 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.

[0019] Optionally, the anchoring member also includes a third anchoring member body, which includes an upper cone, a lower cone and a cava arranged on the outer periphery of the central tube, the upper cone is connected to the lower rubber cylinder seat, and a protective cover is provided on the outer periphery of the upper cone and the lower cone, an opening is provided at a position of the protective cover corresponding to the cava, and a first return spring is provided between the protective cover and the cava.

[0020] Optionally, the seating and locking member comprises:

[0021] A rubber cylinder locking claw is connected to the bushing, and the rubber cylinder locking claw is slidably matched with the inner wall of the upper cone;

[0022] The annular locking block is arranged on the inner wall of the upper cone and is configured as follows:

[0023] 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.

[0024] 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.

[0025] Optionally, the seating and locking component also 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.

[0026] Optionally, the repeatable drop-and-tie packer further comprises a track switching mechanism, and the track switching mechanism comprises:

[0027] A track tube connected to an end of the center tube away from the upper connecting sleeve, the track tube is provided with a plurality of setting grooves and unsealing grooves, the plurality of setting grooves and unsealing grooves form a J-shaped track, the upper cone, the lower cone and the slips are arranged on the outer periphery of the track tube;

[0028] 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:

[0029] When the track tube is lifted, the switch ring can rotate so that the switch pin can switch between the setting groove and the unsealing groove.

[0030] Optionally, the repeatable drop-and-tie packer further comprises a straightening mechanism, wherein the straightening mechanism is sleeved on the outer circumference of the trajectory tube and frictionally matched with the inner wall of the sleeve.

[0031] Optionally, the righting mechanism comprises:

[0032] A righting base, sleeved on the outer circumference of the track tube, the righting base being connected to the lower cone;

[0033] 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 arranged between the straightening blocks and the straightening base.

[0034] Optionally, the repeatable drop tie-back packer further comprises a reverse plugging valve mechanism, and the reverse plugging valve mechanism comprises:

[0035] A sheath connected to the end of the track tube;

[0036] A lower connector connected to the sheath;

[0037] A reverse blocking valve seat is arranged inside the sheath, and the reverse blocking valve seat abuts against the lower joint;

[0038] The valve disc is mounted on the valve seat of the reverse blocking valve through a torsion spring.

[0039] 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.

[0040] Optionally, a second pressurizing hole is provided on the cylinder 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.

[0041] The present invention also provides an operating method for a repeatable drop-and-tie packer, comprising the following steps:

[0042] The repeatable drop-and-tie packer is lowered into the well. During the lowering of the tubing, the drop-and-tie mechanism pushes the sealing locking mechanism downward, so that the mandrel moves to the sealing locking position, separating the cavity of the central pipe from the annulus between the packer and the casing, and the position of the mandrel is maintained by the limit assembly;

[0043] Continue to lower the pipe string. When the pipe string is lowered to the preset position, the anchoring member works so that the anchoring member is supported on the inner wall of the sleeve and the anchoring member is kept in the state by locking the anchoring member.

[0044] The limit cylinder moves upward, so that the lock hook on the release and tie-back mechanism is separated from the control valve seat, and the tie-back lock claw is unlocked. The limit cylinder continues to move upward until the lock hook is separated from the first limit groove, the upper body string, the release and tie-back mechanism are separated from the joint, and the release and tie-back packer can be repeatedly released to perform corresponding operations;

[0045] After the operation is completed, the hand-dropping tie-back mechanism is lowered, so that the tie-back locking claw is extended into the joint, and the pipe string is pressed down. The tie-back locking claw contacts the inner wall of the joint and then contracts, so that the lock hook is separated from the control valve seat, and the pipe string is continuously pressed down, and the lock hook is stuck in the first limit groove;

[0046] The tubing is lifted, the limit assembly opens, the cavity of the central tube is connected with the first hole and the second hole, the upper and lower pressures are balanced, the tubing is continued to be lifted, the seating locking component opens, the anchoring component is reset, and the repeatable drop-out tie-back packer is moved to the next working position by moving the tubing.

[0047] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0048] When the packer provided by the present invention is in use, the release and tie-back mechanism is separated from the sealing locking mechanism to avoid affecting the normal use of the packer. When it is necessary to adjust its own position, the release and tie-back mechanism can be connected to the sealing locking mechanism, so that the packer can be moved to the next working position under the drive of the release and tie-back mechanism, avoiding the problem of frequent drilling and improving construction efficiency. At the same time, the disassembly of the release and tie-back mechanism and the joint of the present application requires actively applying a force toward the limit cylinder to prevent the release and tie-back mechanism from accidentally disengaging from the sealing locking mechanism, thereby ensuring the safety of construction. In addition, when the packer is in use, the position of the core shaft can be maintained by the limit assembly to avoid the failure of the separation function of the core shaft, and the state of the anchoring structure can be maintained by the locking member to avoid resetting of the anchoring structure, thereby ensuring the supporting effect of the anchoring member and further ensuring safe construction. In addition, the double-seal single-card fracturing method consisting of the upper and lower packers is characterized by no tubing connection between the upper and lower packers, 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. 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

[0049] 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.

