Oil well pressure building unlocking mechanism, oil well setting and unsetting device and packer

Abstract

The invention discloses an oil well pressure building unlocking mechanism, an oil well setting and unsetting device and a packer, and relates to the technical field of oil exploitation equipment.The oil well pressure building unlocking mechanism is provided with a cylinder sleeve, a first locking mechanism and a ball seat unlocking mechanism, multiple stages of shear pin modules which are arranged at intervals are cut off in sequence through axial sliding of the ball seat unlocking mechanism in a sliding space in the cylinder sleeve, and then the oil well setting and unsetting device is started; and then the multi-ring one-way inclined meshing teeth are gradually expanded, so that reliable graded bearing and sequential release in the pressure building process are realized. When the ball is not thrown in place or the pressure fluctuation is small, the multi-stage resistance of the shear pin module can effectively prevent the ball seat from sliding too early and greatly, and unlocking or misoperation in advance is avoided; only when the pressure is continuously accumulated and sequentially overcomes the shearing strength of all the shear pins, opening and unlocking of the meshing teeth are triggered, so that the unlocking time is accurately controlled, and the adaptability to the underground complex pressure environment is improved.

Description

Technical Field

[0001] This invention relates to the field of oil extraction equipment technology, and in particular to an oil well pressure release mechanism, an oil well setting and unsealing device, and a packer. Background Technology

[0002] Packers are commonly used equipment in oil well operations for well washing, stratified water injection, and stratified pumping. In use, packers are usually connected with other functional tubing sections and tubing to form a string that runs from the drilled well to the downhole. After the packer has been set, the corresponding downhole operations are performed.

[0003] In existing technologies, when setting a packer lowered into the wellbore is required, a pressure-holding method is typically used. Specifically, after the packer is in place, a ball is dropped from the tubing string at the wellhead. The ball enters the ball seat at the bottom of the packer for setting, and pressure is applied. During this pressure-holding process, a hydraulic cylinder above the packer drives the packer's rubber sleeve downwards and is extruded, simultaneously causing the jaws on the packer to extend and engage with the inner wall of the casing, completing the setting and sealing operation. When it is necessary to unseal the packer while it is in a set state, the tubing string is usually lifted so that the corresponding structure above the packer can shear the shear pins at the corresponding positions during the lifting process, allowing the rubber sleeve and slips to retract and complete the unsealing operation.

[0004] Although existing technologies can achieve the setting and unsealing functions of packers, they are prone to premature mislocking or premature setting / disconnection when setting and unsealing packers. Affected by downhole pressure fluctuations, minor leaks, or inaccurate ball dropping, the tool cannot maintain a stable pressure state, which affects the success rate of fracturing, setting, and other operations. Summary of the Invention

[0005] The main objective of this invention is to propose an oil well pressure-locking and unlocking mechanism, an oil well setting and unsealing device, and a packer. The aim is to solve the technical problems in the prior art where, when setting and unsealing the packer, premature mislocking or premature setting / disconnection can easily occur. Furthermore, the packer is susceptible to downhole pressure fluctuations, minor leaks, or inaccurate ball placement, which can cause the tool to be unable to maintain a stable pressure-locking state, thus affecting the success rate of fracturing, setting, and other operations.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an oil well pressure relief unlocking mechanism, comprising: A cylinder liner, the top and bottom of which form a first connection position and a second connection position respectively. The first connection position can be connected to an external hydraulic cylinder. A sliding space is formed inside the cylinder liner and extends through it along its length. A shearing module is arranged in the area of ​​the sliding space near the second connection position. The shearing modules are arranged at intervals along the length of the cylinder liner. A first locking mechanism is installed at the second connection position. The first locking mechanism includes a first unlocking component and a first locking component. The first unlocking component has a first through hole aligned with the extending direction of the sliding space. The first locking component has a second through hole communicating with the first through hole and aligned with its extending direction. Multiple rings of interlocking teeth are spaced apart along the length of the first unlocking component's sidewall within the first through hole. All interlocking teeth are inclined towards the direction of the first connection position. A ratchet ring is formed on the outer periphery of the first locking component, corresponding to the interlocking teeth. The inclination direction of the ratchet ring is opposite to that of the interlocking teeth. A ball seat unlocking mechanism is slidably installed in the sliding space and located at one end of the shear pin module near the first connection position. A fluid flow channel is formed through the ball seat unlocking mechanism in the same direction as the extension of the cylinder liner. A ball groove is formed at one end of the ball seat unlocking mechanism facing the first connection position. When the first external ball-seat is sealed in the ball groove and the flow channel is blocked to suppress pressure, the ball seat unlocking mechanism slides along the length of the cylinder liner in the sliding space, sequentially shears the shear pin module, and sequentially opens the biting teeth, so that the first unlocking component unlocks the first locking component.

[0007] The technical solution of this invention, through the setting of a cylinder liner, a first locking mechanism, and a ball seat unlocking mechanism, achieves reliable graded bearing and sequential release during the pressure build-up process by axially sliding the ball seat unlocking mechanism in the sliding space within the cylinder liner, sequentially shearing the multi-stage spaced shearing pin modules, and subsequently gradually opening the multi-ring unidirectional inclined meshing teeth. When the ball is not in place or the pressure fluctuation is small, the multi-stage resistance of the shearing pin module can effectively prevent the ball seat from sliding too much prematurely, avoiding premature unlocking or malfunction. Only when the pressure continues to accumulate and successively overcomes the shearing strength of all shearing pins is the meshing teeth triggered to open and unlock, thereby precisely controlling the unlocking timing and improving adaptability to complex downhole pressure environments. At the same time, the cooperation between the multi-ring meshing teeth and the oppositely inclined ratchet ring provides a strong unidirectional locking bearing capacity before unlocking, while the gradual opening of the ball seat during unlocking achieves smooth disengagement, avoiding residual biting force or sudden jamming, ensuring a smooth and reliable unlocking process, without incomplete unlocking or jamming, thereby significantly improving the success rate of unsealing operations after downhole setting and the overall reliability of the tool. Attached Figure Description

[0008] 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, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of the structure of the oil well pressure relief unlocking mechanism provided by the present invention; Figure 2 for Figure 1 The diagram shows the internal structure of the oil well pressure relief unlocking mechanism in the example. Figure 3 for Figure 1 A schematic diagram of the structure of an oil well pressure relief unlocking mechanism in the explosive state, as shown in the example. Figure 4 for Figure 2 The internal structure diagram of the cylinder liner is shown in the example. Figure 5 for Figure 2 A schematic diagram of the structure of the first locking component in the example; Figure 6 for Figure 2 A schematic diagram of the ball seat unlocking mechanism shown in the example; Figure 7 This is a schematic diagram of the structure of the oil well sealing and unsealing device as an example of the present invention; Figure 8 for Figure 7 A schematic diagram of the internal structure of the device shown in the example; Figure 9 for Figure 8 A schematic diagram of the device shown in the example; Figure 10 for Figure 9 A schematic diagram of the anchoring mechanism in the example; Figure 11 for Figure 9 A schematic diagram of the anchoring component in the example; Figure 12 for Figure 11 The diagram shows the structure of the pressure transmission sleeve in the example.

[0010] Explanation of icon numbers: 100. Cylinder liner; 110. First connection position; 120. Second connection position; 130. Sliding space; 200. Shear pin module; 300. First locking mechanism; 310. First unlocking component; 320. First locking component; 311. First through hole; 321. Second through hole; 312. Engaging teeth; 322. Racket ring; 400. Ball seat unlocking mechanism; 410. Fluid flow channel; 420. Ball groove; 323. Sleeve body; 324. First pawl; 430. Seat body; 440. Unlocking rod; 450, clearance passage; 500, downhole casing; 600, oil well pressure release mechanism; 700, hydraulic cylinder body; 710, central tube; 720, abutment seat; 730, pressure release ball seat; 800, anchoring mechanism; 810, connecting seat; 820, elastic reset component; 830, pressure transmission sleeve; 840, setting and anchoring assembly; 831, extrusion deformation zone; 832, engagement zone; 833, rubber sleeve; 834, anchoring block; 10, first external ball launcher; 20, second external ball launcher.

[0011] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0013] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0014] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0015] Existing technologies can achieve the setting and unsealing functions of packers. However, when setting and unsealing packers, existing technologies are prone to premature mislocking or premature setting / disconnection. Affected by downhole pressure fluctuations, minor leaks, or inaccurate ball dropping, the tool cannot maintain a stable pressure state, which affects the success rate of fracturing, setting, and other operations.

[0016] This invention proposes an oil well pressure release mechanism, an oil well setting and unsealing device, and a packer.

