Repeatable free point backoff packer and method of operation

Abstract

This invention relates to the field of oilfield downhole tools and discloses a reusable release / reconnect packer and its operating method. The reusable release / reconnect packer includes a central mechanism, a sealing and locking mechanism, a release / reconnect mechanism, and an anchoring structure. The central mechanism includes a central tube with an upper connecting sleeve at one end. The side wall of the upper connecting sleeve has a first hole and a second hole. The sealing and locking mechanism includes a connector, a limiting component, and a mandrel. The release / reconnect mechanism includes a support cylinder, a cylinder body, and a limiting cylinder. The anchoring structure includes an anchoring component and a setting and locking component. In use, the release / reconnect mechanism and the sealing and locking mechanism of the packer are separated, avoiding interference with the normal operation of the packer. When position adjustment is required, the release / reconnect mechanism can be connected to the sealing and locking mechanism, allowing the packer to move to the next working position under the action of the release / reconnect mechanism, avoiding frequent tripping and improving construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole tools, and more specifically to a reusable packer and its operation method. Background Technology

[0002] Currently, the dual-packer single-packer fracturing tool is widely used as a mature technology in layered fracturing and production operations. In this process, the spacing between the upper and lower packers is fixed and cannot be adjusted during the same fracturing run. For perforated sections with varying layer spacing, frequent tripping is required to adjust the spacing between the two packers, resulting in low efficiency. Furthermore, the large volume of proppant-carrying fluid during fracturing severely erodes the tubing between the two packers, frequently leading to complex downhole problems such as interlayer tubing fractures and perforation failures. Summary of the Invention

[0003] To address the problem of fixed and unadjustable spacing between the upper and lower packers in traditional tubular fracturing operations, which leads to frequent drill trips and reduced construction efficiency, this invention provides a reusable packer that can be repeatedly released and reconnected, along with its operation method.

[0004] This invention provides a reusable drop-and-reconnect packer, comprising:

[0005] A central mechanism includes a central tube, one end of which is provided with an upper connecting sleeve, and the 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 and locking mechanism includes a connector, a limiting component, and a spindle connected to the connector. Part of the spindle extends into the interior of the upper connecting sleeve. The connector can move the spindle between an unsealed position and a sealed and locked position, so that the spindle communicates with or separates the first hole and the second hole from the cavity of the central tube. The limiting component is configured to restrict or release the spindle when it is in the sealed and locked position.

[0007] A release and reconnection mechanism includes a support cylinder, a cylinder body sleeved around the outer periphery of the support cylinder, and a limiting cylinder disposed between the cylinder body 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 move axially, allowing the locking hook to support itself on the outer periphery of the control valve seat or disengage from the control valve seat. The connector has a first limiting groove inside that matches 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.

[0008] An anchoring structure, disposed on the outer periphery of the central tube, includes an anchoring member and a seat 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 seat 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 is provided on the outer periphery of the mandrel; and

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

[0012] When the mandrel is in the sealed and locked position, the mandrel locking claw engages with the second limiting groove.

[0013] Optionally, the mandrel has an opening in its middle portion that communicates with the cavity of the central tube, and a check valve is installed inside the opening. The side wall of the upper connecting sleeve has a bypass hole that communicates with the opening, and is configured as follows:

[0014] When the mandrel is not moved to the sealed 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 mandrel moves to the sealed locking position, the bypass hole and the second hole are positioned opposite each other, and the mandrel blocks the end of the central tube to isolate the first hole from the cavity of the central tube.

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

[0017] Optionally, the anchoring component includes a first anchoring component body, the first anchoring component body including a seat body disposed on the outer periphery of the central tube, the seat body having a plurality of mounting holes, the interior of the mounting holes having positioning anchor claws, the positioning anchor claws being connected to the bottom wall of the mounting holes by anchor claw return springs, the seat body having a first pressure hole at a position corresponding to the mounting holes, and the seat body having a cover plate for pressing the positioning anchor claws.

[0018] Optionally, the anchoring component further includes a second anchoring component body, the second anchoring component body including a bushing sleeved on the outer periphery of the central tube and an upper rubber sleeve seat, a lower rubber sleeve seat and a rubber sleeve slidably sleeved on the outer periphery of the bushing, the upper rubber sleeve seat and the bushing being connected to the seat body respectively, and the rubber sleeve being disposed between the upper rubber sleeve seat and the lower rubber sleeve seat.

[0019] Optionally, the anchoring component further includes a third anchoring component body, which includes an upper cone, a lower cone, and a slip disposed on the outer periphery of the central tube. The upper cone is connected to the lower rubber sleeve seat, and a protective sleeve is provided on the outer periphery of the upper cone and the lower cone. An opening is provided on the protective sleeve at a position corresponding to the slip, and a first return spring is provided between the protective sleeve and the slip.

[0020] Optionally, the seat locking member includes:

[0021] The rubber sleeve locking claw is connected to the bushing, and the rubber sleeve locking claw slides in engagement with the inner wall of the upper cone;

[0022] An annular locking block is disposed on the inner wall of the upper cone; and configured as follows:

[0023] When the rubber tube is in a compressed state, the rubber tube locking claw engages with the annular locking block to maintain the compressed state of the rubber tube.

[0024] Optionally, the third anchoring component body also includes a locking spring, which is disposed between the protective sleeve and the lower rubber sleeve seat.

[0025] Optionally, the seat locking component further includes a slip ring disposed on the outer periphery of the central tube. The inner side of the slip ring is provided with a second slope surface that matches the first slope surface of the rubber sleeve locking claw, so that the rubber sleeve locking claw can close inward to disengage from the annular locking block during the movement of the rubber sleeve locking claw relative to the slip ring.

[0026] Optionally, the reusable drop-and-reconnect packer further includes a track switching mechanism, the track switching mechanism comprising:

[0027] The track tube is connected to the end of the central tube away from the upper connecting sleeve. The track tube is provided with multiple sealing grooves and unsealing grooves. The multiple sealing grooves and unsealing grooves form a J-shaped track. The upper cone, lower cone and the slip are arranged on the outer periphery of the track tube.

[0028] A switching ring, equipped with a switching pin, is disposed within the J-shaped track and configured as follows:

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

[0030] Optionally, the reusable release and reconnection packer further includes a straightening mechanism, which is sleeved on the outer periphery of the track tube and frictionally engages with the inner wall of the sleeve.

[0031] Optionally, the righting mechanism includes:

[0032] A straightening base is fitted around the outer periphery of the trajectory tube, and the straightening base is connected to the lower cone.

[0033] Multiple straightening blocks are spaced apart on the straightening base 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.

[0034] Optionally, the reusable drop-and-reconnect packer further includes a reverse plugging valve mechanism, the reverse plugging valve mechanism comprising:

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

[0036] The lower connector is connected to the sheath;

[0037] A reverse plugging valve seat is disposed inside the sheath, and the reverse plugging valve seat abuts against the lower connector;

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

[0039] Optionally, the track tube is provided with a lower connecting sleeve on its outer periphery, and the two ends of the lower connecting sleeve are respectively connected to the straightening block base and the protective sleeve.