[0050] In order to more clearly illustrate the implementation mode of the present invention or the technical solution in the prior art, the drawings required for use in the implementation mode or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 It is a schematic structural diagram of a repeatable drop-and-tie packer according to an embodiment of the present invention;

[0052] Figure 2 It is a schematic structural diagram of a part of the repeatable release tie-back packer in a setting state according to an embodiment of the present invention;

[0053] Figure 3 It is a structural schematic diagram of the repeatable release tie-back packer after release according to an embodiment of the present invention;

[0054] Figure 4 It is a structural schematic diagram of the repeatable drop-and-tie packer in the first half of an embodiment of the present invention;

[0055] Figure 5 It is a schematic structural diagram of the repeatable tie-back packer in the lower half of the embodiment of the present invention;

[0056] Figure 6 This is a structural schematic diagram of the drop-and-reconnect mechanism described in an embodiment of the present invention;

[0057] Figure 7 It is a structural schematic diagram of the sealing locking mechanism according to an embodiment of the present invention;

[0058] Figure 8 This is a schematic structural diagram of the first anchoring member body according to an embodiment of the present invention;

[0059] Fig. 9 This is a schematic structural diagram of the second anchoring member body according to an embodiment of the present invention;

[0060] Fig.10 is a schematic structural diagram of the third anchoring member body according to an embodiment of the present invention;

[0061] Fig.11 It is a structural schematic diagram of the righting mechanism according to an embodiment of the present invention;

[0062] Fig.12 It is a structural schematic diagram of the track switching mechanism according to an embodiment of the present invention;

[0063] Fig.13 It is a J-shaped track expansion diagram of the track switching mechanism described in the embodiment of the present invention;

[0064] Fig.14 It is a structural schematic diagram of the reverse blocking valve mechanism described in an embodiment of the present invention.

[0065] Description of Reference Numerals

[0066] 1. Center mechanism; 11. Center tube; 111. Mandrel valve seat; 12. Upper connecting sleeve; 121. First hole; 122. Second hole; 2. Sealing locking mechanism; 21. Connector; 211. First limit groove; 212. Guide groove; 22. Limit assembly; 221. Second limit groove; 222. Mandrel locking claw; 23. Mandrel; 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 body; 33, limit cylinder; 331, reconnection 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 reset spring; 4114, cover plate; 412, second anchor member body; 4121, bushing; 4122, upper rubber cylinder seat; 4123, lower rubber cylinder seat; 4124, rubber cylinder; 413, third anchor member body; 4131, upper cone; 4132, lower cone; 4133, slip; 4134, protective cover; 4135, first reset spring; 42, seat lock fixing member; 421, rubber cylinder lock claw; 422, annular lock block; 4 23. 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 blocking valve mechanism; 71. Sleeve; 72. Lower joint; 73. Reverse blocking valve seat; 74. Valve disc; 75. Torsion spring; 8. Lower connecting sleeve. DETAILED DESCRIPTION

[0067] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0068] 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; obviously, the implementation methods in the specification are only part of the implementation methods of the present invention, rather than all of the implementation methods.

[0069] Combination Figures 1 to 5 As shown, the repeatable release tie-back packer provided in the embodiment of the present invention comprises a central mechanism 1 , a sealing locking mechanism 2 , a release tie-back mechanism 3 and an anchoring structure 4 .

[0070] The central mechanism 1 includes a central tube 11, one end of which is provided with an upper connecting sleeve 12, and the side wall of the upper connecting sleeve 12 is provided with a first hole 121 and a second hole 122 connected to the cavity of the central tube 11. Specifically, the central tube 11 has a first end and a second end corresponding to each other. Figure 2 Taking the direction shown 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 indirectly connected by other mechanisms.

[0071] Combination Figure 4 and Figure 7 As shown, the sealing locking mechanism 2 includes a joint 21, a limiting assembly 22, and a mandrel 23 connected to the joint 21. Part of the mandrel 23 extends into the interior of the upper connecting sleeve 12. The joint 21 can drive the mandrel 23 to move between the unsealing position and the sealing locking position, so that the mandrel 23 connects or separates the first hole 121 and the second hole 122 from the cavity of the central tube 11. The limiting assembly 22 is configured to be able to restrict or release the mandrel 23 in the sealing locking position. Among them, one end of the mandrel 23 extends into the interior of the joint 21 and is threadedly connected to the joint 21 to increase the convenience of disassembly and assembly. At the same time, it can be further tightened by a stop screw to increase the firmness of the connection. The other end of the mandrel 23 extends into the interior of the upper connecting sleeve 12, and the extending end of the mandrel 23 is provided with a step surface. The upper connecting sleeve 12 is sleeved on the step surface of the mandrel 23 to prevent the mandrel 23 from detaching from the upper connecting sleeve 12.

[0072] Combination Figure 4 and Figure 6 As shown, the hand-off reconnection mechanism 3 includes 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. Among them, the end of the support cylinder 31 extends out of the cylinder body 32, and a limiting ring is arranged on the outer periphery of the support cylinder 31, so as to limit the moving range of the limiting cylinder 33 through the limiting ring to prevent the limiting cylinder 33 from extending out of the cylinder body 32. The end of the limiting cylinder 33 is provided with a reconnection locking claw 331 with a locking hook, and the locking hook is arranged on the outer side of the end of the reconnection locking claw 331. The end of the support cylinder 31 is threadedly connected with a control valve seat 311, 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 separated from the control valve seat 311. The inside 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 reconnection locking claw 331.