[0017] Please see Figures 1 to 12 For ease of understanding, this oil well pressure relief unlocking mechanism includes: The cylinder liner 100 has a first connection position 110 and a second connection position 120 formed at its top and bottom, respectively. The first connection position 110 can be connected to an external hydraulic cylinder. A sliding space 130 is formed inside the cylinder liner 100 and extends through it along its length. A shearing module 200 is arranged in the area of ​​the sliding space 130 near the second connection position 120. The shearing modules 200 are arranged at intervals along the length of the cylinder liner 100. A first locking mechanism 300 is installed at a second connection position 120. The first locking mechanism 300 includes a first unlocking component 310 and a first locking component 320. The first unlocking component 310 has a first through hole 311 extending in the same direction as the sliding space 130. The first locking component 320 has a second through hole 321 communicating with the first through hole 311 and extending in the same direction. Multiple rings of interlocking teeth 312 are spaced apart along the length of the sidewall of the first unlocking component 310 within the first through hole 311. All interlocking teeth 312 are inclined towards the first connection position 110. A ratchet ring 322, corresponding to the interlocking teeth 312, is formed on the outer periphery of the first locking component 320. The inclination direction of the ratchet ring 322 is opposite to that of the interlocking teeth 312. The ball seat unlocking mechanism 400 is slidably installed in the sliding space 130 and located at one end of the shear pin module 200 near the first connection position 110. A fluid flow channel 410 is formed through the ball seat unlocking mechanism 400 in the same direction as the extension of the cylinder liner 100. A ball groove 420 is formed at one end of the ball seat unlocking mechanism 400 facing the first connection position 110. When the first external ball 10 is seated in the ball groove 420 and the liquid flow channel 410 is sealed to block pressure, the ball seat unlocking mechanism 400 slides along the length of the cylinder liner 100 in the sliding space 130, sequentially cutting the shear pin module 200 and sequentially opening the biting teeth 312, so that the first unlocking component 310 and the first locking component 320 are unlocked.

[0018] Specifically, the cylinder liner 100, as the core carrier of the well pressure relief and unlocking mechanism 600, has a first connection position 110 at its top and a second connection position 120 at its bottom. The first connection position 110 is reliably connected to an external hydraulic cylinder to receive hydraulic power pumped from the wellhead. A sliding space 130 is formed inside the cylinder liner 100 along its axial direction (length direction). A shearing module 200 is provided in the area near the second connection position 120 of the sliding space 130. The shearing module 200 is composed of multiple shearing pins arranged at intervals along the axial direction of the cylinder liner 100. Each shearing pin passes laterally through the wall of the sliding space 130 and is fixed in the corresponding position to provide graded resistance.

[0019] The first locking mechanism 300 is installed and fixed at the second connection position 120 of the cylinder liner 100, and is composed of a first unlocking component 310 and a first locking component 320. The first unlocking component 310 has an axially extending first through hole 311, which extends in the same direction as the sliding space 130 of the cylinder liner 100. The first locking component 320 has a second through hole 321, which communicates with and is axially aligned with the first through hole 311, thus forming a continuous central channel. The first unlocking component 310 has multiple rings of meshing teeth 312 on the inner wall of the first through hole 311. These meshing teeth 312 are spaced apart axially, and the tooth surfaces of each meshing tooth 312 are inclined towards the first connection position 110 (i.e., the top of the cylinder liner 100), forming a unidirectional inclined structure. A ratchet ring 322 is formed on the outer peripheral surface of the first locking component 320. The tooth shape of the ratchet ring 322 corresponds to and matches the meshing tooth 312, but the tilt direction of the ratchet ring 322 is opposite to that of the meshing tooth 312. That is, the tooth surface of the ratchet ring 322 faces the opposite direction, so that the two mesh and lock each other in the normal state, preventing the first locking component 320 from moving axially relative to the first unlocking component 310.

[0020] The ball seat unlocking mechanism 400 is slidably installed within the sliding space 130 of the cylinder liner 100 and located at the end of the scissor bolt module 200 near the first connection position 110, i.e., above the scissor bolt module 200 (near the hydraulic input end). An axial flow channel 410 is formed inside the ball seat unlocking mechanism 400, which extends in the same direction as the cylinder liner 100, ensuring free flow of liquid when no ball is being thrown. A ball groove 420 is formed at the end of the ball seat unlocking mechanism 400 facing the first connection position 110 (i.e., the upper end) for receiving externally thrown balls.

[0021] During the pressure release operation, the first external ball 10 is dropped from the wellhead. The first external ball 10 is seated in the ball groove 420 of the ball seat unlocking mechanism 400, sealing and blocking the fluid flow channel 410. At this time, hydraulic pressure continues to be applied to the cylinder liner 100 through the first connection position 110. The pressure acts on the upper end face of the ball seat unlocking mechanism 400, pushing the ball seat unlocking mechanism 400 downward along the sliding space 130 (towards the second connection position 120). During the sliding process, the ball seat unlocking mechanism 400 first contacts and sequentially cuts each shear pin in the shear pin module 200. Each shear pin cut overcomes a first-level preset resistance, realizing a graded load-bearing and gradual energy release process, avoiding a single high-pressure impact that could cause the mechanism to lose control or be damaged. As the ball seat unlocking mechanism 400 continues to descend, its outer peripheral structure contacts and acts on the inner side of the engagement teeth 312 of the first unlocking component 310. Since the engagement teeth 312 are inclined upwards, the ball seat unlocking mechanism 400 generates a radially outward spreading force as it descends. This force gradually elastically spreads the multi-ring engagement teeth 312 outwards, causing the engagement teeth 312 to disengage from the ratchet ring 322 of the first locking component 320. As all the engagement teeth 312 are sequentially spread open, the first unlocking component 310 and the first locking component 320 are completely unlocked. The first locking component 320 can then undergo axial displacement relative to the cylinder liner 100, thereby releasing the subsequently connected components (such as the rubber sleeve 833 compression mechanism or the slip anchoring mechanism 800), completing the overall tool unlocking action.

[0022] In this embodiment, reliable graded bearing and sequential release during the pressure buildup process are achieved through the axial sliding of the ball seat unlocking mechanism 400 in the sliding space 130 within the cylinder liner 100, the sequential shearing of the multi-level spaced shearing pin modules 200, and the subsequent gradual opening of the multi-ring unidirectional inclined engagement teeth 312. When the ball is not in place or the pressure fluctuation is small, the multi-level resistance of the shearing pin module 200 can effectively prevent the ball seat from sliding too much prematurely, avoiding premature unlocking or malfunction. Only when the pressure continues to accumulate and successively overcomes the shearing strength of all the shearing pins is the engagement teeth 312 triggered to open and unlock, thereby precisely controlling the unlocking timing and improving adaptability to complex downhole pressure environments. Meanwhile, the multi-ring biting teeth 312 and the oppositely inclined ratchet ring 322 provide strong unidirectional locking load capacity before unlocking, while the ball seat gradually opens during unlocking to achieve smooth disengagement, avoiding residual biting force or sudden jamming, ensuring a smooth and reliable unlocking process, without incomplete unlocking or jamming, thereby significantly improving the success rate of unsealing operations after downhole setting and the overall reliability of the tool.

[0023] More specifically, the shear pin module 200 can employ multiple layers of shear pins with different shear strengths spaced axially. Each layer of shear pins has a different shear strength; for example, the shear strength of the shear pins from the first connection position 110 towards the second connection position 120 can be sequentially set to 15MPa, 18MPa, 20MPa, 22MPa, and 25MPa, forming an increasing resistance distribution and further optimizing the graded release process. In another embodiment, the engagement teeth 312 can be configured as three to five rings. The number of teeth and axial spacing of each ring of engagement teeth 312 are adjusted according to the locking force requirements. For example, each ring can have 8-12 teeth with a tooth height of 0.8-1.5mm, ensuring uniform radial deformation and preventing plastic damage during the opening process.

[0024] In one embodiment, the first locking component 320 includes a sleeve body 323, a second through hole 321 is formed in the sleeve body 323, and a multi-ring ratchet ring 322 is interference-fitted on the outer wall of the sleeve body 323. All the ratchet rings 322 are distributed at equal intervals along the length direction of the sleeve body 323, and the diameter of all the ratchet rings 322 decreases sequentially in the direction away from the first unlocking component 310.

[0025] Specifically, a second through hole 321 is formed axially through the interior of the sleeve body 323. The second through hole 321 is coaxially connected with the first through hole 311 on the first unlocking component 310 and maintains the same extension direction, thereby ensuring that the fluid channel remains unobstructed before and after unlocking. A multi-ring ratchet ring 322 is installed on the outer wall of the sleeve body 323 by an interference fit. All ratchet rings 322 are evenly spaced along the axial direction (length direction) of the sleeve body 323, and the outer diameter of each ratchet ring 322 decreases sequentially in the direction away from the first unlocking component 310. That is, the ratchet ring 322 closer to the first unlocking component 310 has a larger diameter, and the ratchet ring 322 further away from the first unlocking component 310 has a smaller diameter, forming an axially tapering ratchet layout.

[0026] During assembly, the inner wall of the first through hole 311 of the first unlocking component 310 has been pre-machined to form multiple rings of engagement teeth 312 inclined towards the first connection position 110. The multi-ring ratchet ring 322 carried by the sleeve body 323 is pushed into the first through hole 311 from the side of the second connection position 120. Since the ratchet ring 322 and the engagement teeth 312 are inclined in opposite directions and have a unidirectional meshing characteristic, the sleeve body 323 can slide into the sleeve body 323 relative to the inclined surface of the engagement teeth 312 during installation until it reaches the predetermined axial position. At this time, the multi-ring ratchet ring 322 achieves full circumferential engagement and locking with the engagement teeth 312 at the corresponding positions. The interference fit ensures that there is no relative rotation or axial movement between the ratchet ring 322 and the outer wall of the sleeve body 323. Under normal working conditions, the ratchet ring 322 and the meshing teeth 312 jointly bear the axial load, which firmly locks the first locking component 320 (sleeve body 323) and the first unlocking component 310, preventing accidental relative displacement during pressure setting or normal production.