[0040] Optionally, the support cylinder has a second pressure hole in its wall, the limiting cylinder is configured to move away from the joint in the pressurized state, and a second return spring is provided between the limiting cylinder and the cylinder body.

[0041] The present invention also provides a method for operating a reusable packer, comprising the following steps:

[0042] The reusable packer is lowered into the well. During the lowering of the tubing string, the reusable mechanism pushes the sealing and locking mechanism to move down, causing the mandrel to move to the sealing and locking position. This separates the cavity of the central tube from the annulus between the packer and the casing, and the mandrel is kept in place by the limiting component.

[0043] Continue lowering the tubing. When the tubing reaches the preset position, the anchoring component works, supporting the anchoring component on the inner wall of the sleeve, and maintaining the state of the anchoring component by setting the locking component.

[0044] The limit cylinder moves upward, causing the locking hook on the release and reconnection mechanism to disengage from the control valve seat, completing the unlocking of the reconnection locking claw. The limit cylinder continues to move upward until the locking hook disengages from the first limit groove, the upper tube column, and the release and reconnection mechanism separate from the connector, allowing the release and reconnection packer to perform corresponding operations.

[0045] After the operation is completed, the release and reconnection mechanism is lowered, so that the reconnection locking claw extends into the connector and the tubing is pressed down. After the reconnection locking claw contacts the inner wall of the connector, it retracts, so that the locking hook disengages from the control valve seat. The tubing is pressed down further, and the locking hook is engaged in the first limit groove.

[0046] Lift the tubing string, the limiting component opens, the cavity of the central tube connects with the first and second holes, the upper and lower pressures are balanced, continue to lift the tubing string, the seat locking component opens, the anchoring component resets, and the reusable release packer is moved to the next working position by moving the tubing string.

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

[0048] The packer provided by this invention allows the release and reconnection mechanism to separate from the sealing and locking mechanism during use, preventing disruption to the packer's normal operation. When position adjustment is needed, the release and reconnection mechanism can be connected to the sealing and locking mechanism, enabling the packer to move to the next working position under the action of the release and reconnection mechanism. This avoids frequent drilling trips and improves construction efficiency. Furthermore, the disassembly of the release and reconnection mechanism and the connector requires active force applied towards the limiting cylinder to prevent accidental separation of the release and reconnection mechanism from the sealing and locking mechanism, ensuring construction safety. In addition, during use, the packer maintains the mandrel's position through the limiting component, preventing the mandrel's separation function from failing, and maintains the anchoring structure's state through the locking and fixing component, preventing the anchoring structure from resetting and ensuring the anchoring component's support effect, further ensuring construction safety. In addition, by raising and lowering the tubing string to set the packer, and simultaneously releasing the packer, and then raising the tubing string to set the upper packer, the double-seal single-clamp 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-clamp fracturing tubing string. Therefore, it can avoid tubing erosion between packers, and thus avoid complex downhole problems such as interlayer tubing breakage and perforation failure. Attached Figure Description

[0049] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the reusable reconnectable packer according to an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the structure of a portion of the reusable packer in the setting state according to an embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of the reusable packer after being dropped, according to an embodiment of the present invention.

[0054] Figure 4 This is a schematic diagram of the reusable reconnectable packer described in the first half of an embodiment of the present invention.

[0055] Figure 5 This is a schematic diagram of the structure of the repeatable drop-and-reconnect packer in the lower half of the embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the structure of the release and reconnection mechanism according to an embodiment of the present invention;

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

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

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

[0060] Figure 10 This is a schematic diagram of the structure of the third anchoring member body according to an embodiment of the present invention;

[0061] Figure 11 This is a schematic diagram of the straightening mechanism described in an embodiment of the present invention;

[0062] Figure 12 This is a schematic diagram of the track switching mechanism according to an embodiment of the present invention;

[0063] Figure 13 This is a diagram showing the unfolded J-shaped track of the track switching mechanism according to an embodiment of the present invention;

[0064] Figure 14 This is a schematic diagram of the reverse sealing valve mechanism according to an embodiment of the present invention.

[0065] Explanation of reference numerals in the attached figures

[0066] 1. Central mechanism; 11. Central tube; 111. Spindle valve seat; 12. Upper connecting sleeve; 121. First hole; 122. Second hole; 2. Sealing and locking mechanism; 21. Connector; 211. First limiting groove; 212. Guide groove; 22. Limiting assembly; 221. Second limiting groove; 222. Spindle locking claw; 23. Spindle; 231. Opening; 232. Check valve; 233. Sealing packing; 234. Valve plate; 235. Bypass hole; 3. 31. Release and reconnection mechanism; 31. Support cylinder; 311. Control valve seat; 3111. Sealing sleeve; 32. Cylinder body; 33. Limiting cylinder; 331. Reconnection locking claw; 34. Second return spring; 35. Upper connector; 36. Spring seat; 37. Guide shoe; 38. First sealing ring; 39. Second sealing ring; 4. Anchoring structure; 41. Anchoring component; 4111. First anchoring component body; 4111. Seat body; 4112. Positioning anchor claw; 4113. 4114. Anchor claw return spring; 412. Cover plate; 413. Second anchoring component body; 414. Bushing; 415. Upper rubber sleeve seat; 416. Lower rubber sleeve seat; 417. Rubber sleeve; 418. Third anchoring component body; 419. Upper cone; 412. Lower cone; 413. Slip; 4130. Protective sleeve; 4111. First return spring; 42. Sealing and locking component; 421. Rubber sleeve locking claw; 422. Annular locking block; 43. 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. Straightening mechanism; 61. Straightening base; 62. Straightening block; 63. Compression spring; 64. Straightening pressure ring; 7. Reverse sealing valve mechanism; 71. Protective sleeve; 72. Lower connector; 73. Reverse sealing valve seat; 74. Valve disc; 75. Torsion spring; 8. Lower connecting sleeve. Detailed Implementation

[0067] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments and features of the present invention can be combined with each other.

[0068] The following description sets forth many specific details in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments described in the specification are only some, not all, of the embodiments of the invention.

[0069] Combination Figures 1 to 5 As shown, the reusable release and reconnect packer provided in this embodiment of the invention includes a central mechanism 1, a sealing and locking mechanism 2, a release and reconnect 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. The side wall of the upper connecting sleeve 12 is provided with a first hole 121 and a second hole 122 communicating with the cavity of the central tube 11. Specifically, the central tube 11 has corresponding first and second ends, so as to... 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 can be directly connected to the upper connecting sleeve 12, or it can be indirectly connected to the first end of the central tube 11 and the upper connecting sleeve 12 by means of other mechanisms.

[0071] Combination Figure 4 and Figure 7 As shown, the sealing and locking mechanism 2 includes a connector 21, a limiting component 22, and a spindle 23 connected to the connector 21. Part of the spindle 23 extends into the upper connecting sleeve 12. The connector 21 can move the spindle 23 between an unsealed position and a sealed and locked position, allowing the spindle 23 to communicate with or separate the first hole 121 and the second hole 122 from the cavity of the central tube 11. The limiting component 22 is configured to restrict or release the spindle 23 in the sealed and locked position. One end of the spindle 23 extends into the connector 21 and is threadedly connected to it to increase ease of assembly and disassembly. It can also be further tightened with a locking screw to increase the connection's strength. The other end of the spindle 23 extends into the upper connecting sleeve 12, and the extended end of the spindle 23 has a stepped surface. The upper connecting sleeve 12 is fitted onto the stepped surface of the spindle 23 to prevent the spindle 23 from detaching from the upper connecting sleeve 12.