[0073] Under normal conditions, the lock hook of the reconnection lock claw 331 is supported on the outer side of the control valve seat 311 to prevent the reconnection lock claw 331 from being folded inward.

[0074] 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 return locking claw 331 is inserted into the connector 21. The return 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 return locking claw 331 is then expanded and the limiting cylinder 33 is reset so that the locking hook is supported on the outer periphery of the control valve seat 311 to avoid accidental unlocking of the return locking claw 331, thereby ensuring safety in use.

[0075] When the hand-dropping reconnection mechanism 3 needs to be separated from the connector 21, since the length of the first limiting groove 211 is greater than the length of the lock hook of the reconnection locking claw 331, the lock hook can move in the first limiting groove 211. The limiting cylinder 33 moves in a direction away from the control valve seat 311, so that the lock hook is separated from the control valve seat 311 (the lock hook is always in the first limiting groove 211), and then the hand-dropping reconnection mechanism 3 is lifted up, so that the lock hook can be separated from the first limiting groove 211, completing the separation process of the hand-dropping reconnection mechanism 3, and the operation is convenient.

[0076] The anchoring structure 4 is arranged on the outer periphery of the central pipe 11, and includes an anchoring member 41 and a seated locking member 42. The anchoring member 41 is configured to be supported on the inner wall of the sleeve, or separated from the sleeve, and the seated 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 seated state, the anchoring member 41 can be deployed by lowering the pipe string to support the inner wall of the sleeve. At this time, the state of the anchoring member 41 can be maintained by the seated locking member 42 to ensure the support effect of the anchoring member 41.

[0077] The first hole 121 and the second hole 122 are two holes formed on the side wall of the connecting sleeve 12. When the sealing locking mechanism 2 is in a locked state, Figure 2 As shown, the first hole 121 corresponds to the bypass hole 235 on the core shaft 23, connecting the inside and the outside of the packer; when the sealing locking mechanism 2 is not locked, that is, the core shaft 23 is completely disengaged from the core shaft valve seat 111 described below, as shown in FIG. Figure 7 As shown, 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 of which are channels for reverse circulation of the packer. The two holes can ensure that no matter what working conditions the mandrel 23 of the packer is in, one of the holes can be guaranteed to completely correspond to the bypass hole 235 on the mandrel 23, retaining the largest reverse circulation channel and minimizing the erosion of the mandrel 23 of the packer by the liquid.

[0078] When the packer provided by the present invention is in use, the release and tie-back mechanism 3 is separated from the sealing locking mechanism 2 to avoid affecting the normal use of the packer. When it is necessary to adjust its own position, the release and tie-back mechanism 3 can be connected to the sealing locking mechanism 2, so that the packer can be moved to the next working position under the drive of the release and tie-back mechanism 3, avoiding the problem of frequent drilling and improving construction efficiency. At the same time, the disassembly of the release and tie-back mechanism 3 and the joint 21 of the present application requires actively applying a force toward the limit cylinder 33 to prevent the release and tie-back mechanism 3 from accidentally disengaging from the sealing locking mechanism 2, thereby ensuring the safety of construction. In addition, when the packer is in use, the position of the core shaft 23 can be maintained by the limit assembly 22 to avoid the failure of the isolation function of the core shaft 23, and the state of the anchoring structure 4 can be maintained by the locking member 42 to avoid the anchoring structure 4 from being reset, thereby ensuring the supporting effect of the anchoring member 41 and further ensuring the safe construction. In addition, the double-seal single-card fracturing method consisting of the upper and lower packers is characterized by no tubing connection between the upper and lower packers, 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. Therefore, it can avoid tubing erosion between the packers, and thus avoid complex downhole problems such as interlayer oil pipe breakage and perforation failure.

[0079] In some embodiments, Figure 7 As shown, the limiting assembly 22 includes a second limiting groove 221 arranged on the outer periphery of the portion of the spindle 23 extending into the upper connecting sleeve 12 and a spindle locking claw 222 arranged on the inner wall of the upper connecting sleeve 12, and the second limiting groove 221 matches the spindle locking claw 222. When the spindle 23 is in the sealing locking position, the spindle locking claw 222 is engaged with the second limiting groove 221, and when the hand-release reconnection mechanism 3 is lifted, the hand-release reconnection mechanism 3 can drive the spindle 23 to move upward through the joint 21, thereby separating the spindle locking claw 222 from the spindle 23, and completing the unlocking of the spindle 23. The limiting assembly 22 of this design is simple in structure, and the separation or engagement process can be completed by only lifting or lowering the hand-release reconnection mechanism 3, and the operation is convenient.

[0080] The middle part of the mandrel 23 is provided with an opening 231 connected to the cavity of the central tube 11, and a check 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 upper connecting sleeve 12. When the mandrel 23 does not move to the sealing and 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 mandrel 23 moves to the sealing and locking position, the bypass hole 235 is opposite to the position of the second hole 122, and the mandrel 23 blocks the end of the central tube 11 to separate the first hole 121 from the cavity of the central tube 11. The mandrel 23 under this design mode occupies less space, making the overall structure more compact. Moreover, whether in a sealed state or an unsealed state, it can ensure that the position of the first hole 121 or the second hole 122 is completely corresponding to the bypass hole 235, so as to maximize the flow rate of the fluid and meet the design requirements.