[0027] When the pressure-locking phase begins, the ball seat unlocking mechanism 400 moves downward along the sliding space 130 under hydraulic pressure. During the process of cutting off the topmost pin and moving to the layer of pins adjacent to the cut pins, the ball seat unlocking mechanism 400 approaches the engagement teeth 312 and the ratchet ring 322, causing the engagement teeth 312 and the ratchet ring 322 to unlock for the first time. In this state, a movement gap is provided for the external structure connected to the ratchet ring 322. After sequentially cutting off the pin modules 200, their outer circumferential surfaces contact and act on the inner side of the engagement teeth 312 of the first unlocking component 310. The engagement teeth 312 gradually open elastically under radial outward support force, and the multi-ring engagement teeth 312 sequentially disengage from the corresponding ratchet rings 322 from top to bottom (i.e., from the end near the first connection position 110 towards the second connection position 120). Because the outer diameter of the ratchet ring 322 decreases axially downwards, meaning the lower ratchet ring 322 has a smaller diameter, the radial deformation required for its corresponding biting teeth 312 to open is correspondingly reduced. Therefore, the opening resistance of the biting teeth 312 during the unlocking process exhibits a gradual characteristic from large to small. This release sequence with decreasing resistance makes the entire unlocking action smoother, avoiding the sudden disengagement or excessive residual local biting resistance that may occur in the later stages of unlocking in traditional equal-diameter ratchet structures.

[0028] In this embodiment, during the initial unlocking stage, the upper, larger-diameter ratchet ring 322 maintains strong engagement with the meshing teeth 312, providing sufficient residual locking capability to prevent minor displacement caused by pressure fluctuations. In the later stages of unlocking, the lower, smaller-diameter ratchet rings 322 disengage successively, further reducing residual resistance until all ratchet rings 322 disengage from the meshing teeth 312, achieving complete and unobstructed unlocking. This tapered diameter layout, combined with the equidistant distribution of multiple rings, effectively solves the problems of uneven resistance distribution and potential jamming or incomplete unlocking in traditional ratchet locking mechanisms during unlocking. It significantly improves the stability and reliability of the unlocking process under high-pressure conditions, while also reducing the total radial opening force that the ball seat unlocking mechanism 400 needs to overcome, reducing the impact load on the inner wall of the cylinder liner 100 and surrounding components, further enhancing the overall durability and operational success rate of the mechanism.

[0029] In one embodiment, the ratchet ring 322 can have three to six rings, such as a five-ring structure, with the outer diameter of each ring decreasing by 0.4 mm to 0.8 mm from top to bottom (depending on the inner diameter of the cylinder liner 100). The number of teeth per ring is controlled to be 10 to 16, and the tooth height is 0.6 mm to 1.2 mm to balance the locking force and unlocking resistance. In another embodiment, the ratchet ring 322 has three rings with a larger decreasing range (the difference in outer diameter of each ring is about 1.0 mm to 1.5 mm), which is suitable for deep well high-temperature working conditions with higher requirements for unlocking force gradient.

[0030] In one embodiment, the first unlocking component 310 includes a plurality of first pawls 324, all of which are circumferentially spaced at the second connection position 120, and all of which extend along the length of the cylinder liner 100 in a direction away from the second connection position 120. The end of the first pawl 324 away from the second connection position 120 is formed with a meshing tooth 312 that is the same number as the ratchet ring 322 and corresponds to it in a one-to-one meshing engagement. When the first external ball 10 is seated in the ball groove 420 and the flow channel 410 is sealed to suppress pressure, and the ball seat unlocking mechanism 400 sequentially cuts the shear pin module 200, all the first pawls 324 are opened to unlock sequentially with the ratchet ring 322.

[0031] Specifically, the first unlocking component 310 includes multiple first pawls 324. All first pawls 324 are evenly spaced around the periphery of the second connection position 120, and each first pawl 324 extends away from the second connection position 120 along the axial direction (length direction) of the cylinder liner 100, i.e., towards the first connection position 110, forming a cantilever structure. The end of the first pawl 324 away from the second connection position 120 (i.e., the free end) is provided with a biting tooth 312. The number of biting teeth 312 corresponds one-to-one with the number of ratchet rings 322 on the first locking component 320 and their positions are aligned. Each free end of the first pawl 324 is provided with a corresponding ring of biting teeth 312, thereby achieving a step-by-step meshing engagement between the multi-ring biting teeth 312 and the multi-ring ratchet ring 322 in the assembled state.

[0032] During assembly, multiple first pawls 324 of the first unlocking component 310 are pushed into the sliding space 130 from the second connection position 120 side of the cylinder liner 100. The cantilever portion of the first pawl 324 extends axially and enters the area of ​​the first through hole 311. The meshing teeth 312 on its free end engage circumferentially with the ratchet ring 322 on the outer wall of the sleeve body 323. During normal setting and bearing or production, the meshing teeth 312 of the first pawl 324 can effectively prevent the sleeve body 323 (first locking component 320) from moving axially upward (towards the first connection position 110), providing reliable axial locking; in the unlocking direction (downward), the pawl is allowed to slide out relatively after being radially opened.

[0033] During the pressure-locking operation, the first external ball 10 is seated in the ball groove 420 of the ball seat unlocking mechanism 400 and seals the fluid flow channel 410. After the hydraulic pressure is applied, the ball seat unlocking mechanism 400 moves downward along the sliding space 130, cutting off each of the shear pins in the shear pin module 200 in sequence, overcoming multiple levels of resistance. When the ball seat unlocking mechanism 400 continues to descend to near the second connection position 120, its outer circumferential surface contacts the inner surface (cantilever inner wall) of multiple first pawls 324 and generates a radially outward spreading force. Since the first pawls 324 adopt a cantilevered circumferentially spaced distribution structure, this radial spreading force causes the free ends of each first pawl 324 to elastically deform outward synchronously, driving each ring engagement tooth 312 to simultaneously disengage from the corresponding ratchet ring 322. As the ball seat unlocking mechanism 400 continues to descend, the deformation of the first pawl 324 gradually increases, and all the biting teeth 312 sequentially disengage from the ratchet ring 322 from top to bottom (from the end near the first connection position 110 towards the second connection position 120), ultimately achieving complete unlocking of the first unlocking component 310 and the first locking component 320.

[0034] In this embodiment, by replacing the traditional integrated bite tooth 312 structure with multiple circumferentially spaced first pawls 324, and having each pawl's free end bear a ring of bite teeth 312, this structure allows each pawl to undergo independent radial elastic deformation during the unlocking process. This avoids local stress concentration or uneven deformation caused by excessive rigidity when the integrated structure is opened. Simultaneously, the cantilevered extension of the first pawls 324 provides good flexibility and a controllable deformation range. Under the gradual pushing of the ball seat unlocking mechanism 400, the disengagement process between the bite teeth 312 and the ratchet ring 322 exhibits a step-by-step and orderly characteristic, significantly reducing the risk of sudden disengagement or excessive residual local bite resistance. This effectively solves the problems of jamming, incomplete unlocking, or sudden resistance changes in the later stages of unlocking that are common in traditional unlocking mechanisms under high pressure conditions, thereby improving the stability, reliability, and adaptability to complex downhole conditions during the pressure-locking unlocking process.

[0035] In one embodiment, the number of first pawls 324 can be set to 8 to 12, evenly distributed circumferentially. The axial extension length of each pawl is 80 mm to 150 mm (adjusted according to the overall size of the cylinder liner 100). The tooth height of the free end meshing teeth 312 is controlled between 0.7 mm and 1.4 mm, and the tooth surface inclination angle is 45° to 60° to ensure sufficient meshing strength and moderate opening resistance. In another embodiment, the number of first pawls 324 is reduced to 6, the circumferential spacing of the pawls is increased accordingly, and the radial thickness of each pawl is slightly increased (e.g., from 3 mm to 4.5 mm), which is suitable for ultra-deep wells or high-temperature conditions where the instantaneous impact load of unlocking is more demanding.

[0036] In one embodiment, the shearing pin module 200 includes shearing pin rings in the same number as the ratchet rings 322. All shearing pin rings are spaced apart along the length of the cylinder liner 100. The spacing between any two adjacent shearing pin rings is the same as the spacing between any two adjacent ratchet rings 322. Each shearing pin ring has multiple shearing pins spaced apart circumferentially along the sliding space 130. The ball seat unlocking mechanism 400 includes: A seat body 430 is slidably mounted within a sliding space 130. The seat body 430 is recessed on the side facing the first connection position 110 towards the second connection position 120 to form a ball groove 420; and... Multiple unlocking levers 440 are distributed circumferentially at intervals at one end of the seat body 430 facing the second connection position 120. The unlocking levers 440 form a clearance channel 450 that is consistent with the number of shear pins and corresponds one-to-one. All unlocking levers 440 are integrally formed with the seat body 430. The extension direction of the unlocking levers 440 is consistent with the extension direction of the sliding space 130, and the unlocking levers 440 can slide with the seat body 430 within the sliding space 130.