[0072] Combination Figure 4 and Figure 6 As shown, the release and reconnection mechanism 3 includes a support cylinder 31, a cylinder body 32 sleeved around the outer periphery of the support cylinder 31, and a limiting cylinder 33 disposed between the cylinder body 32 and the support cylinder 31. The end of the support cylinder 31 extends out of the cylinder body 32, and a limiting ring is provided on the outer periphery of the support cylinder 31 to restrict the movement range of the limiting cylinder 33 and prevent it from extending beyond the cylinder body 32. The end of the limiting cylinder 33 is provided with a reconnection locking claw 331 with a locking hook, the locking hook being located on the outer side of the end of the reconnection locking claw 331. A control valve seat 311 is threadedly connected to 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 move along its axial direction, so that the locking hook can be supported on the outer periphery of the control valve seat 311 or disengaged from the control valve seat 311. The connector 21 has a first limiting groove 211 inside that matches 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 locking hook of the retraction locking claw 331 is supported on the outside of the control valve seat 311 to prevent the retraction locking claw 331 from closing inward.

[0074] When the locking hook needs to be inserted into the first limiting groove 211, the limiting cylinder 33 needs to be moved away from the control valve seat 311 so that the locking hook disengages from the control valve seat 311. At this time, the retraction locking claw 331 is inserted into the connector 21. The retraction locking claw 331 can retract under the pressure of the connector 21 until the locking hook is inserted into the first limiting groove 211. Then the retraction locking claw 331 unfolds and the limiting cylinder 33 resets, so that the locking hook is supported on the outer periphery of the control valve seat 311, preventing the retraction locking claw 331 from accidentally disengaging and ensuring the safety of use.

[0075] When it is necessary to disengage the release and reconnection mechanism 3 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 disengages from the control valve seat 311 (the locking hook is always within the first limiting groove 211). Then, by lifting the release and reconnection mechanism 3, the locking hook disengages from the first limiting groove 211, completing the separation process of the release and reconnection mechanism 3. The operation is convenient.

[0076] Anchoring structure 4 is disposed on the outer periphery of central tube 11, including anchoring member 41 and setting and locking member 42. Anchoring member 41 is configured to be supported on the inner wall of sleeve or to be separated from sleeve. Setting and locking member 42 is configured to maintain the state of anchoring member 41 when it is supported on the inner wall of sleeve. Specifically, when the packer is in the setting and locking state, the anchoring member 41 can be deployed by lowering the tube column to support it on the inner wall of sleeve. At this time, the setting and locking member 42 can maintain the state of anchoring member 41, ensuring the support effect of 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 and locking mechanism 2 is in the locked state, as... Figure 2 As shown, the first hole 121 corresponds to the bypass hole 235 on the mandrel 23, connecting the inside and outside of the packer; when the sealing locking mechanism 2 is not locked, that is, when the mandrel 23 is completely disengaged from the mandrel valve seat 111 described below, as Figure 7 As shown, the second hole 122 corresponds perfectly to the opening 231 on the shaft, connecting the inside and outside of the packer. The first hole 121 and the second hole 122 serve the same purpose: to provide a reverse circulation channel for the packer. The two holes ensure that, under any operating condition, one of the holes on the packer's spindle 23 will perfectly correspond to the bypass hole 235 on the spindle 23, preserving the largest possible reverse circulation channel and minimizing the erosion of the packer's spindle 23 by the liquid.

[0078] In the use state, the release and reconnection mechanism 3 of the packer provided by this invention is separated from the sealing and locking mechanism 2 to avoid affecting the normal use of the packer. When it is necessary to adjust its own position, the release and reconnection mechanism 3 can be connected to the sealing and locking mechanism 2, so that the packer can move 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 connector 21 of this application requires the active application of force towards the limiting cylinder 33 to prevent the release and reconnection mechanism 3 from accidentally disengaging from the sealing and locking mechanism 2, ensuring the safety of construction. In addition, in the use state, the packer can maintain the position of the mandrel 23 through the limiting component 22 to prevent the separation function of the mandrel 23 from failing, and maintain the state of the anchoring structure 4 through the seat locking component 42 to prevent the anchoring structure 4 from resetting, ensuring the support effect of the anchoring component 41, and further ensuring the safety of construction. In addition, by raising and lowering the tubing string to set the packer, and simultaneously releasing the packer, and then raising the tubing string to set the upper packer, the double-seal single-clamp 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-clamp fracturing tubing string. Therefore, it can avoid tubing erosion between packers, and thus avoid complex downhole problems such as interlayer tubing breakage and perforation failure.

[0079] In some implementations, such as Figure 7 As shown, the limiting component 22 includes a second limiting groove 221 disposed on the outer periphery of the portion of the spindle 23 extending into the upper connecting sleeve 12, and a spindle locking claw 222 disposed on the inner wall of the upper connecting sleeve 12, wherein the second limiting groove 221 and the spindle locking claw 222 are matched. When the spindle 23 is in the sealed locked position, the spindle locking claw 222 engages with the second limiting groove 221. When the release and retraction mechanism 3 is lifted, the release and retraction mechanism 3 can move the spindle 23 upwards through the connector 21, thereby separating the spindle locking claw 222 from the spindle 23 and unlocking the spindle 23. This design of the limiting component 22 is simple in structure, and the separation or engagement process can be completed simply by lifting or lowering the release and retraction mechanism 3, making it convenient to operate.

[0080] The mandrel 23 has an opening 231 in its middle, communicating with the cavity of the central tube 11. A one-way valve 232 is installed inside the opening 231 to allow unidirectional fluid flow. A bypass hole 235 communicating with the opening 231 is provided on the side wall of the upper connecting sleeve 12. When the mandrel 23 is not in the sealed locking position, the bypass hole 235 is opposite to the second hole 122, and the first hole 121 communicates with the cavity of the central tube 11, resulting in balanced pressure. When the mandrel 23 moves to the sealed locking position, the bypass hole 235 is opposite to the second hole 122, and the mandrel 23 blocks the end of the central tube 11, isolating the first hole 121 from the cavity of the central tube 11. This design reduces the space occupied by the mandrel 23, making the overall structure more compact. Furthermore, whether in the sealed or unsealed state, the positions of the first hole 121 or the second hole 122 and the bypass hole 235 are perfectly aligned, maximizing fluid flow and meeting design requirements.

[0081] Further optimized, the outer periphery of the end of the mandrel 23 is provided with a sealing packing 233, and the end of the central tube 11 is provided with a mandrel valve seat 111. When the mandrel 23 moves to the sealing locking position, the sealing packing 233 fits against the inner wall of the mandrel valve seat 111 to form a seal, thereby ensuring the tightness of the connection and the isolation effect. The end of the mandrel 23 is threadedly connected with a packing lock cap, and the sealing packing 233 is fitted onto the outer periphery of the sealing packing 233 to increase the ease of installation of the sealing packing 233. The sealing packing 233 can be tightened by screwing on the packing lock cap to ensure its fixation. The inside of the packing lock cap is provided with a tapered hole, and a one-way valve 232 is installed at the position of the tapered hole to support the one-way valve 232 through the slope of the tapered hole. The function of the one-way valve 232 is to prevent the upper liquid from entering the lower part of the packer after the sealing locking mechanism 2 has locked.