[0081] Further optimized, a sealing packing 233 is provided at the outer periphery of the end of the mandrel 23, and a mandrel valve seat 111 is provided at the end of the center tube 11. When the mandrel 23 moves to the sealing locking position, the sealing packing 233 fits the inner wall of the mandrel valve seat 111 to form a seal, thereby ensuring the tightness of the connection and the isolation effect. Among them, the end of the mandrel 23 is threadedly connected with a packing lock cap, 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, and the sealing packing 233 can be pressed by screwing the packing lock cap to ensure the fixing effect of the sealing packing 233. A conical hole is provided inside the packing lock cap, and the check valve 232 is installed at the position of the conical hole to support the check valve 232 through the slope of the conical hole. Among them, the function of the check valve 232 is that after the sealing locking mechanism 2 is sealed and locked, it can prevent the upper liquid from entering the lower part of the packer through the check valve 232.

[0082] For further optimization, a valve plate 234 may be provided inside the opening 231 of the mandrel 23, and the valve plate 234 is supported on the inner wall of the mandrel 23 through the end of the packing lock cap to prevent the valve plate 234 from moving along the axial direction of the mandrel 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] In some embodiments, Figure 8As shown, the anchoring member 41 includes a first anchoring member body 411, which includes a seat body 4111 arranged on the outer periphery of the central pipe 11, a plurality of mounting holes are arranged on the seat body 4111, and a positioning anchor claw 4112 is arranged inside the mounting hole, and the positioning anchor claw 4112 is connected to the bottom wall of the mounting hole through an anchor claw reset spring 4113, and a first pressurizing hole is arranged at a position corresponding to the mounting hole of the seat body 4111, and a cover plate 4114 for pressing the positioning anchor claw 4112 is arranged on the seat body 4111. In the setting state, the first pressurizing hole can be used to pressurize the inside of the mounting hole. At this time, 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 the positioning anchor claw 4112 extends outward under the action of the internal and external pressure difference, and the positioning anchor claw 4112 is anchored on the inner wall of the casing. In the unsealing state, the positioning anchor claw 4112 can be reset under the action of the anchor claw reset spring 4113. Among them, the mounting holes can be blind holes, and the number of blind holes is 6, the 6 blind holes are divided into two rows and are symmetrically distributed along the circumferential direction of the central tube 11, and grooves are designed on the outer arc surfaces of the positioning anchor claw 4112 and the seat body 4111, and a cover plate 4114 is installed on the groove to compress the positioning anchor claw 4112 and the anchor claw reset spring 4113, and the cover plate 4114 is fixed by tightening screws.

[0084] Specifically, the end of the seat body 4111 extends out of the first end of the center tube 11, and the core shaft valve seat 111 is threadedly connected to the inner wall of the extended end of the seat body 4111, which increases the convenience of disassembly and assembly. An O-ring of the core shaft valve seat 111 is provided between the core shaft 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 part of the core shaft locking claw 222 extends between the seat body 4111 and the upper connecting sleeve 12. The upper connecting sleeve 12, part of the core shaft 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.

[0085] In other embodiments, Fig. 9As shown, 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 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 periphery of the bushing 4121. The bushing 4121 is clearance-matched with the central pipe 11 to form a hydraulic channel connected to the first pressurized hole, and 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, and the outer environment of the positioning anchor claw 4112 is the oil casing annulus on the upper part of 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 column, wherein the positioning anchor claw 4112 is a conventional technology in the field, and therefore, its working principle is not described in detail.

[0086] It is worth noting that the third anchoring member body 413 described below is activated when the packer is set. After the third anchoring member body 413 is activated, it can ensure that the pipe string does not move up and down. After the third anchoring member body 413 is activated, if the lower pressure of the packer is higher than the upper pressure, the first anchoring member body 411 is activated to further ensure that the pipe string does not move up and down. If the lower pressure of the packer is not higher than the upper pressure, at this time, the first anchoring member body 411 will not be activated, and there will be no other impact on the pipe string.

[0087] The upper rubber cylinder seat 4122 and the bushing 4121 are connected to the seat body 4111 respectively, and 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 locking and the first anchoring member body 411. At this time, since the rubber cylinder 4124 can be compressed, the bushing 4121 moves relatively with the upper rubber cylinder seat 4122, the lower rubber cylinder seat 4123 and the rubber cylinder 4124. In this process, the rubber cylinder 4124 is compressed and expanded to support on the inner wall of the sleeve to play a positioning role.

[0088] Specifically, a partition plate is provided at one end of the seat body 4111 facing the upper glue cylinder seat 4122, the bushing 4121 is arranged on the inner side of the partition plate, the upper glue cylinder seat 4122 is wrapped on the outer side of the partition plate, and the upper glue cylinder seat 4122 is threadedly connected with the partition plate to increase the convenience of disassembly and assembly. In addition, the inner ring of the upper glue 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, and an annular baffle is provided at the end of the bushing 4121, which can slide in the gap and limit the movement range of the annular baffle through the inner ring of the upper glue cylinder seat 4122 to avoid excessive stroke.