[0037] Specifically, each shear pin ring is composed of multiple shear pin components, which are evenly spaced along the circumference of the sliding space 130. Each shear pin component passes laterally through the wall of the cylinder liner 100 and extends into the sliding space 130, forming a graded obstruction to the downward movement of the ball seat unlocking mechanism 400.

[0038] The ball seat unlocking mechanism 400 includes a seat body 430 and multiple unlocking rods 440. The seat body 430 is slidably installed in the sliding space 130 of the cylinder liner 100. A ball groove 420 is recessed on the side facing the first connection position 110 (i.e., the upper side) and towards the second connection position 120, for receiving the first external ball 10 and sealing off the fluid passage 410. Multiple unlocking rods 440 are circumferentially spaced at one end (i.e., the lower end) of the seat body 430 facing the second connection position 120. A clearance channel 450 is formed between each unlocking rod 440, matching the number and position of the shear pins. All unlocking rods 440 are integrally formed with the seat body 430. The axial extension direction of the unlocking rods 440 is completely consistent with the extension direction of the sliding space 130, allowing the unlocking rods 440 to slide axially within the sliding space 130 along with the seat body 430.

[0039] In this embodiment, by matching the number and spacing of the shearing rings with the number and spacing of the ratchet rings 322, and by using multiple circumferentially distributed unlocking rods 440 in conjunction with the shearing components, the precise graded release of multi-stage shear resistance and the sequential linkage of unlocking actions during the pressure build-up process are achieved. This effectively suppresses premature mislocking caused by pressure fluctuations or premature failure of single-stage shearing rings. At the same time, it ensures that the unlocking action can be completed smoothly, continuously, and without jamming after the predetermined pressure accumulation is reached. This significantly improves the precise controllability of the unlocking timing and the smooth reliability of the unlocking process in high-pressure pressure build-up operations, reduces the risk of tool jamming or incomplete unlocking due to asynchronous actions, and thus improves the overall success rate of downhole operations and the tool's service life.

[0040] More specifically, both the shearing ring and the ratchet ring 322 are configured as five rings, with 12 shearing pins per ring, evenly distributed circumferentially. The shearing strength of the shearing pins increases from top to bottom (e.g., 15 MPa for the first ring, 18 MPa for the second ring, 20 MPa for the third ring, 22 MPa for the fourth ring, and 25 MPa for the fifth ring). The spacing between adjacent shearing rings is 18 mm, perfectly matching the spacing of the ratchet ring 322. In another embodiment, both the shearing ring and the ratchet ring 322 are four rings, with 10 shearing pins per ring and the spacing adjusted to 22 mm. The shearing strength distribution is more gradual (linearly increasing from 16 MPa to 24 MPa), suitable for high-temperature deep well conditions where the requirements for the gradient change of unlocking force are relatively gentle.

[0041] Based on the same technical concept, in a second aspect, the present invention also proposes an oil well setting and unsetting device, which is installed inside an external downhole casing 500. The oil well setting and unsetting device includes: The first aspect is the oil well pressure relief unlocking mechanism 600; Hydraulic cylinder body 700 is installed at one end of cylinder liner 100 of oil well pressure relief unlocking mechanism 600; A central tube 710 is slidably fitted with a cylinder liner 100 on its outer periphery. A third connection position is formed at the end of the central tube 710 furthest from the well pressure-locking unlocking mechanism 600. This third connection position can be connected to an external tubing string. An abutment seat 720 is interference-fitted onto the outer periphery of the central tube 710 near the third connection position. A pressure-locking ball seat 730 is disposed within the cavity of the central tube 710 near the third connection position. Anchoring mechanism 800 is sleeved on the outer periphery of central tube 710 and located between pressure unlocking mechanism and abutment seat 720. One end of anchoring mechanism 800 is connected to the end of cylinder liner 100 away from hydraulic cylinder body 700, and the other end abuts against abutment seat 720. Anchoring mechanism 800 has a compressed and folded anchoring state and an extended and reset unlocking state. When the second external ball 20 is seated on the pressure-blocking ball seat 730 to block pressure, the hydraulic cylinder 700 drives the oil well pressure-blocking unlocking mechanism 600 to move toward the third connection position, so that the anchoring mechanism 800 switches to the anchoring state and anchors to the pipe wall of the downhole casing 500. When the first external ball 10 is seated in the ball groove 420 and the liquid flow channel 410 is sealed to prevent pressure buildup, the ball seat unlocking mechanism 400 unlocks the first unlocking component 310 and the first locking component 320, so that the anchoring mechanism 800 switches from the anchoring state to the unlocking state and is unsealed.

[0042] Specifically, the end of the central tube 710 furthest from the well pressure release mechanism 600 forms a third connection position, which is connected to the external tubing string by thread or snap-fit. An abutment seat 720 is interference-fitted onto the outer periphery of the central tube 710 near the third connection position. The abutment seat 720 has an annular boss structure for axial limiting and force transmission. A pressure-reducing ball seat 730 is installed inside the cavity of the central tube 710 near the third connection position to receive the second external ball 20 for setting and pressure-reducing. The anchoring mechanism 800 is coaxially sleeved on the outer periphery of the central tube 710 and located between the well pressure release mechanism 600 and the abutment seat 720. Its two ends are fixedly connected to the end of the cylinder liner 100 furthest from the hydraulic cylinder body 700 (i.e., the side of the second connection position 120) and abut against the upper end face of the abutment seat 720. When the anchoring mechanism 800 is axially compressed, it is in a folded and contracted anchoring state, at which time the slip teeth extend outward and bite into the inner wall of the downhole casing 500; when it is axially stretched and reset, it is in an extended state, and the slip teeth retract radially and disengage from the inner wall of the casing, thereby unlocking.

[0043] The setting and unsealing operation is as follows: After the entire well setting and unsealing device is lowered to the predetermined depth downhole along with the tubing string, the second external ball 20 is dropped from the wellhead. The second external ball 20 descends along the inner cavity of the central tube 710 and sets on the pressure-blocking ball seat 730 near the third connection position of the central tube 710, sealing and isolating the lower flow channel of the central tube 710. At this time, hydraulic fluid continues to be pumped from the top of the tubing string. The pressure is applied to the first connection position 110 of the cylinder liner 100 through the hydraulic cylinder body 700, pushing the cylinder liner 100 and the well pressure-blocking and unlocking mechanism 600 to move axially towards the third connection position (i.e., towards the abutment seat 720). The cylinder liner 100 moves and compresses the anchoring mechanism 800, gradually changing it from an initial relaxed and extended state to a compressed and folded state. The slip teeth inside the anchoring mechanism 800 are opened radially outward under the action of compression force and bite the inner wall of the downhole casing 500. At the same time, the rubber sleeve 833 is squeezed and expanded to stick to the casing, realizing reliable anchoring and annular sealing of the device.

[0044] The unsealing process is as follows: After completing the corresponding downhole operations, when it is necessary to unseal the device, the first external ball 10 is dropped from the wellhead. The ball descends along the annular channel between the central tube 710 and the cylinder liner 100 and is seated in the ball groove 420 of the ball seat unlocking mechanism 400 in the oil well pressure release mechanism 600, sealing and isolating its internal fluid flow channel 410. At this time, hydraulic pressure is continued to be applied, and the pressure acts on the upper end face of the ball seat unlocking mechanism 400, pushing it to move downward along the sliding space 130 of the cylinder liner 100, sequentially shearing each shearing ring in the shearing pin module 200, overcoming multiple levels of resistance. Subsequently, the ball seat unlocking mechanism 400 continues to descend, and the outer circumferential surface of its unlocking rod 440 acts on the inner side of the multiple first pawls 324 of the first unlocking component 310, causing each first pawl 324 to elastically open outward, driving each ring engagement tooth 312 to sequentially disengage from the corresponding ratchet ring 322 on the first locking component 320 (sleeve body 323). As the first unlocking component 310 and the first locking component 320 are completely unlocked, the first locking component 320 can undergo axial relative displacement relative to the cylinder liner 100. When the tubing is lifted or hydraulically released, the compressive force on the anchoring mechanism 800 is released, the slip teeth and rubber sleeve 833 gradually retract radially, and the anchoring mechanism 800 returns from the compressed and folded anchoring state to the extended and reset unlocking state. The device disengages from the inner wall of the downhole casing 500, achieving safe unsealing.