[0082] Furthermore, a valve plate 234 can be provided inside the opening 231 of the mandrel 23. The valve plate 234 is supported on the inner wall of the mandrel 23 by the end of the packing cap, preventing 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 one-way valve 232, so as to limit the valve ball within the tapered hole of the packing cap.

[0083] In some implementations, such as Figure 8As shown, the anchoring component 41 includes a first anchoring component body 411, which includes a seat 4111 disposed on the outer periphery of the central tube 11. The seat 4111 has multiple mounting holes, and positioning anchor claws 4112 are disposed inside the mounting holes. The positioning anchor claws 4112 are connected to the bottom wall of the mounting holes via anchor claw return springs 4113. A first pressure hole is provided at a position corresponding to the mounting hole on the seat 4111. A cover plate 4114 for pressing the positioning anchor claws 4112 is provided on the seat 4111. In the set-sealed state, pressure can be applied towards the inside of the mounting hole through the first pressure hole. At this time, the internal pressure of the positioning anchor claw 4112 is higher than the external pressure, i.e., when the internal pressure of the packer is higher than the external pressure, the positioning anchor claw 4112 is activated. Under the action of the internal and external pressure difference, the positioning anchor claw 4112 extends outward and anchors itself to the inner wall of the sleeve. In the unsealed state, the positioning anchor claw 4112 can be reset by the action of the anchor claw return springs 4113. The mounting holes can be blind holes, and there are 6 blind holes. The 6 blind holes are divided into two rows and symmetrically distributed along the circumferential direction of the central tube 11. The outer arc surface of the positioning anchor claw 4112 and the seat 4111 is designed with grooves. A cover plate 4114 is installed on the groove to press the positioning anchor claw 4112 and the anchor claw return spring 4113, and the cover plate 4114 is fixed by fastening screws.

[0084] Specifically, the end of the seat body 4111 extends beyond the first end of the central 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 disassembly and assembly. An O-ring seal is provided between the spindle valve seat 111 and the inner wall of the extended end of the seat body 4111 to ensure a tight connection. The upper connecting sleeve 12 is threadedly connected to the outer circumference of the extended end of the seat body 4111, and part of the spindle locking claw 222 extends between the seat body 4111 and the upper connecting sleeve 12. The upper connecting sleeve 12, part of the spindle locking claw 222, and the extended end of the seat body 4111 are further secured by anti-rotation screws to ensure a firm connection.

[0085] In other implementations, such as Figure 9As shown, the anchoring component 41 also includes a second anchoring component body 412. The second anchoring component body 412 includes a bushing 4121 sleeved on the outer periphery of the central tube 11, and an upper rubber sleeve seat 4122, a lower rubber sleeve seat 4123, and a rubber sleeve 4124 slidably sleeved on the outer periphery of the bushing 4121. The bushing 4121 is clearance-fitted with the central tube 11 to form a hydraulic channel communicating with the first pressurization hole. This hydraulic channel is connected to the lower part of the packer. The pressure at the lower part of the packer is generally higher than the pressure at the upper part of the packer. At this time, the internal pressure of the packer is introduced into the interior of the positioning anchor claw 4112. The external environment of the positioning anchor claw 4112 is annular with 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 is activated and extends to play the role of anchoring the tube column. The positioning anchor claw 4112 is a conventional technology in the field, so its working principle is not described in detail.

[0086] It is worth noting that the third anchoring component body 413 is activated when the packer is set. After the third anchoring component body 413 is activated, it ensures that the tubing will not move up or down. If the lower pressure of the packer is higher than the upper pressure after the third anchoring component body 413 is activated, the first anchoring component body 411 is activated to further ensure that the tubing will not move up or down. If the lower pressure of the packer is not higher than the upper pressure, the first anchoring component body 411 will not be activated, and it will have no other effect on the tubing.

[0087] The upper rubber sleeve seat 4122 and the bushing 4121 are respectively connected to the seat body 4111. The rubber sleeve 4124 is disposed between the upper rubber sleeve seat 4122 and the lower rubber sleeve seat 4123, and both ends of the rubber sleeve 4124 are respectively in close contact with the upper rubber sleeve seat 4122 and the lower rubber sleeve seat 4123. In this design, when the tubing is lowered, the tubing is pushed to move by the sealing lock and the first anchoring component body 411. At this time, since the rubber sleeve 4124 can be compressed, the bushing 4121 moves relative to the upper rubber sleeve seat 4122, the lower rubber sleeve seat 4123 and the rubber sleeve 4124. During this process, the rubber sleeve 4124 is compressed and expanded outward to support itself on the inner wall of the sleeve, thus playing a positioning role.

[0088] Specifically, the end of the base 4111 facing the upper rubber sleeve seat 4122 is provided with a partition plate. The bushing 4121 is located inside the partition plate, and the upper rubber sleeve seat 4122 is wrapped around the outside of the partition plate. The upper rubber sleeve seat 4122 is threadedly connected to the partition plate, increasing the convenience of disassembly and assembly. In addition, the inner ring of the upper rubber sleeve seat 4122 extends out 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. The end of the bushing 4121 is provided with an annular baffle. The annular baffle can slide within this gap, and the movement range of the annular baffle is limited by the inner ring of the upper rubber sleeve seat 4122 to avoid excessive stroke.

[0089] In other implementations, such as Figure 10 As shown, the anchoring member 41 also includes a third anchoring member body 413, which includes an upper cone 4131, a lower cone 4132 disposed on the outer periphery of the central tube 11, and a catch 4133 disposed between the upper cone 4131 and the lower cone 4132. The third anchoring member body 413 can be directly disposed on the outer periphery of the central tube 11, or it can be disposed on the outer periphery of the central tube 11 through other structures. The upper cone 4131 is connected to the lower rubber sleeve seat 4123 so that the lower rubber sleeve seat 4123 can push the upper cone 4131 to move. The outer periphery of the upper cone 4131 and the lower cone 4132 is provided with a protective sleeve. The protective sleeve is fitted 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 and the lower cone 4132 are threadedly connected. The protective sleeve is provided with an opening at the position corresponding to the slip 4133. A first return spring 4135 is provided between the protective sleeve and the slip 4133.

[0090] Specifically, the upper cone 4131 and lower cone 4132 are arranged with their slopes facing each other. Multiple slips 4133 are installed on the outer circumference of the support mechanism (the track tube 51 described below). Slopes are also provided at positions corresponding to the slips 4133 and the upper and lower cones 4131 and 4132, ensuring that the contact surfaces between the slips 4133 and the upper and lower cones 4131 and 4132 are sloped. A first return spring 4135 is provided between the middle 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 packer drilling. During the lowering of the tubing, the upper cone 4131 can be moved by the lower rubber sleeve seat 4123. The slips 4133 move outward under the action of the slope to extend the opening, and are supported on the inner wall of the sleeve, providing a limiting effect. After the external force disappears, the 4133 slip is retracted into the inside of the protective sleeve 4134 under the action of the first return spring 4135 to contact the limit, at which point the upper cone 4131 is reset.