[0089] In other embodiments, Fig.10 As shown, the anchoring member 41 further includes a third anchoring member body 413, which includes an upper cone 4131, a lower cone 4132, and a slip 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 the third anchoring member body 413 can be disposed on the periphery of the central pipe 11 through 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 sleeve is provided on the outer periphery of the upper cone 4131 and the lower cone 4132. The protective sleeve is sleeved on the outer cross section of the upper cone 4131 so that the protective sleeve can drive the upper cone 4131 to move downward. The protective sleeve is threadedly connected to the lower cone 4132. An opening is provided at a position corresponding to the protective sleeve and the cava 4133. A first return spring 4135 is provided between the protective sleeve and the cava 4133.

[0090] Specifically, the slopes of the upper cone 4131 and the lower cone 4132 are arranged oppositely, and there are multiple slips 4133, which are installed on the outer peripheral surface of the support mechanism (the track tube 51 described below). Slopes are also arranged at the positions corresponding to the upper cone 4131 and the lower cone 4132, so that the contact surface between the slip 4133 and the upper cone 4131 and the lower cone 4132 is a slope. A first return spring 4135 is arranged between the middle part of the slip 4133 and the protective sleeve, and the first return spring 4135 is always in a compressed state to prevent the slip 4133 from starting prematurely during the lowering of the packer. During the lowering of the pipe string, the upper cone 4131 can be pushed to move by the lower rubber cylinder seat 4123, and the slip 4133 moves outward under the action of the slope to extend out of the opening, and the slip 4133 is supported on the inner wall of the sleeve to play 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.

[0091] Further optimization, such as Fig. 9 As shown, the third anchoring member body 413 also includes a locking spring 423, which is arranged between the protective sleeve 4134 and the lower rubber cylinder seat 4123, and the locking spring 423 is sleeved on the outer periphery of the upper cone 4131. When the third anchoring member body 413 is anchored, the lower cone 4132 moves upward to drive the protective sleeve 4134 to squeeze the locking spring 423, so when the third anchoring member body 413 is anchored, the locking spring 423 is always in a compressed state. When the packer is lifted, the pipe string drives the upper cone 4131 upward, and at the same time, the locking spring 423 pushes the protective sleeve 4134 downward, and the protective sleeve 4134 drives the lower cone 4132 downward, so that the upper cone 4131 moves upward, the lower cone 4132 moves downward, and the anchor claw 4133 returns to its original state under the action of the first reset spring 4135, and the anchor state is released.

[0092] 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, so that the repeatable release tieback packer is evenly stressed to ensure the setting effect of the repeatable release tieback packer and ensure that the packer is subjected to downward and upward pressure during use. That is, after the packer is set, the rubber cylinder 4124 seals the annulus between the pipe string and the casing, and the core shaft 23 inside the packer seals the internal annulus of the pipe string, so a barrier can be formed after the packer is set to prevent the upper and lower parts of the packer from being connected.

[0093] In some embodiments, Fig. 9 As shown, the seat locking member 42 includes a rubber cylinder locking claw 421 and an annular locking block 422. The rubber cylinder locking claw 421 is 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. When the rubber cylinder 4124 is in a compressed state, the rubber cylinder locking claw 421 is engaged with the annular locking block 422, and the rubber cylinder 4124 can be kept in a compressed state through the rubber cylinder locking claw 421 and the annular locking block 422.

[0094] Specifically, the end of the rubber cylinder locking claw 421 is connected to the outer circumference of the end of the bushing 4121 by a thread to increase the convenience of disassembly and assembly. The inner wall of the lower rubber cylinder seat 4123 is processed with double steps to accommodate the end of the rubber cylinder locking claw 421 and the end of the upper cone 4131 respectively, so that the structure is more compact. The locking hook of the rubber cylinder locking claw 421 faces outward and can slide relative to the inner wall of the upper cone 4131. The end of the locking hook of the rubber cylinder locking claw 421 is provided with a slope surface. When the rubber cylinder locking claw 421 moves relative to the inner wall of the upper cone 4131, the locking hook of the rubber cylinder locking claw 421 contacts the inner wall of the annular locking block 422, and the rubber cylinder locking claw 421 is retracted inwardly under the action of the slope surface, so that it can move to the other side of the annular locking block 422, so as to realize the clamping of the rubber cylinder 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.

[0095] Further optimized, the seating locking component 42 also includes a slip ring 424, which is arranged on the outer periphery of the center tube 11, and the inner side of the slip ring 424 is provided with a second slope surface matching 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 inward to disengage from the annular locking block 422.

[0096] Specifically, when unsealing is required, the pipe column is lifted up. 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 unlocked, 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.

[0097] The annular space between the outside of the pipe column and the inside of the casing of the present invention is sealed by the rubber tube 4124, and the inside of the packer is sealed by the core shaft 23, with reliable sealing performance. The inner and outer seals are locked by the limit assembly 22 and the locking member 42 respectively, which can ensure that the inner and outer seals of the packer will not be unlocked and failed in the middle of the sealing process due to unexpected circumstances. That is, after the inner and outer seals are formed, the role of the packer here is equivalent to a bridge plug after the hand is set, which isolates the lower well section, and the upper well section isolated by the packer can be constructed.

[0098] Combination Fig.12 and Fig.13As shown, the repeatable drop-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 center tube 11 away from the upper connecting sleeve 12 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 groove 511 is greater than the length of the unsealing groove 512, and 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 has two symmetrically distributed through holes processed 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.