[0045] In this embodiment, by organically integrating the well pressure release mechanism 600 with the hydraulic cylinder 700, central tube 710, and anchoring mechanism 800, and utilizing the independent triggering paths of the second external ball 20 controlling the setting and pressure release, and the first external ball 10 controlling the unlocking and pressure release, this implementation effectively avoids the premature setting, premature unlocking, or loss of control that occurs with traditional tools under conditions of pressure fluctuations, minor leaks, or incomplete ball placement. During setting, the hydraulic cylinder 700 directly drives the cylinder liner 100 to compress the anchoring mechanism 800, achieving reliable anchoring and sealing. During unlocking, the multi-stage shear pin graded bearing of the pressure release mechanism and the progressive unlocking of the pawl-ratchet ring 322 ensure that unlocking is triggered only after sufficient pressure accumulation and sequential overcoming of all preset resistances, avoiding malfunctions caused by unstable downhole pressure. The precise matching of the above structure and action sequence significantly improves the stability and controllability of the setting and unlocking processes, reduces the risk of tool loss of control during operations, and thus improves the overall success rate and operational safety of downhole operations such as fracturing and stratified water injection.

[0046] More specifically, the anchoring mechanism 800 adopts a bidirectional slip + composite rubber sleeve structure. The slip teeth are divided into upper and lower groups, and the rubber sleeve 833 is located between the two groups of slips. The compression stroke is 80mm to 120mm, suitable for conventional fracturing operations in medium-deep wells. In another embodiment, the anchoring mechanism 800 adopts a unidirectional slip + multi-stage stacked rubber sleeve form. The slip teeth are only set in one group and located below the rubber sleeve 833. The compression stroke is increased to 150mm to 200mm, suitable for ultra-deep wells or scenarios requiring greater anchoring force under high temperature and high pressure conditions.

[0047] In one embodiment, the anchoring mechanism 800 includes: Connecting seat 810 is slidably sleeved on the outer periphery of central tube 710. Connecting seat 810 is connected to first locking member 320. One end of connecting seat 810 away from first locking member 320 is formed with an installation position. The elastic reset member 820 has one end connected to the installation position and extends along the length of the central tube 710 toward the abutment seat 720. A pressure transmission sleeve 830 is sleeved on the outer periphery of the central tube 710. One end of the pressure transmission sleeve 830 is connected to the connecting seat 810, and the other end is slidably engaged with the abutment seat 720; and, A setting and anchoring assembly 840 is installed on the outer periphery of the pressure transmission sleeve 830 and is located close to the abutment seat 720. An elastic reset member 820 extends to connect with the setting and anchoring assembly 840. When the second external ball 20 is seated on the pressure-blocking ball seat 730 to block pressure, the hydraulic cylinder 700 drives the oil well pressure-blocking unlocking mechanism 600 to move the connecting seat 810 toward the third connecting position, causing the pressure transmission sleeve 830 to retract. When the pressure transmission sleeve 830 abuts against the wall of the downhole casing 500, the setting and anchoring assembly 840 extends and anchors to the wall of the downhole casing 500. When the first external ball 10 is seated in the ball groove 420 and the liquid flow channel 410 is sealed to block pressure, the ball seat unlocking mechanism 400 unlocks the first unlocking component 310 from the first locking component 320, and the elastic reset component 820 drives the seat anchoring assembly 840 to retract and unseal.

[0048] Specifically, the connecting seat 810 is slidably sleeved on the outer periphery of the central tube 710. Its end near the well pressure release mechanism 600 is reliably axially fixedly connected to the first locking component 320 (sleeve body 323). The end of the connecting seat 810 away from the first locking component 320 forms an annular mounting position for fixing one end of the elastic reset member 820. The elastic reset member 820 extends axially (lengthwise) towards the abutment seat 720 along the central tube 710, and its other end is connected to the setting and anchoring assembly 840. The pressure transmission sleeve 830 is coaxially sleeved on the outer periphery of the central tube 710. One end is fixedly connected to the connecting seat 810, and the other end forms a sliding fit with the abutment seat 720, meaning that during the setting process, the pressure transmission sleeve 830 can axially compress and slide relative to the abutment seat 720. The setting and anchoring assembly 840 is mounted on the outer periphery of the pressure transmission sleeve 830 and located near the abutment seat 720. It contains radially retractable anchoring teeth (slips) and radially compressible sealing sleeves. The resilient reset member 820 extends to the setting and anchoring assembly 840 and is connected to its internal moving parts.

[0049] During the setting operation, after the second external ball 20 sets in the pressure-retaining ball seat 730 inside the central tube 710 and seals the lower flow channel, the pumped hydraulic fluid acts on the cylinder liner 100 through the hydraulic cylinder body 700, pushing the cylinder liner 100 and the oil well pressure-retaining unlocking mechanism 600 to move towards the third connection position (i.e., towards the abutment seat 720). The first locking component 320 then drives the connecting seat 810 to move axially in the same direction. The connecting seat 810 compresses the elastic reset component 820 and pushes the pressure transmission sleeve 830 to contract towards the abutment seat 720. The lower end face of the pressure transmission sleeve 830 gradually approaches and finally abuts against the upper end face of the abutment seat 720, forming an axial force transmission path. As hydraulic pressure continues to be applied, the pressure is transmitted through the pressure transmission sleeve 830 to the setting and anchoring assembly 840. Under axial compressive force, the internal anchoring teeth of the setting and anchoring assembly 840 extend radially outward along the guide ramp and engage with the inner wall of the downhole casing 500. Simultaneously, the sealing sleeve is compressed and expands radially to adhere tightly to the inner wall of the casing, achieving reliable anchoring and annular sealing of the device. During this process, the elastic reset element 820 is continuously compressed and stores sufficient elastic potential energy.

[0050] During the unsealing process, after the first external ball 10 is seated in the ball groove 420 of the ball seat unlocking mechanism 400 and the fluid channel 410 is sealed, hydraulic pressure is continued to be applied. The ball seat unlocking mechanism 400 descends along the sliding space 130, sequentially cutting the shear pin module 200 and opening multiple first pawls 324, so that the first unlocking component 310 and the first locking component 320 are completely unlocked. At this time, the first locking component 320 (and the connecting seat 810 fixed thereto) gains axial freedom relative to the cylinder liner 100. After the tubing is lifted or the hydraulic pressure is released, the connecting seat 810, under the action of the elastic reset component 820 releasing the stored potential energy, drives the pressure transmission sleeve 830 to move in a direction away from the abutment seat 720 (i.e., towards the first connection position 110). The axial compression between the pressure transmission sleeve 830 and the abutment seat 720 is released, the setting and anchoring assembly 840 loses the continuous axial compression force, and its internal anchoring teeth retract radially under the action of the self-resetting spring or structural guidance. The sealing rubber sleeve simultaneously and elastically retracts and detaches from the inner wall of the sleeve, thereby restoring the anchoring mechanism 800 from the compressed anchoring state to the relaxed unlocking state, achieving safe and complete unsealing.

[0051] In this embodiment, by directly connecting the connecting seat 810 to the first locking component 320, using the pressure transmission sleeve 830 as the compression force transmission path, and employing the elastic reset component 820 throughout to provide reset driving force, and by positioning the setting and anchoring component 840 close to the abutment seat 720, this embodiment achieves mechanical decoupling and reliable linkage between setting and unsetting actions. During setting, the hydraulic drive path is clear and the force transmission is direct, avoiding force attenuation or action lag caused by too many intermediate links in traditional structures. During unsetting, the elastic reset component 820 releases its stored energy at once to drive the anchoring component to retract synchronously, eliminating the defect of traditional tools that still require additional lifting force or multiple pressurizations to completely unseal after unlocking. This effectively solves problems such as incomplete unsetting under high pressure conditions, residual jamming of slips, or adhesion of the rubber sleeve 833 to the inner wall of the casing, significantly improving the success rate of device unsetting, reducing the risk of secondary operations, and extending the service life of the tool under complex well conditions.

[0052] In one embodiment, the elastic reset member 820 is in the form of a spring bar with a total compression stroke of 90mm to 130mm and an initial preload of about 8kN to 12kN. It is suitable for conventional fracturing or water injection operations in medium and deep wells and can ensure rapid and uniform retraction of the anchor teeth and the rubber sleeve 833.

[0053] In one embodiment, a plurality of mounting holes are formed at the mounting position, and the plurality of mounting holes are distributed circumferentially at intervals on the connector 810. The number of elastic reset members 820 is the same as that of the mounting holes and they are arranged in a one-to-one correspondence.

[0054] Specifically, one end of each elastic reset member 820 is fixed in the corresponding mounting hole by a threaded fastener, pin or interference fit, and the other end is connected to the corresponding force-bearing part of the setting and anchoring assembly 840, so that each elastic reset member 820 can independently bear and evenly distribute the reset force during axial compression and release.

[0055] During the setting process, when the hydraulic cylinder 700 pushes the cylinder liner 100 and the first locking component 320 to move the connecting seat 810 axially toward the third connection position (i.e., toward the abutment seat 720), the multiple mounting holes on the connecting seat 810 move synchronously with the connecting seat 810. Each elastic reset component 820 is uniformly compressed by the traction force of the mounting holes. Since the mounting holes are uniformly distributed circumferentially, the compression of each elastic reset component 820 remains highly consistent in the circumferential direction, avoiding the phenomenon of uneven load, torsional deformation, or premature failure of a certain elastic reset component 820 caused by single-point or local fixation. During the compression process, the elastic potential energy stored in each elastic reset component 820 is uniformly distributed circumferentially between the connecting seat 810 and the setting anchoring component 840, providing a stable force source for synchronous reset during subsequent unsealing.