[0091] Further optimization, such as Figure 9 As shown, the third anchoring component body 413 also includes a locking spring 423, which is disposed between the protective sleeve 4134 and the lower rubber sleeve seat 4123, and is sleeved on the outer periphery of the upper cone 4131. When the third anchoring component body 413 is anchored, the lower cone 4132 moves upward, causing the protective sleeve 4134 to compress the locking spring 423. Therefore, when the third anchoring component body 413 is anchored, the locking spring 423 is always in a compressed state. When the packer is lifted, the tubing drives the upper cone 4131 to move upward, and at the same time, the locking spring 423 pushes the protective sleeve 4134 downward. The protective sleeve 4134 drives the lower cone 4132 downward. Therefore, the upper cone 4131 moves upward and the lower cone 4132 moves downward. The anchor claw 4133 returns to its original state under the action of the first return spring 4135, releasing the anchoring state.

[0092] The anchoring member 41 of this application includes a first anchoring member body 411, a second anchoring member body 412, and a third anchoring member body 413, distributed at the upper and lower positions of the reusable packer. This ensures that the reusable packer is evenly stressed, guaranteeing its setting effect and ensuring that it can withstand both downward and upward pressure during use. Specifically, after the packer is set, the rubber sleeve 4124 seals the annulus between the tubing and the sleeve, and the mandrel 23 inside the packer seals the annulus inside the tubing. Therefore, after the packer is set, it forms a barrier, preventing communication between the upper and lower parts of the packer.

[0093] In some implementations, such as Figure 9 As shown, the locking member 42 includes a rubber sleeve locking claw 421 and an annular locking block 422. The rubber sleeve locking claw 421 is connected to the bushing 4121 and slides against 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 sleeve 4124 is in a compressed state, the rubber sleeve locking claw 421 and the annular locking block 422 engage, thus maintaining the compressed state of the rubber sleeve 4124.

[0094] Specifically, the end of the rubber sleeve locking claw 421 is threaded to the outer circumference of the end of the bushing 4121 to increase the convenience of disassembly and assembly. The inner wall of the lower rubber sleeve seat 4123 is machined with double steps to accommodate the end of the rubber sleeve locking claw 421 and the end of the upper cone 4131 respectively, making the structure more compact. The locking hook of the rubber sleeve 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 sleeve locking claw 421 is provided with a ramp surface. When the rubber sleeve locking claw 421 moves relative to the inner wall of the upper cone 4131, and the locking hook of the rubber sleeve locking claw 421 contacts the inner wall of the annular locking block 422, the rubber sleeve locking claw 421 retracts inward under the action of the ramp surface, so that it can move to the other side of the annular locking block 422 to realize the engagement of the rubber sleeve locking claw 421 and the annular locking block 422. With this design, when the rubber tube 4124 is in a compressed state and the release and reconnection mechanism 3 is disengaged, the rubber tube locking claw 421 and the annular locking block 422 can cooperate to prevent the rubber tube 4124 from resetting, thereby ensuring the anchoring effect of the rubber tube 4124 and ensuring safe construction.

[0095] In a further optimized manner, the seat locking component 42 also includes a slip ring 424, which is disposed 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 tube locking claw 421, so that the rubber tube locking claw 421 can close inward to disengage from the annular locking block 422 during the movement of the rubber tube locking claw 421 relative to the slip ring 424.

[0096] Specifically, when unsealing is required, the tube column is lifted. Due to the engagement between the rubber sleeve locking claw 421 and the annular locking block 422, the slip ring 424 on the central tube 11 has an upward movement tendency. This, through the cooperation of the first and second inclined surfaces, pushes the rubber sleeve locking claw 421 inward, so that the rubber sleeve locking claw 421 and the annular locking block 422 actively disengage. This reduces the damage caused by the hard contact between the rubber sleeve locking claw 421 and the annular locking block 422, and ensures the service life of the rubber sleeve locking claw 421 and the annular locking block 422.

[0097] In this invention, the annular space between the outside of the tubing and the inside of the casing is sealed by a rubber sleeve 4124, and the inside of the packer is sealed by a mandrel 23, ensuring reliable sealing performance. The inner and outer seals are locked by a limiting component 22 and a setting and locking component 42, respectively, ensuring that the packer will not fail to unlock midway due to unexpected circumstances during the sealing process. That is, after the inner and outer seals are formed, the packer at this point acts like a bridge plug after being released and set, sealing the lower well section, allowing construction operations to be carried out on the upper well section sealed by the packer.

[0098] Combination Figure 12 and Figure 13As shown, the reusable release and reconnection packer of this application also includes a track switching mechanism 5, which includes a track tube 51 and a switching ring 52. The track tube 51 is threaded to the end of the center tube 11 away from the upper connecting sleeve 12, increasing the convenience of disassembly and assembly. The track tube 51 is provided with multiple setting grooves 511 and unsetting grooves 512, wherein the length of the setting groove 511 is greater than the length of the unsetting groove 512, and the multiple setting grooves 511 and unsetting grooves 512 form a J-shaped track. The upper cone 4131, the lower cone 4132, and the slip 4133 are arranged on the outer periphery of the track tube 51 to make the overall structure more compact. The switching ring 52 is provided with switching pins 521. The switching ring 52 has two symmetrically distributed through holes machined radially. There are two switching pins 521, which are respectively set in the two through holes. The switching ring 52 and the switching pins 521 are set in the J-shaped track. When the track tube 51 is lifted, the switching ring 52 can rotate so that the switching pins 521 can switch between the sealing groove 511 and the unsealing groove 512.

[0099] like Figure 11 As shown, the reusable packer of this application also includes a centering mechanism 6, which is sleeved on the outer periphery of the trajectory tube 51 and frictionally engages with the inner wall of the sleeve. The centering mechanism 6 is used to ensure that the packer is in a centered 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 quickly.

[0100] In some embodiments, the straightening mechanism 6 includes a straightening base 61 and multiple straightening blocks 62. The straightening base 61 is sleeved on the outer periphery of the track tube 51 and is threadedly connected to the lower cone 4132. Multiple straightening blocks 62 are spaced apart on the straightening base 61 along the circumferential direction of the central tube 11, and the straightening blocks 62 extend beyond the straightening base 61. A compression spring 63 is provided between the straightening blocks 62 and the straightening base 61 to push the straightening blocks 62 out of the straightening base 61. The straightening blocks 62 are always in an extended state under the support of the preload provided by the compression spring 63, so that the straightening blocks 62 can be supported on the inner wall of the sleeve. Multiple blind holes are provided on the straightening blocks 62, and some of the compression springs 63 are located within the blind holes to limit the compression springs 63 and restrict their compression direction. The elastic force of the compression springs 63 can be designed according to actual needs.