[0099] like Fig.11 As shown, the repeatable release tie-back packer of the present application further includes a straightening mechanism 6, which is sleeved on the outer periphery of the track tube 51, and the straightening mechanism 6 is frictionally matched with the inner wall of the sleeve. The straightening mechanism 6 is used to ensure that the packer is in a straightened state in the wellbore, and at the same time, it can provide a certain friction force for the packer to prevent the packer from being lowered too fast.

[0100] 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 the straightening base 61 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, so that the straightening block 62 is pushed out of the straightening base 61 by the compression spring 63. The straightening block 62 is always in an extended state with 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 provided on the straightening block 62, and part of the compression spring 63 is in the blind hole, so that the compression spring 63 is limited by the blind hole, and the compression direction of the compression spring 63 can be limited. The elastic force of the compression spring 63 can be designed according to actual needs.

[0101] Further optimized, 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, and correspondingly, bosses are respectively provided at both ends of the straightening block 62, and the two bosses are respectively in contact with the end of the straightening pressure ring 64 and the pressure plate 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.

[0102] like Fig.14 As shown, the repeatable drop-back packer of the present application also includes a reverse plugging valve mechanism 7, which includes a sheath 71, a lower joint 72, a reverse plugging valve seat 73 and a valve flap 74. The sheath 71 is connected to the end of the track tube 51. The lower joint 72 is connected to the sheath 71. The reverse plugging valve seat 73 is arranged inside the sheath 71, and the reverse plugging valve seat 73 abuts against the lower joint 72. The valve flap 74 is installed on the reverse plugging valve seat 73 through a torsion spring 75.

[0103] Specifically, the inner wall of the sleeve 71 is processed with a step surface, the reverse blocking valve seat 73 is installed in the sleeve 71, and the upper end of the reverse blocking valve seat 73 contacts the step surface of the inner wall of the sleeve 71. A reverse blocking valve O-ring is installed between the reverse blocking valve seat 73 and the sleeve 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 sleeve 71. The reverse blocking valve seat 73 is installed with a valve flap 74, and the reverse blocking valve seat 73 and the valve flap 74 are connected by a torsion spring 75.

[0104] 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 liquid force at the bottom of the packer, and the force is transmitted to the sleeve 71 connected thereto by the reverse blocking valve mechanism 7, and then continues to transmit the force to the lower cone 4132, further squeezing the cava 4133 to assist the third anchoring member body 413.

[0105] Further optimized, the outer periphery of the track tube 51 is provided with a lower connecting sleeve 8, and the two ends of the lower connecting sleeve 8 are respectively connected to the base of the straightening block 62 and the sleeve 71 to increase the firmness of the connection and the compactness of the structure. Specifically, one end of the lower connecting sleeve 8 is threadedly connected to the pressure ring of the straightening block 62, and the other end of the lower connecting sleeve 8 is threadedly connected to the sleeve 71. The lower connecting sleeve 8 presses the end face of the switching ring 52 to ensure that the switching ring 52 moves along the J-shaped track.

[0106] In some embodiments, a second pressurized hole is provided in 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 state, and a second return spring 34 is provided between the limiting cylinder 33 and the cylinder body 32 .

[0107] Specifically, an annular push plate is provided at the end of the limit tube 33 extending between the support tube 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 tube 31, and a second sealing ring 39 is provided on the side of the second pressurizing hole away from the first sealing ring 38, so that an injection space connected to the second pressurizing hole is formed between the first sealing ring 38 and the second sealing ring 39. When pressure is injected into the injection space, the pressure will push the annular push plate to move in a direction away from the joint 21, so that the reconnection locking claw 331 is separated from the control valve seat 311. When the hand-off reconnection mechanism 3 is separated from the joint 21, the injection pressure is stopped, and the reconnection locking claw 331 is reset under the action of the second reset spring 34. The reconnection locking claw 331 of this design is separated from the control valve seat 311 by pressurization, avoiding misoperation and effectively ensuring the safety of construction.

[0108] Specifically, the hand-off reconnection mechanism 3 of the present application also includes an upper joint 35 connected to the pipe column, the cylinder 32 is threadedly connected to the outer wall of the upper joint 35, the support cylinder 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 cylinder 32 and the support cylinder 31, the second return spring 34 and part of the reconnection claw 331 are in the annular space, and the second return spring 34 is connected to the spring seat 36. The end of the cylinder 32 is threadedly connected with a guide shoe 37, and the guide shoe 37 is used to control the extension length of the reconnection claw 331. The outer periphery of the control valve seat 311 is provided with a sealing rubber sleeve 3111 to increase the tightness of the connection between the control valve seat 311 and the joint 21.

[0109] It is understandable that, in the present application, sealing rings may be reasonably provided between components that require sealing, so as to ensure a sealed connection between the corresponding components.

[0110] The end of the connector 21 of the present application is provided with a guide groove 212, which is open, and the guide groove 212 is connected to the first limiting groove 211 through a transition groove. When the reconnection locking claw 331 is inserted into the connector 21, the reconnection locking claw 331 is preferentially closed under the action of the guide groove 212, so that the lock hook of the reconnection locking claw 331 can be inserted into the first limiting groove 211, increasing the convenience of inserting the reconnection locking claw 331. In addition, the side walls at both ends of the first limiting groove 211 are provided with slopes to facilitate the lock hook to detach from the first limiting groove 211.