[0056] During the unsealing process, after the ball seat unlocking mechanism 400 unlocks the first unlocking component 310 and the first locking component 320, the first locking component 320 (together with the connecting seat 810) gains axial freedom relative to the cylinder liner 100. After the tubing is lifted or hydraulically released, multiple elastic reset components 820 simultaneously release their stored elastic potential energy, and each elastic reset component 820 applies axial tension to the connecting seat 810 through its corresponding mounting hole. Due to the circumferentially uniform distribution of the mounting holes, the tension acts synchronously at all points circumferentially on the connecting seat 810, enabling the connecting seat 810 and the pressure transmission sleeve 830 fixed thereto to move smoothly and without deviation as a whole along the axial direction. As the anchoring assembly 840 loses its continuous axial compressive load, its internal anchoring teeth and sealing sleeve retract radially synchronously under the uniform circumferential reset tension, thus avoiding the local jamming, residual biting on one side of the anchoring teeth, or local adhesion of the sleeve 833 to the inner wall of the sleeve that may occur in traditional single-point or few-point fixing methods, thereby achieving complete and uniform unsealing of the anchoring assembly.

[0057] In this embodiment, by providing multiple circumferentially spaced mounting holes at the mounting position of the connecting seat 810, and fixing each elastic reset member 820 to its corresponding mounting hole, this implementation achieves multi-point, circumferentially balanced application of the reset force. This effectively eliminates problems such as tilting of the connecting seat 810, eccentric sliding of the pressure transmission sleeve 830, or poor local retraction of the setting and anchoring assembly 840 caused by uneven distribution of the reset force. Under complex working conditions such as high pressure, high temperature, or small eccentric loads downhole, the above structure can significantly improve the working synchronization and reliability of the elastic reset member 820, reduce the risk of fatigue fracture or residual deformation caused by local stress concentration during the unsealing process, and thus improve the stability and service life of the entire setting and unsealing device in multiple cycles of operation.

[0058] In one embodiment, the number of mounting holes is set to 12, evenly distributed circumferentially along the connecting seat 810. The hole diameter is 8mm to 12mm, and the hole depth is controlled between 15mm and 25mm. Each mounting hole has a groove communicating with it, and the groove is larger than the mounting hole. The elastic reset member 820 can pass through the mounting hole and extend into the corresponding groove. Each elastic reset member 820 uses a disc spring assembly with a diameter of 6mm to 8mm, which is suitable for conventional fracturing or acidizing operations in medium and deep wells, ensuring sufficient reset force and uniform distribution. In another embodiment, the number of mounting holes is reduced to 8, the circumferential spacing is increased accordingly, and the hole diameter is increased to 12mm to 16mm. It is used with a high-strength helical compression spring with a diameter of 10mm to 12mm, which is suitable for scenarios requiring higher single reset force and a larger total reset stroke in ultra-deep wells or high-temperature and high-pressure conditions.

[0059] In one embodiment, the pressure transmission sleeve 830 is an integrally formed structure, and an array of folded grooves are formed on the pressure transmission sleeve 830.

[0060] Specifically, the folded grooves are regularly distributed along the axial and circumferential directions of the pressure transmission sleeve 830. Each group of folded grooves is composed of multiple axially extending narrow grooves and circumferentially connected annular grooves, forming multiple controllable deformation axial compression units. In the initial relaxed state, the folded grooves maintain a small opening, and the cylinder body is in a rigid cylindrical shape. When subjected to axial compressive load, the folded grooves close under force, and the cylinder wall undergoes controllable folding shortening along the axial direction, thereby realizing the compressive deformation of the pressure transmission sleeve 830 in the axial length, while maintaining circumferential stiffness and overall coaxiality.

[0061] During the setting operation, when the hydraulic cylinder 700 pushes the cylinder liner 100 and the first locking component 320 to move the connecting seat 810 toward the third connection position (i.e., toward the abutment seat 720), the connecting seat 810 simultaneously pulls the upper end of the pressure transmission sleeve 830. The lower end face of the pressure transmission sleeve 830 gradually abuts against the upper end face of the abutment seat 720. As hydraulic pressure continues to be applied, the axial compression force is transmitted along the cylinder. Under the action of compression force, each folded groove closes in sequence, and the cylinder wall is shortened uniformly along the axial direction. The compression amount can be precisely controlled by the depth, width, number, and distribution density of the folded grooves. During the compression process, the cylinder remains continuous and intact in the circumferential direction, without local instability or eccentric deformation. The axial force is uniformly transmitted to the setting anchoring component 840 on the side near the abutment seat 720, so that the anchoring teeth and sealing rubber sleeve are subjected to force and extend outward evenly and adhere tightly to the inner wall of the downhole casing 500, achieving reliable anchoring and annular sealing.

[0062] During the unsealing process, after the ball seat unlocking mechanism 400 unlocks the first unlocking component 310 and the first locking component 320, the connecting seat 810, under the action of the elastic reset component 820, drives the pressure transmission sleeve 830 to move in a direction away from the abutment seat 720. The axial compressive load on the pressure transmission sleeve 830 is gradually released, and each folded groove gradually opens under the combined action of the elasticity of the cylinder wall itself and the external tensile force, and the cylinder body extends uniformly along the axial direction to restore its initial length. Since the folded grooves are evenly distributed in an array, the elongation process is carried out synchronously at all points in the circumference, avoiding the phenomenon of local residual deformation, cylinder wall warping, or additional friction with the central tube 710 that may occur when the sleeve of the traditional split type or without folding structure is unloaded. The smooth reset of the pressure transmission sleeve 830 causes the setting and anchoring assembly 840 to simultaneously lose the axial compressive force, and the anchoring teeth and sealing rubber sleeve can be uniformly and completely radially retracted, achieving a clean and residue-free unsealing.

[0063] In this embodiment, by setting the pressure transmission sleeve 830 as a one-piece molded structure and setting an array of folded grooves on the sleeve wall, this implementation achieves the functions of large axial stroke, controllable compression, and reliable reset while maintaining high circumferential stiffness and overall structural strength. The array arrangement of the folded grooves makes the compression and elongation deformation highly uniform in the circumferential direction, avoiding the problems of limited axial compression capacity and easy occurrence of eccentric load instability of traditional rigid sleeves, or easy loosening, leakage, or fatigue fracture of the connection parts of split sleeves under high pressure. The above structure effectively solves the defects of uneven force transmission during setting leading to weak anchoring and residual deformation causing secondary jamming during unsealing, significantly improving the operational stability and long-term reliability of the device under high pressure, high temperature, and multiple cycle operation conditions, and reducing the risk of unplanned intervention caused by the failure of pressure transmission components in downhole operations.

[0064] In one embodiment, the pressure transmission sleeve 830 includes an extrusion deformation zone 831 and an engagement zone 832 connected in sequence; The setting and anchoring assembly 840 includes: A rubber sleeve 833 is fitted around the outer periphery of the extrusion deformation zone 831. The rubber sleeve 833 extends out and adheres to the inner wall of the downhole casing 500 during the folding and extrusion of the pressure transmission sleeve 830. Multiple anchor blocks 834 are arranged in a circumferential array in the engagement area 832. All anchor blocks 834 can extend radially when the pressure transmission sleeve 830 retracts and abuts against the wall of the downhole casing 500, so as to anchor to the wall of the downhole casing 500.

[0065] Specifically, the setting and anchoring assembly 840 consists of a rubber sleeve 833 and multiple anchor blocks 834. The rubber sleeve 833 is fitted around the outer periphery of the extrusion deformation zone 831 with an interference fit or clearance fit, and its axial length covers the entire extrusion deformation zone 831. Limiting bosses or end face pressure plates are provided at both ends to prevent axial movement. The multiple anchor blocks 834 are evenly distributed in an array along the circumference of the engagement zone 832. The inner surface of each anchor block 834 forms a guiding fit with the outer surface of the engagement zone 832 (usually a bevel or dovetail groove structure), and the outer surface is machined with carbide inserts or serrated engagement surfaces.

[0066] During the setting operation, after the second external ball 20 is set in the pressure-blocking ball seat 730 and hydraulic fluid is pumped, the hydraulic cylinder 700 pushes the cylinder liner 100 and the well pressure-blocking unlocking mechanism 600 to move as a whole towards the third connection position. The first locking component 320 drives the connecting seat 810 to compress the elastic reset component 820 and pulls the pressure transmission sleeve 830 to axially contract towards the abutment seat 720. The lower end face of the pressure transmission sleeve 830 first abuts against the upper end face of the abutment seat 720, forming a stable axial thrust reference. As compression continues, the biting zone 832 first shows a radial outward expansion trend under the force. Multiple anchoring blocks 834 extend outward synchronously along the radial direction under the action of the inner guide slope, and their outer hard tooth tips gradually penetrate and bite into the inner wall of the downhole casing 500, achieving initial mechanical anchoring. Subsequently, the extrusion deformation zone 831 continues to bear the axial compressive load, and the cylinder wall undergoes controlled folding radial outward extrusion deformation along the axial direction. Under the inner compression, the rubber sleeve 833 undergoes volume compression, its radial thickness increases significantly, and it expands outward until its outer surface tightly adheres to the inner wall of the downhole casing 500, forming a reliable annular seal. During this process, the initial engagement of the anchor block 834 provides stable radial support for the rubber sleeve 833, preventing excessive extrusion or local tearing of the rubber sleeve 833 under high pressure. The subsequent expansion of the rubber sleeve 833 further enhances the overall anchoring strength and sealing reliability.