[0101] Furthermore, the straightening mechanism 6 also includes a straightening pressure ring 64, which is sleeved on the outer periphery of the track tube 51. The end of the straightening pressure ring 64 is threadedly connected to the straightening base 61 and extends into the straightening base 61, so that the end of the straightening pressure ring 64 can press against one edge of the straightening block 62. A pressure plate is provided at a position on the straightening base 61 corresponding to the other edge of the straightening block 62. Correspondingly, both ends of the straightening block 62 are provided with bosses, which contact the end of the straightening pressure ring 64 and the pressure plate, respectively, to ensure the limiting effect of the straightening block 62 and prevent the straightening block 62 from detaching from the straightening base 61. The compression spring 63 is in a compressed state within the straightening base 61. By setting the straightening pressure ring 64, the components of the straightening mechanism 6 are designed separately, increasing the convenience of disassembly, assembly, and processing.

[0102] like Figure 14 As shown, the reusable packer of this application also includes a reverse sealing valve mechanism 7, which includes a sleeve 71, a lower connector 72, a reverse sealing valve seat 73, and a valve disc 74. The sleeve 71 is connected to the end of the track tube 51. The lower connector 72 is connected to the sleeve 71. The reverse sealing valve seat 73 is disposed inside the sleeve 71 and abuts against the lower connector 72. The valve disc 74 is mounted on the reverse sealing valve seat 73 by a torsion spring 75.

[0103] Specifically, the inner wall of the sleeve 71 is machined with a stepped surface. The reverse sealing valve seat 73 is installed inside the sleeve 71, and the upper end of the reverse sealing valve seat 73 contacts the stepped surface of the inner wall of the sleeve 71. A reverse sealing valve O-ring is installed between the reverse sealing valve seat 73 and the sleeve 71 to ensure a tight connection. The lower end face of the reverse sealing valve seat 73 contacts the upper end face of the lower connector 72. The lower connector 72 is threadedly connected to the sleeve 71. A valve disc 74 is installed on the reverse sealing valve seat 73, and a torsion spring 75 connects the reverse sealing valve seat 73 and the valve disc 74.

[0104] In use, valve disc 74 is generally in the open state under the spring force of torsion spring 75. When the liquid pressure in the lower part of the packer is higher than the pressure in the upper part, valve disc 74 overcomes the spring force of torsion spring 75 under the action of pressure difference. Valve disc 74 rotates 90° and contacts valve seat 73 to form a blocking state. At this time, valve disc 74 of reverse blocking valve mechanism 7 bears the force of liquid in the lower part of the packer. This force is transmitted by reverse blocking valve mechanism 7 to the sleeve 71 connected to it, and then the force is further transmitted to the lower cone 4132, further squeezing the slip 4133 to play an auxiliary role in the third anchoring member body 413.

[0105] Further optimized, the track tube 51 is provided with a lower connecting sleeve 8 on its outer periphery. Both ends of the lower connecting sleeve 8 are connected to the base of the straightening block 62 and the protective sleeve 71, respectively, to increase the strength 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 protective sleeve 71. The lower connecting sleeve 8 presses against the end face of the switching ring 52, ensuring that the switching ring 52 moves along the J-shaped track.

[0106] In some embodiments, the support cylinder 31 has a second pressurization hole in its cylinder wall, the limiting cylinder 33 is configured to move away from the connector 21 under pressurization, 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 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 pressure hole away from the first sealing ring 38, so that a pressure injection space communicating with the second pressure injection hole is formed between the first sealing ring 38 and the second sealing ring 39. When pressure is injected into the pressure injection space, the pressure will push the annular push plate to move away from the connector 21, causing the reconnection locking claw 331 to disengage from the control valve seat 311. After the release reconnection mechanism 3 disengages from the connector 21, the pressure injection stops, and the reconnection locking claw 331 resets under the action of the second return spring 34. This design allows the reconnection locking claw 331 to disengage from the control valve seat 311 by applying pressure, avoiding misoperation and effectively ensuring the safety of construction.

[0108] Specifically, the release and reconnection mechanism 3 of this application further includes an upper connector 35 connected to the tubing column. The cylinder 32 is threadedly connected to the outer wall of the upper connector 35, and the support cylinder 31 is threadedly connected to the inner wall of the upper connector 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 locking claw 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 cylinder 32, and the guide shoe 37 is used to control the extension length of the reconnection locking claw 331. A sealing sleeve 3111 is provided on the outer periphery of the control valve seat 311 to increase the tightness of the connection between the control valve seat 311 and the connector 21.

[0109] It is understood that sealing rings can be reasonably set between the components that need to be sealed in this application to ensure a sealed connection between the corresponding components.

[0110] The connector 21 of this application has a guide groove 212 at its end. The guide groove 212 is open and is connected to the first limiting groove 211 through a transition groove. During the insertion of the reconnecting locking claw 331 into the connector 21, the reconnecting locking claw 331 is preferentially drawn inward under the action of the guide groove 212, so that the locking hook of the reconnecting locking claw 331 can be inserted into the first limiting groove 211, increasing the convenience of the reconnecting locking claw 331 insertion. In addition, the two end side walls of the first limiting groove 211 are provided with slopes to facilitate the locking hook to disengage from the first limiting groove 211.

[0111] The present invention also provides a method for operating the above-mentioned reusable packer, comprising the following steps:

[0112] In step S1, the reusable packer is lowered into the well. During the lowering of the tubing string, the reusable mechanism 3 pushes the sealing locking mechanism 2 downward, causing the mandrel 23 to move to the sealing locking position, separating the cavity of the central tube 11 from the annulus between the packer and the casing, and maintaining the position of the mandrel 23 through the limiting component 22.

[0113] Specifically, during the insertion of the tubing, due to the friction between the straightening mechanism 6 and the inner wall of the sleeve, the packer's connector 21 pushes the mandrel 23 downward. The mandrel 23 contacts the mandrel valve seat 111 to form a seal, thus separating the cavity of the central tube 11 from the annulus between the packer and the sleeve. The mandrel locking claw 222 locks with the second limiting groove 221 on the mandrel 23, and the sealing locking mechanism 2 is activated.

[0114] Step S2: Continue lowering the pipe column. When the pipe column is lowered to the preset position, the anchoring component 41 works, so that the anchoring component 41 is supported on the inner wall of the sleeve, and the anchoring component 41 is kept in the state by the seated locking component 42.

[0115] Specifically, the tube string continues to be lowered, overcoming the friction between the straightening mechanism 6 and the inner wall of the sleeve to reach the designed position. The tube string is then lifted, causing the packer's track switching mechanism 5 to switch to the packer's setting track (the switching pin 521 slides into the setting groove 511). As the tube 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, remains stationary, while the upper part of the straightening mechanism 6 moves downwards, i.e., the upper cone 4131 moves downwards. The slip 4133 is compressed, extending out of the protective sleeve and anchoring onto the sleeve, activating the lower anchoring mechanism. The tube string continues to lower, compressing the rubber sleeve 4124 to form a seal with the inner wall of the sleeve. The rubber sleeve locking claw 421 engages with the annular locking block 422, activating the locking function of the setting locking component 42, and the packer completes setting. The structural form of the setting locking component 42 has been described above and will not be elaborated upon here.