[0111] The present invention also provides an operating method of the above-mentioned repeatable drop-and-tie packer, comprising the following steps:

[0112] Step S1, lowering the repeatable release and tie-back packer into the well. During the lowering of the tubing, the release and tie-back mechanism 3 pushes the sealing locking mechanism 2 downward, so that the core shaft 23 moves to the sealing locking position, separating the cavity of the central pipe 11 from the annulus between the packer and the casing, and maintaining the position of the core shaft 23 by the limit assembly 22.

[0113] Specifically, during the running of the tubing string, due to the friction between the straightening mechanism 6 and the inner wall of the sleeve, the joint 21 of the packer pushes the mandrel 23 downward, and the mandrel 23 contacts the mandrel valve seat 111 to form a seal, so as to separate the cavity of the central pipe 11 from the annulus between the packer and the casing. The mandrel locking claw 222 is locked with the second limiting groove 221 on the mandrel 23, and the function of the sealing locking mechanism 2 is activated.

[0114] Step S2, continue to lower the pipe string. When the pipe string is lowered to the preset position, the anchoring member 41 works so that the anchoring member 41 is supported on the inner wall of the sleeve and the state of the anchoring member 41 is maintained by locking the locking member 42.

[0115] Specifically, the pipe string is continuously lowered, and the pipe string overcomes the friction between the straightening mechanism 6 and the inner wall of the sleeve and is lowered to the designed position. The pipe 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 pipe 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 pipe 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 pipe string continues to be lowered, the rubber cylinder 4124 is compressed to form a seal with the inner wall of the sleeve, the rubber cylinder locking claw 421 is engaged with the annular locking block 422, and the locking function of the setting lock component 42 is activated, and the packer is set. Among them, the structural form of the setting lock component 42 has been described above and is not explained in detail here.

[0116] In step S3, the limiting cylinder 33 moves upward, so that the locking hook on the release and reconnection mechanism 3 is separated from the control valve seat 311, and the reconnection locking claw 331 is unlocked. The limiting cylinder 33 continues to move upward until the locking hook is separated from the first limiting groove 211, the upper body pipe string, the release and reconnection mechanism 3 is separated from the joint 21, and the release and reconnection of the packer can be repeated to perform corresponding operations.

[0117] Specifically, the liquid is pumped into the tubing column to exert pressure, and the limit cylinder 33 moves upward under the action of the liquid pressure. A steel ball of suitable size is thrown into the tubing column, and the steel ball sits on the conical surface of the control valve seat 311, and the steel ball forms a seal with the control valve seat 311. Pressure is pumped into the tubing column from the wellhead, and the pressure enters the injection pressure space through the channel in the support cylinder 31 and the second pressurized hole. The resulting pressure difference pushes the reconnection claw 331 to move up, and pushes the support cylinder 31 to move down, 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 hand-release reconnection mechanism 3 pushes the reconnection claw 331 to move up, and the lock between the reconnection claw 331 and a limit groove is completely released. Continue to lift the tubing column, and the tubing column drives the entire hand-release reconnection mechanism 3 to move up, and the hand-release reconnection mechanism 3 is separated from the joint 21, and the packer is released successfully. When the hand-release 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 resetting spring 34 .

[0118] Step S4, after the operation is completed, the hand-release reconnection mechanism 3 is lowered, so that the reconnection locking claw 331 extends into the joint 21, and the pipe string is pressed down. The reconnection locking claw 331 contacts the inner wall of the joint 21 and then contracts, so that the locking hook is separated from the control valve seat 311, and the pipe string is continuously pressed down, and the locking hook is stuck in the first limit groove 211.

[0119] Specifically, the hand-release tie-back mechanism 3 is lowered to the sealing 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 continuously pressed down, and the tie-back locking claw 331 is retracted under force and detached from the support tube 31. The support tube 31 continues to go down into the interior of the joint 21. When the support tube 31 is completely separated from the reconnection locking claw 331, the reconnection locking claw 331 shrinks inwardly under the action of the downward pressure of the tubing string, and the overall outer diameter of the locking claw 311 shrinks. The tubing string continues to descend, and the retracted reconnection locking claw 331 passes through the inner wall of the joint 21 and enters the first limiting groove 211. After the locking claw 311 enters the interior of the first limiting groove 211, under the action of 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 reconnection locking claw 331 form a forced lock again to prevent the reconnection locking claw 331 from being accidentally unlocked from the joint 21. The reconnection of the drop-down reconnection mechanism 3 and the packer is completed.

[0120] Step S5, lift the tubing string, open the limit assembly 22, connect the cavity of the central pipe 11 with the first hole 121 and the second hole 122, balance the upper and lower pressures, continue to lift the tubing string, open the seating locking member 42, reset the anchoring member 41, and move the repeatable drop-out packer to the next working position by moving the tubing string.