[0067] During the unsealing operation, after the first external ball 10 is seated in the ball groove 420 and the ball seat unlocking mechanism 400 completes the pressure unlocking action, the first unlocking component 310 and the first locking component 320 disengage. Under the action of the potential energy released by the elastic reset component 820, the connecting seat 810 drives the pressure transmission sleeve 830 to reset in a direction away from the abutment seat 720. The axial compressive force on the pressure transmission sleeve 830 is gradually released. The extrusion deformation zone 831 first elastically extends back along the axial direction. After the rubber sleeve 833 loses the radial compressive load, it gradually retracts radially and disengages from the inner wall of the casing with the assistance of its own elasticity and downhole fluid pressure. Subsequently, the biting zone 832 returns to its position with the cylinder. Under the constraint of the inner guide surface, the multiple anchor blocks 834 retract radially in sync, and their outer tooth tips disengage from the biting state of the inner wall of the casing. Since the anchor block 834 and the rubber sleeve 833 are arranged in segments along the axial direction and their deformations are relatively independent, the retraction process does not interfere with each other. This avoids the phenomenon that may occur in traditional integrated anchoring structures during unloading, such as residual deformation of the rubber sleeve 833 blocking the anchor block 834, or the anchor block 834 retracting first, causing the rubber sleeve 833 to be partially adhered and unable to completely detach. This achieves complete and synchronous release of anchoring and sealing.

[0068] In this embodiment, by dividing the pressure transmission sleeve 830 into an extrusion deformation zone 831 and an engagement zone 832, and arranging the rubber sleeve 833 and multiple anchor blocks 834 corresponding to the two zones respectively, this embodiment achieves an orderly sequence of actions: anchoring first and sealing second during the setting process, and sealing first and anchoring second during the unsealing process. This effectively solves the technical defects of traditional sliding sleeve or integrated compression anchoring tools under high pressure, such as "insufficient anchoring leading to slippage" or "difficulty in unsealing after excessive extrusion of the rubber sleeve 833". The above-mentioned segmented and coordinated deformation method significantly improves the device's adaptability to irregularities, ellipticity, and slight diameter reductions in the inner wall of the downhole casing 500. At the same time, it reduces the risk of permanent deformation of the rubber sleeve 833, increased wear of the tooth surface of the anchor blocks 834, or local stress concentration fracture after multiple setting-unsealing cycles, thereby improving the long-term working reliability and reusability of the tool under complex well conditions.

[0069] More specifically, the extrusion deformation zone 831 adopts a structure with a thinner wall thickness (60% to 75% of that of the interlocking zone 832) and a higher density of axial folding grooves. The rubber sleeve 833 is made of high-strength hydrogenated nitrile rubber with a Shore hardness of 85A to 90A and an axial compression ratio designed to be 45% to 55%. The number of anchor blocks 834 is 8 to 12. This is suitable for conventional fracturing or acidizing operations in medium-deep wells and can achieve reliable anchoring and sealing within a casing inner diameter deviation of ±2mm. In another embodiment, the wall thickness of the extrusion deformation zone 831 is appropriately increased, the depth of the folding grooves is increased, the rubber sleeve 833 is made of fluororubber or perfluoroether rubber with a Shore hardness of 92A to 95A, the axial compression ratio is increased to 60% to 70%, and the number of anchor blocks 834 is increased to 16 to 20. This is suitable for ultra-deep wells, high-temperature (≥150℃) or CO2 / H2S corrosive media conditions, and can maintain long-term sealing integrity and anchoring strength in higher pressure differentials and harsher environments.

[0070] Based on the same technical concept, in a third aspect, the present invention also proposes a packer, comprising the well setting and unsetting device described in the second aspect, an upper connector, a release handle, and a lower connector, wherein the release handle, the upper connector, the well setting and unsetting device, and the lower connector are connected in sequence.

[0071] Specifically, the release handle, upper connector, well setting and unsetting device, and lower connector are sequentially connected axially to form a complete tool string. The upper connector is directly connected to the upper part of the tubing string via internal threads; the release handle is located below the upper connector, with its upper end connected to the lower end of the upper connector via a shear pin or a controllable release thread, and its lower end reliably fixed to the upper end of the center tube 710 of the well setting and unsetting device or the upper end face of the hydraulic cylinder 700; the well setting and unsetting device is located entirely below the release handle, with its center tube 710 penetrating the entire length of the tool, and its lower end connected to the lower connector via threads or a stop; the lower end of the lower connector continues to connect to the lower tubing string or other downhole tools.

[0072] Before being lowered into the well, the packer is in a retracted state, the release mechanism remains locked, and the upper connector, release mechanism, well setting and unsealing device, and lower connector form a rigid connection. The pressure transmission sleeve 830 is in an axially stretched position, and the setting and anchoring assembly 840 (rubber sleeve 833 and anchor block 834) is completely retracted within the outer contour of the central tube 710. During the process of lowering the tool to the target formation with the tubing string, the pressure of the fluid column in the central tube 710 and the annulus fluid column is basically balanced, the hydraulic drive assembly does not establish a pressure difference, the ball seat unlocking mechanism 400 and the well pressure release mechanism 600 are both in a locked state, the elastic reset element 820 is in a pre-compressed or free state, and the release shear pin or release thread bears the normal lowering load without moving.

[0073] When the tubing string reaches the predetermined depth and is ready for setting, the second external ball 20 is first lowered into the tubing to set against the pressure-retaining ball seat 730 and seal the lower passage of the central tube 710. Then, working fluid is pumped to establish pressure. The hydraulic pressure acts on the hydraulic cylinder 700, pushing the cylinder liner 100 and the well pressure-retaining unlocking mechanism 600 downwards. The first locking component 320 drives the connecting seat 810 to compress the elastic reset component 820 and pulls the pressure transmission sleeve 830 to contract axially. After the lower end of the pressure transmission sleeve 830 abuts against the abutment seat 720, it continues to be pressurized. The biting zone 832 drives multiple anchor blocks 834 to extend radially outwards and bite against the inner wall of the casing. The extruded deformation zone 831 is then compressed, causing the rubber sleeve 833 to expand radially evenly and adhere to the inner wall of the casing, completing the annular packer. At this point, even when released, the connection remains intact, and the entire packer forms a single unit with the upper tubing string, allowing for subsequent fracturing, acidizing, and injection operations.

[0074] When the operation is completed and the upper tubing string needs to be released and retrieved, the first external ball 10 is lowered into the tubing and set in the ball groove 420, establishing an unlocking pressure differential. The ball seat unlocking mechanism 400 descends to disengage the first unlocking component 310 from the first locking component 320. Under the release of tension by the elastic reset component 820, the connecting seat 810 drives the pressure transmission sleeve 830 to move upward and reset. The setting and anchoring assembly 840 sequentially releases the seal and anchor, and the tool returns to its retracted state. Subsequently, pressurization continues or combined with the lifting operation, so that the axial tension borne by the release hand exceeds the shear strength of the shear pin or releases the thread preset release load. The release hand disengages from the upper connector, and the upper tubing string can be retrieved independently. The well setting and unsealing device, along with the lower connector and the lower tubing string, remain in the well, forming a retrievable or permanent isolation operation mode. If the entire tool needs to be retrieved, the tubing string is directly lifted after unsealing, the release hand remains connected, and the entire tool is retrieved with the tubing string.

[0075] In this embodiment, by setting a release mechanism between the upper connector and the well setting and unsetting device, forming a sequential connection relationship of upper connector—release mechanism—well setting and unsetting device—lower connector, this implementation achieves a flexible operating mode where the upper tubing can be selectively released and retrieved after setting, or the entire tool can be recovered. This effectively solves the technical problem of traditional integrated packers requiring complete retrieval or permanent disposal when unsetting fails or the upper tubing needs to be replaced, resulting in high costs and complex operations. The controllable release function of the release mechanism, combined with the hydraulic setting and elastic reset unsetting characteristics of the well setting and unsetting device, ensures that the tool maintains reliable setting stability and thorough unsetting even under high pressure, high temperature, and sand-bearing well conditions. It also significantly improves tubing recovery efficiency and reduces the number of secondary downhole interventions and operational risks.

[0076] More specifically, the release mechanism employs a single-stage shear pin structure with a shear load set between 180kN and 250kN. The upper connector and release mechanism are connected using a standard API tubing thread, suitable for conventional fracturing or stratified water injection operations in medium-deep wells. The packer as a whole can be recovered ≥3 times. In another embodiment, the release mechanism employs a multi-stage controllable release thread or a hydraulic / mechanical composite release structure, with release loads set in stages of 200kN, 300kN, and 400kN. A rotary guide keyway is added between the upper connector and the release mechanism, suitable for ultra-deep wells or complex segmented fracturing operations requiring multiple release-re-seat cycles. The tool as a whole can achieve more than 5 sets-unseat-release cycles.