[0116] In step S3, the limiting cylinder 33 moves upward, causing the locking hook on the release and reconnection mechanism 3 to disengage from the control valve seat 311, thus unlocking the reconnection locking claw 331. The limiting cylinder 33 continues to move upward until the locking hook disengages from the first limiting groove 211, and the upper tube column, release and reconnection mechanism 3, and connector 21 separate, allowing the release and reconnection packer to perform corresponding operations.

[0117] Specifically, pressure is applied by pumping fluid into the tubing string, causing the limiting cylinder 33 to rise under hydraulic pressure. A steel ball of suitable size is inserted into the tubing string, resting on the conical surface of the control valve seat 311, forming a seal. Pressure is pumped into the tubing string from the wellhead, and the pressure enters the injection space through the channel in the support cylinder 31 and the second pressurization hole. The resulting pressure difference pushes the reconnection locking claw 331 upwards and the support cylinder 31 downwards, causing the reconnection locking claw 331 to disengage from the support cylinder 31, thus releasing the forced lock between the reconnection locking claw 331 and the connector 21. At this time, the internal pressure of the release reconnection mechanism 3 pushes the reconnection locking claw 331 upwards, completely releasing the lock between the reconnection locking claw 331 and a limiting groove. The tubing string continues to be lifted, causing the entire release reconnection mechanism 3 to move upwards, disengaging the release reconnection mechanism 3 from the connector 21, and the packer is successfully released. Furthermore, after the release and retraction mechanism 3 disengages, the retraction lock 331 and the support cylinder 31 return to their original positions under the spring force of the second reset spring 34.

[0118] Step S4: After the operation is completed, the release and reconnection mechanism 3 is lowered, so that the reconnection locking claw 331 extends into the connector 21 and the tube column is pressed down. After the reconnection locking claw 331 contacts the inner wall of the connector 21, it retracts, so that the locking hook disengages from the control valve seat 311. The tube column is pressed down further, and the locking hook is engaged in the first limit groove 211.

[0119] Specifically, the release and reconnection mechanism 3 is lowered to the setting position of the packer. The release and reconnection mechanism 3 is lowered, and the reconnection locking claw 331 forms a compression with the inner wall of the connector 21 to stop the action. The release and reconnection mechanism 3 is pressed down further, and the reconnection locking claw 331 is forced to retract and disengage from the support cylinder 31. The support cylinder 31 continues to descend into the interior of the connector 21. After the support cylinder 31 is completely disengaged from the reconnection locking claw 331, the reconnection locking claw 331 retracts inward under the pressure of the tubing, reducing the overall outer diameter of the locking claw 331. The tubing continues to descend, and the retracted reconnection locking claw 331 enters the first limiting groove 211 through the inner wall of the connector 21. After the locking claw 311 enters the interior of the first limiting groove 211, the support cylinder 31 returns to its original position under the spring force of the second reset spring 34. The support cylinder 31 and the reconnection locking claw 331 are forcibly locked again to prevent the reconnection locking claw 331 from accidentally unlocking the connector 21. The release reconnection mechanism 3 and the packer are reconnected.

[0120] Step S5: Lift the tubing column, the limiting component 22 opens, the cavity of the central tube 11 connects with the first hole 121 and the second hole 122, the upper and lower pressures are balanced, continue to lift the tubing column, the seat locking component 42 opens, the anchoring component 41 resets, and the reusable release packer is moved to the next working position by moving the tubing column.

[0121] Specifically, when the tubing is lifted, the limiting component 22 first unlocks and disengages under a small force, connecting the upper and lower annular spaces of the packer and balancing the pressures (when the tubing is lowered to set the packer, the rubber sleeve 4124 is compressed and set, sealing the annular space outside the packer; the internal mandrel 23 and mandrel valve seat 111 are sealed and locked; a one-way valve 232 is installed inside the mandrel 23, preventing liquid in the annular space outside the packer from entering below the packer through the first hole 121 and the second hole 122). When the tubing is lifted to release the packer, the seal between the internal mandrel 23 and the mandrel valve seat 111 is first released, allowing liquid in the upper part of the packer to connect with the space below the packer through the first hole 121 and the second hole 122, balancing the pressure in the upper part of the rubber sleeve 4124 with the pressure in the lower part of the packer, preventing the packer from encountering resistance during lifting). The anchor claw is then retracted under the force of the return spring. As the tubing continues to rise, the 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 disengaged. The tubing moves upward, the rubber sleeve 4124 is released from compression, the upper cone 4131 moves upward, and the slip 4133 retracts under the action of the first return spring 4135. The lower anchoring mechanism is disengaged, and the packer is unsealed. Continuing to lift and drag the tubing to the next designed position, repeating the above steps, allows for movement of the tubing to multiple positions.

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

[0123] This application can effectively solve the problem of frequent drilling and adjustment of the spacing between the two packers in the double-packer single-packer fracturing process, and the severe erosion of the tubing between the two packers. It realizes the free spacing double-packer single-packer fracturing technology without interlayer connecting tubing, which can effectively improve the efficiency of on-site construction operations.

[0124] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0125] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the 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 invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A reusable, drop-and-reconnect packer, characterized in that, include: 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) communicating with the cavity of the central tube (11); The sealing and locking mechanism (2) includes a connector (21), a limiting component (22), and a spindle (23) connected to the connector (21). Part of the spindle (23) extends into the interior of the upper connecting sleeve (12). The connector (21) can drive the spindle (23) to move between the unsealed position and the sealing and locking position, so that the spindle (23) communicates with or separates the first hole (121) and the second hole (122) from the cavity of the central tube (11). The limiting component (22) is configured to restrict or release the spindle (23) when it is in the sealing and locking position. The release and 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) disposed between the cylinder body (32) and the support cylinder (31). The end of the limiting cylinder (33) is provided with a reconnection locking claw (331) with a locking hook. The end of the support cylinder (31) is provided with a control valve seat (311). 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 disengaged from the control valve seat (311). The inside of the connector (21) is provided with a first limiting groove (211) that matches 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). as well as An anchoring structure (4) is disposed on the outer periphery of the central tube (11) and includes an anchoring member (41) and a seat 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. The seat 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 reusable reconnectable packer according to claim 1, characterized in that, The limiting component (22) includes: A second limiting groove (221) is provided on the outer periphery of the mandrel (23); and The spindle locking claw (222) is provided on the inner wall of the upper connecting sleeve (12) and configured as follows: When the mandrel (23) is in the sealed locking position, the mandrel locking claw (222) engages with the second limiting groove (221).

3. The reusable reconnectable packer according to claim 1, characterized in that, The mandrel (23) has an opening (231) in its middle portion that communicates with the cavity of the central tube (11). A one-way valve (232) is provided inside the opening (231). A bypass hole (235) communicating with the opening (231) is provided on the side wall of the upper connecting sleeve (12), and is configured as follows: When the mandrel (23) is not moved to the unsealed position, the bypass hole (235) is opposite to the second hole (122), and the first hole (121) is connected to the cavity of the central tube (11); When the mandrel (23) moves to the sealed locking position, the bypass hole (235) is opposite to the second hole (122), and the mandrel (23) blocks the end of the central tube (11) to isolate the first hole (121) from the cavity of the central tube (11).