[0121] Specifically, the tubing string 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 string is lowered to seal the packer, and the rubber cylinder 4124 is compressed and sealed, sealing the 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 check 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 string 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, and the packer is prevented from encountering resistance when being lifted), and the anchor claw is recovered under the action of the reset spring. Continue to lift the pipe string, the slip ring 424 compresses the rubber cylinder locking claw 421 and forcibly retracts it, the locking between the rubber cylinder locking claw 421 and the upper cone 4131 is released, and the upper anchoring mechanism is released. The pipe string moves upward, the rubber cylinder 4124 is released from the compressed state, the upper cone 4131 moves upward, the slip 4133 is recovered under the action of the first return spring 4135, the lower anchoring mechanism is released, and the packer is unsealed. Continue to lift and drag the pipe string to the next designed position, repeat the above steps, and the pipe string can be moved to multiple positions.

[0122] In addition, after the packer is set and released, the effectiveness of the packer seal can be verified by pressurizing the string to ensure the sealing effect.

[0123] The present application can effectively solve the problem that the double-seal single-strap fracturing process needs to frequently pull out the drill bit to adjust the distance between the two packers, and the pipe string between the two packers is severely eroded, and realizes the double-seal single-strap fracturing process technology with free distance without interlayer connecting oil pipes, effectively improving the efficiency of on-site construction operations.

[0124] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0125] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be 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 will not be limited to the embodiments described herein, but should conform to the widest scope consistent with the principles and novel features invented herein.

Claims

1. A repeatable tie-back packer, characterized in that: include: A central mechanism (1) comprises a central tube (11), one end of the central tube (11) being provided with an upper connecting sleeve (12), a side wall of the upper connecting sleeve (12) being provided with a first hole (121) and a second hole (122) communicating with a cavity of the central tube (11); A sealing locking mechanism (2), comprising a joint (21), a limiting assembly (22) and a core shaft (23) connected to the joint (21), wherein a portion of the core shaft (23) extends into the interior of the upper connecting sleeve (12), and the joint (21) is capable of driving 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; A hand-dropping reconnection mechanism (3), comprising 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); a reconnection locking claw (331) with a locking hook is provided at the end of the limiting cylinder (33); a control valve seat (311) is provided 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 with the locking hook is provided inside the connector (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); as well as The anchoring structure (4) is arranged on the outer periphery of the central tube (11), and comprises an anchoring member (41) and a seating locking member (42), wherein 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.

2. The repeatable tie-back packer according to claim 1, 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 core shaft locking claw (222) is arranged on the inner wall of the upper connecting sleeve (12) 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).

3. The repeatable tie-back packer according to claim 1, characterized in that: The core shaft (23) is provided with an opening (231) in the middle thereof and connected to the cavity of the central tube (11); a check valve (232) is provided in the opening (231); a bypass hole (235) connected to the opening (231) is provided on the side wall of the upper connecting sleeve (12); 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).

4. The repeatable tie-back packer according to claim 3, 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 end 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.

5. The repeatable tie-back packer according to claim 1, 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).

6. The repeatable tie-back packer according to claim 5, 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).

7. The repeatable tie-back packer according to claim 6, 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).

8. The repeatable tie-back packer according to claim 7, characterized in that: The seating and locking member (42) comprises: A rubber cylinder locking claw (421) is 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).

9. The repeatable tie-back packer according to claim 7, 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).

10. The repeatable tie-back packer according to claim 8, 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).

11. The repeatable tie-back packer according to claim 7, 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 upper connecting sleeve (12); 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).

12. The repeatable tie-back packer according to claim 11, 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.

13. The repeatable tie-back packer according to claim 12, 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).

14. The repeatable tie-back packer according to claim 13, 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).

15. The repeatable tie-back packer according to claim 14, 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).

16. The repeatable tie-back packer according to claim 1, 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).

17. A method for operating a repeatable tie-back packer according to any one of claims 1 to 16, characterized in that: The following steps are involved: The reusable releasable tie-back packer is lowered into the well. During the lowering of the pipe string, the releasable tie-back mechanism (3) pushes the sealing locking mechanism (2) downward, so that the core shaft (23) moves to the sealing locking position, the cavity of the central pipe (11) is separated from the annulus between the packer and the casing, and the position of the core shaft (23) is maintained by the limit assembly (22); The pipe string is continued to be lowered. When the pipe string is lowered to a preset position, the anchoring member (41) works so that the anchoring member (41) is supported on the inner wall of the sleeve and the state of the anchoring member (41) is maintained by seating the locking member (42). The limiting cylinder (33) moves upward, so that the lock hook on the hand-release and reconnection mechanism (3) is separated from the control valve seat (311), and the reconnection lock claw (331) is unlocked. The limiting cylinder (33) continues to move upward until the lock hook is separated from the first limiting groove (211), the upper body pipe string, and the hand-release and reconnection mechanism (3) is separated from the joint (21), and the hand-release and reconnection packer can be repeatedly released to perform corresponding operations; After the operation is completed, the hand-dropping reconnection mechanism (3) is lowered, so that the reconnection locking claw (331) extends into the joint (21), and the pipe column is pressed downward. The reconnection locking claw (331) contacts the inner wall of the joint (21) and then contracts, so that the locking hook is separated from the control valve seat (311), and the pipe column is continuously pressed downward, and the locking hook is locked into the first limit groove (211); The pipe string is lifted, the limit assembly (22) is opened, the cavity of the central pipe (11) is connected with the first hole (121) and the second hole 122, the upper and lower pressures are balanced, the pipe string is continued to be lifted, the seating locking member (42) is opened, the anchoring member (41) is reset, and the repeatable releasable tie-back packer is moved to the next working position by moving the pipe string.

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