[0077] The packer has an overall axial length of 2000mm to 2600mm, with a maximum outer diameter matching the 7-inch casing. The setting and anchoring assembly 840 uses 10 to 14 anchor blocks 834 in conjunction with a single-stage high-strength hydrogenated nitrile rubber sleeve. It has a rated working differential pressure of 70MPa to 90MPa and is suitable for medium-deep well fracturing or water injection operations. In another embodiment, the packer's axial length is increased to 3200mm to 3800mm. The setting and anchoring assembly 840 uses 18 to 24 anchor blocks 834 in conjunction with two-stage or three-stage fluororubber / perfluoroelastomer rubber sleeves connected in series. It has a rated working differential pressure of 120MPa to 160MPa and a temperature resistance of over 180℃, making it suitable for permanent or recyclable packing operations in ultra-deep wells, high-temperature and high-pressure environments, or acidic gas environments.

[0078] The above are merely exemplary embodiments of the present invention and do not limit the scope of the patent of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. An oil well pressure relief unlocking mechanism, characterized in that, include: A cylinder liner, the top and bottom of which form a first connection position and a second connection position respectively. The first connection position can be connected to an external hydraulic cylinder. A sliding space is formed inside the cylinder liner and extends through it along its length. A shearing module is arranged in the area of ​​the sliding space near the second connection position. The shearing modules are arranged at intervals along the length of the cylinder liner. A first locking mechanism is installed at the second connection position. The first locking mechanism includes a first unlocking component and a first locking component. The first unlocking component has a first through hole aligned with the extending direction of the sliding space. The first locking component has a second through hole communicating with the first through hole and aligned with its extending direction. Multiple rings of interlocking teeth are spaced apart along the length of the first unlocking component's sidewall within the first through hole. All interlocking teeth are inclined towards the direction of the first connection position. A ratchet ring is formed on the outer periphery of the first locking component, corresponding to the interlocking teeth. The inclination direction of the ratchet ring is opposite to that of the interlocking teeth. A ball seat unlocking mechanism is slidably installed in the sliding space and located at one end of the shear pin module near the first connection position. A fluid flow channel is formed through the ball seat unlocking mechanism in the same direction as the extension of the cylinder liner. A ball groove is formed at one end of the ball seat unlocking mechanism facing the first connection position. When the first external ball-seat is sealed in the ball groove and the flow channel is blocked to suppress pressure, the ball seat unlocking mechanism slides along the length of the cylinder liner in the sliding space, sequentially shears the shear pin module, and sequentially opens the biting teeth, so that the first unlocking component unlocks the first locking component.

2. The oil well pressure relief unlocking mechanism as described in claim 1, characterized in that, The first locking component includes a sleeve body, in which a second through hole is formed. Multiple ratchet rings are interference-fitted on the outer wall of the sleeve body. All the ratchet rings are distributed at equal intervals along the length direction of the sleeve body, and the diameter of all the ratchet rings decreases sequentially in the direction away from the first unlocking component.

3. The oil well pressure relief unlocking mechanism as described in claim 2, characterized in that, The first unlocking component includes a plurality of first pawls, all of which are circumferentially spaced at the second connection position, and all of which extend along the length of the cylinder liner in a direction away from the second connection position. The end of the first pawl away from the second connection position has a meshing tooth that is the same number as the ratchet ring and meshes with it one by one. Specifically, when the first external ball-slinging seat is sealed in the ball groove and the flow channel is blocked to suppress pressure, and the ball seat unlocking mechanism sequentially cuts the shear pin module, all the first pawls are opened to unlock sequentially with the ratchet ring.

4. The oil well pressure relief unlocking mechanism as described in claim 3, characterized in that, The shearing pin module includes shearing pin rings with the same number of ratchet rings. All the shearing pin rings are spaced apart along the length of the cylinder liner. The spacing between any two adjacent shearing pin rings is the same as the spacing between any two adjacent ratchet rings. Each shearing pin ring has multiple shearing pins spaced apart circumferentially along the sliding space. The ball seat unlocking mechanism includes: A seat body, slidably mounted within the sliding space, wherein the seat body is recessed on the side facing the first connection position toward the second connection position to form the ball groove; and, Multiple unlocking rods are distributed circumferentially at intervals at one end of the base body facing the second connection position. The unlocking rods form a clearance channel that is consistent with the number of shear pins and corresponds one-to-one. All the unlocking rods are integrally formed with the base body. The extension direction of the unlocking rods is consistent with the extension direction of the sliding space, and the unlocking rods can slide with the base body in the sliding space.

5. A device for setting and unsealing an oil well, characterized in that, The well setting and unsetting device is installed inside an external downhole casing, and the well setting and unsetting device includes: Oil well pressure relief unlocking mechanism as described in any one of claims 1 to 4; A hydraulic cylinder body, which is installed at one end of the cylinder liner of the oil well pressure relief unlocking mechanism; A central tube, the cylinder liner being slidably fitted onto the outer periphery of the central tube, a third connection position being formed at the end of the central tube away from the well pressure-locking unlocking mechanism, the third connection position being connectable to an external tubing string, an abutment seat being interference-fitted onto the outer periphery of the central tube near the third connection position, and a pressure-locking ball seat being provided within the cavity of the central tube near the third connection position; and, An anchoring mechanism is sleeved on the outer periphery of the central tube and located between the pressure unlocking mechanism and the abutment seat. One end of the anchoring mechanism is connected to the end of the cylinder sleeve away from the hydraulic cylinder body, and the other end abuts against the abutment seat. The anchoring mechanism has a compressed and folded anchoring state and an extended and reset unlocking state. When the second external ball-throwing seat is sealed to the pressure-blocking ball seat to block pressure, the hydraulic cylinder drives the oil well pressure-blocking unlocking mechanism to move toward the third connection position, so that the anchoring mechanism switches to the anchoring state and anchors to the pipe wall of the downhole casing. When the first external ball-slinging seat is sealed in the ball groove and the flow channel is blocked to suppress pressure, the ball seat unlocking mechanism unlocks the first unlocking component from the first locking component, so that the anchoring mechanism switches from the anchoring state to the unlocking state and is unsealed.

6. The oil well setting and unsealing device as described in claim 5, characterized in that, The anchoring mechanism includes: A connecting seat is slidably sleeved on the outer periphery of the central tube, the connecting seat is connected to the first locking component, and an installation position is formed at the end of the connecting seat away from the first locking component; An elastic reset member, one end of which is connected to the mounting position, extends along the length of the central tube toward the abutment seat; A pressure transmission sleeve, wherein the pressure transmission sleeve is fitted around the outer periphery of the central tube, one end of the pressure transmission sleeve is connected to the connecting seat, and the other end is slidably engaged with the abutment seat; and, A setting and anchoring assembly is mounted on the outer periphery of the pressure transmission sleeve and disposed close to the abutment seat, and the elastic reset member extends to connect with the setting and anchoring assembly. When the second external ball is seated on the pressure-blocking ball seat to block pressure, the hydraulic cylinder drives the well pressure-blocking unlocking mechanism to move the connecting seat toward the third connecting position, causing the pressure transmission sleeve to retract, and when the pressure transmission sleeve abuts against the wall of the downhole casing, the setting and anchoring assembly extends and anchors to the wall of the downhole casing. When the first external ball-seat is sealed in the ball groove and the flow channel is blocked to suppress pressure, the ball seat unlocking mechanism unlocks the first unlocking component from the first locking component, and the elastic reset component drives the seat anchoring assembly to retract and unseal.

7. The oil well setting and unsealing device as described in claim 6, characterized in that, Multiple mounting holes are formed at the mounting position, and the multiple mounting holes are distributed circumferentially at intervals on the connecting seat. The number of elastic reset members is the same as the number of mounting holes and they are set one-to-one.

8. The oil well setting and unsealing device as described in claim 7, characterized in that, The pressure transmission sleeve is a one-piece molded structure, and an array of folded grooves are formed on the pressure transmission sleeve.

9. The oil well setting and unsealing device as described in claim 7, characterized in that, The pressure transmission sleeve includes an extrusion deformation zone and a engagement zone connected in sequence; The setting and anchoring assembly includes: A rubber sleeve, wherein the rubber sleeve is fitted around the outer periphery of the extrusion deformation zone, and the rubber sleeve extends out and conforms to the inner wall of the downhole casing during the folding extrusion of the pressure transmission sleeve; and, Multiple anchor blocks are arranged in a circumferential array in the engagement area. All anchor blocks can extend radially when the pressure transmission sleeve contracts and abuts against the wall of the downhole casing to anchor to the wall of the downhole casing.

10. A packer, characterized in that, It includes an oil well setting and unsetting device as described in any one of claims 5 to 9, an upper connector, a release mechanism, and a lower connector, wherein the release mechanism, the upper connector, the oil well setting and unsetting device, and the lower connector are connected in sequence.

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