4. The reusable reconnectable packer according to claim 3, characterized in that, The mandrel (23) has a sealing packing (233) on its outer periphery and the center tube (11) has a mandrel valve seat (111) at its end. When the mandrel (23) moves to the sealing lock position, the sealing packing (233) fits against the inner wall of the mandrel valve seat (111) to form a seal.

5. The reusable reconnectable packer according to claim 1, characterized in that, The anchoring component (41) includes a first anchoring component body (411), which includes a seat (4111) disposed on the outer periphery of the central tube (11). The seat (4111) has a plurality of mounting holes, and the mounting holes are provided with positioning anchor claws (4112). The positioning anchor claws (4112) are connected to the bottom wall of the mounting holes by anchor claw return springs (4113). The seat (4111) is provided with a first pressure hole at a position corresponding to the mounting holes. The seat (4111) is provided with a cover plate (4114) for pressing the positioning anchor claws (4112).

6. The reusable drop-and-reconnect packer according to claim 5, characterized in that, The anchoring component (41) further includes a second anchoring component body (412), which includes a bushing (4121) sleeved on the outer periphery of the central tube (11) and an upper rubber sleeve seat (4122), a lower rubber sleeve seat (4123), and a rubber sleeve (4124) slidably sleeved on the outer periphery of the bushing (4121). The upper rubber sleeve seat (4122) and the bushing (4121) are respectively connected to the seat body (4111), and the rubber sleeve (4124) is disposed between the upper rubber sleeve seat (4122) and the lower rubber sleeve seat (4123).

7. The reusable drop-and-reconnect packer according to claim 6, characterized in that, The anchoring component (41) further includes a third anchoring component body (413), which includes an upper cone (4131), a lower cone (4132) disposed on the outer periphery of the central tube (11), and a slip (4133) disposed between the upper cone (4131) and the lower cone (4132). The upper cone (4131) is connected to the lower rubber sleeve seat (4123). The outer periphery of the upper cone (4131) and the lower cone (4132) is provided with a protective sleeve (4134). The protective sleeve (4134) is provided with an opening at a position corresponding to the slip (4133). A first return spring (4135) is provided between the protective sleeve (4134) and the slip (4133).

8. The reusable reconnectable packer according to claim 7, characterized in that, The seat locking component (42) includes: The rubber sleeve locking claw (421) is connected to the bushing (4121), and the rubber sleeve locking claw (421) slides in engagement with the inner wall of the upper cone (4131); An annular locking block (422) is disposed on the inner wall of the upper cone (4131); and configured as follows: When the rubber tube (4124) is in a compressed state, the rubber tube locking claw (421) engages with the annular locking block (422) to maintain the compressed state of the rubber tube (4124).

9. The reusable reconnectable packer according to claim 7, characterized in that, The third anchoring component body (413) also includes a locking spring (423), which is disposed between the protective sleeve (4134) and the lower rubber sleeve seat (4123).

10. The reusable drop-and-reconnect packer according to claim 8, characterized in that, The seat locking component (42) further includes a slip ring (424), which is disposed 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 sleeve locking claw (421), so that during the movement of the rubber sleeve locking claw (421) relative to the slip ring (424), the rubber sleeve locking claw (421) can be closed inward to disengage from the annular locking block (422).

11. The reusable drop-and-reconnect packer according to claim 7, characterized in that, The reusable release and reconnection packer also includes a track switching mechanism (5), which includes: The track tube (51) is connected to the end of the center tube (11) away from the upper connecting sleeve (12). The track tube (51) is provided with a plurality of sealing grooves (511) and unsealing grooves (512). The plurality of sealing grooves (511) and unsealing grooves (512) form a J-shaped track. The upper cone (4131), the lower cone (4132) and the slip (4133) are arranged on the outer periphery of the track tube (51). A switching ring (52) is provided with a switching pin (521). The switching ring (52) and the switching pin (521) are disposed within the J-shaped track and configured as follows: When the trajectory 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).

12. The reusable drop-and-reconnect packer according to claim 11, characterized in that, The reusable release and reconnection packer also includes a straightening mechanism (6), which is sleeved on the outer periphery of the track tube (51) and frictionally engages with the inner wall of the sleeve.

13. The reusable drop-and-reconnect packer according to claim 12, characterized in that, The straightening mechanism (6) includes: A straightening base (61) is sleeved on the outer periphery of the track tube (51), and the straightening base (61) is connected to the lower cone (4132); Multiple straightening blocks (62) are spaced apart on the straightening base (61) 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 reusable drop-and-reconnect packer according to claim 13, characterized in that, The reusable release packer also includes a reverse sealing valve mechanism (7), which comprises: A sheath (71) is connected to the end of the track tube (51); The lower connector (72) is connected to the sheath (71); A reverse sealing valve seat (73) is disposed inside the sleeve (71), and the reverse sealing valve seat (73) abuts against the lower connector (72); The valve disc (74) is mounted on the valve seat (73) of the reverse sealing valve by means of a torsion spring (75).

15. The reusable drop-and-reconnect packer according to claim 14, characterized in that, The track tube (51) is provided with a lower connecting sleeve (8) on its outer periphery. The 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 reusable drop-and-reconnect packer according to claim 1, characterized in that, The support cylinder (31) has a second pressurization hole in its wall. The limiting cylinder (33) is configured to move away from the connector (21) under pressurization. A second return spring (34) is provided between the limiting cylinder (33) and the cylinder body (32).

17. A method of operating a reusable packer as described in any one of claims 1 to 16, characterized in that, Includes the following steps: The reusable packer is lowered into the well. During the lowering of the tubing string, the reusable mechanism (3) pushes the sealing locking mechanism (2) to move down, so that the mandrel (23) moves to the sealing locking position, separating the cavity of the central tube (11) from the annulus between the packer and the casing, and maintaining the position of the mandrel (23) through the limiting component (22). Continue lowering the pipe column. When the pipe column is lowered to the preset position, the anchoring component (41) works, so that the anchoring component (41) is supported on the inner wall of the sleeve, and the anchoring component (41) is kept in the state by the seated locking component (42). The limit cylinder (33) moves upward, causing the locking hook on the release and reconnection mechanism (3) to disengage from the control valve seat (311), completing the unlocking of the reconnection locking claw (331). The limit cylinder (33) continues to move upward until the locking hook disengages from the first limit groove (211), the upper tube column, the release and reconnection mechanism (3) and the connector (21) separate, and the release and reconnection packer can be repeatedly used for corresponding operations. After the operation is completed, the release and reconnection mechanism (3) is lowered, so that the reconnection locking claw (331) extends into the connector (21), and the tube column is pressed down. After the reconnection locking claw (331) contacts the inner wall of the connector (21), it retracts, so that the locking hook disengages from the control valve seat (311). The tube column is pressed down further, and the locking hook is locked into the first limit groove (211). Lift the tubing, the limiting component (22) opens, the cavity of the central tube (11) connects with the first hole (121) and the second hole 122, the upper and lower pressures are balanced, continue to lift the tubing, the seat locking component (42) opens, the anchoring component (41) resets, and the reusable release packer is moved to the next working position by moving the tubing.

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