High temperature wellbore full circumferential pressure compensation casing packer

Abstract

The present invention relates to the field of underground mining technology. The present invention provides a high-temperature wellbore full-circumferential pressure-compensating casing packer, which includes an anchoring mechanism. The anchoring mechanism includes a slip seat, the slip seat is slidably sleeved on the center pipe and rotates synchronously with the center pipe. The slip seat is located above the straightening sleeve. The slip seat is provided with a plurality of axially spaced slip petals; a scraper is provided on the slip seat and is located between two adjacent slip petals. The outer edge of the scraper is used to abut against the inner wall of the casing; a cone is slidably sleeved on the center pipe and rotates synchronously with the center pipe. The cone is located above the slip seat, the small end of the cone is arranged toward the slip seat, and the large end is connected to the lower end of the rubber cylinder. In the process of scraping impurities, the scraper provided between adjacent slip petals rotates with the center pipe, effectively removing impurities from the inner wall of the casing, avoiding the problem of inconsistent expansion resistance of each slip petal caused by impurities, and creating conditions for the synchronous expansion of the slip petals.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of underground mining technology, and in particular to a high-temperature wellbore full-circumferential pressure-compensating casing packer. Background Art

[0002] In oil and gas extraction and wellbore operations, casing packers are key tools for achieving wellbore stratified isolation and are widely used in processes such as fracturing, acidizing, and stratified oil recovery. Existing slip packers primarily utilize hydraulically driven radial expansion of the slip petals, bringing them into close contact with the inner wall of the casing, thereby achieving the packer's anchoring and sealing functions.

[0003] However, in actual working conditions, the inner wall of the wellbore casing will inevitably contain debris such as scale, rust, and drilling fluid residues, and the distribution of these debris is random and uneven. When the packer moves to the specified position and drives the cava flap to expand, the presence of debris will cause inconsistent contact resistance on each cava flap: the cava flap with larger local resistance will experience expansion lag or insufficient expansion, while the flap with smaller resistance may over-expand. This asynchronous circumferential expansion phenomenon will cause uneven distribution of contact stress on the inner wall of the casing, which will not only cause premature wear or failure of the sealing rubber tube due to eccentric loading, but also cause local stress concentration on the inner wall of the casing, which can easily cause casing damage in long-term use. In addition, the asynchronous expansion of the cava flap will also reduce the anchoring reliability of the packer. In complex wellbore environments such as high temperature and high pressure, the packer may shift or fail, seriously affecting the safety and effectiveness of downhole operations.

[0004] At present, the existing solutions to the technical problem of synchronous expansion of the slip flap in a high-temperature wellbore environment have not yet formed an effective technical means. It is urgent to develop a casing packer that can adapt to the complex conditions of the inner wall of the casing and achieve full circumferential pressure compensation to solve the problem of uneven circumferential force caused by the asynchronous expansion of the slip flap. Summary of the Invention

[0005] To overcome these shortcomings, embodiments of the present invention provide a circumferentially pressure-compensating casing packer for high-temperature wellbores. This solves the existing technical problem of the slips synchronously expanding and anchoring the casing inner wall when the packer is positioned within the casing. However, when scale, rust, or construction debris accumulate on the casing inner wall, the expansion resistance of each petal is inconsistent, causing asynchronous circumferential expansion of the slips and uneven circumferential force on the casing inner wall.

[0006] According to one aspect, at least one embodiment of the present invention provides a high-temperature wellbore circumferential pressure-compensating casing packer for isolating casing, comprising a center pipe and a rubber sleeve, an anchoring mechanism, and a centering sleeve sequentially sleeved along the axial direction of the center pipe; the outer peripheral wall of the centering sleeve is used to abut against the inner wall of the casing to limit the axial position of the centering sleeve; a state switching groove is provided on the peripheral wall of the center pipe, and a state switching block is provided on the peripheral wall of the center pipe that slidably cooperates with the state switching groove, so that the center pipe can move axially along the centering sleeve and rotate circumferentially along the centering sleeve;

[0007] The anchoring mechanism comprises:

[0008] A slip seat is slidably sleeved on the central tube and rotates synchronously with the central tube. The slip seat is located above the centralizing sleeve and is provided with a plurality of axially spaced slip petals.

[0009] a scraper, the scraper being provided on the slip seat and being located between two adjacent slip petals, the outer edge of the scraper being used to abut against the inner wall of the sleeve;

[0010] A cone, which is slidably sleeved on the central tube and rotates synchronously with the central tube, the cone being located above the slip seat, with the small end of the cone facing the slip seat and the large end connected to the lower end of the rubber cylinder;

[0011] Among them, the center tube can drive the rubber cylinder and the anchoring mechanism to rotate under the cooperation of the state switching groove and the state switching block, so as to scrape off impurities on the inner wall of the casing with the help of the scraper, so that the cone can approach and squeeze the upper ends of several of the slip petals under the axial push of the center tube, so that the upper ends of several of the slip petals are deformed and expand away from each other, so as to realize the sealing of the anchoring mechanism.

[0012] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing packer provided in at least one embodiment of the present invention, the state switching groove includes a limiting groove, a transition groove, and a trigger groove that are connected in sequence, the limiting groove and the trigger groove both extend along the axial direction of the centralizing sleeve, and the length of the limiting groove is shorter than the length of the trigger groove; the scraper includes a mounting post and a plate body, the plate body is connected to the upper outer side of the mounting post, and the width of the mounting post in the tangential direction of the slip seat is greater than the width of the plate body;

[0013] A plurality of sliding grooves are provided on the top surface of the slip seat, which are slidably matched with the mounting posts. A first elastic member is provided in the sliding groove, and the first elastic member is used to elastically push the mounting posts. When the state switching block moves from the limit groove to the transition groove, the scraper can slide radially along the slip seat until the plate body abuts against the inner wall of the sleeve.

[0014] The conical surface of the cone has a clearance groove corresponding to the scraper one by one, and the upper part of the clearance groove has two symmetrically arranged guide blocks, and the guide blocks have abutment surfaces extending obliquely downward away from the axis of the slip seat. A avoidance groove for the plate body to pass through is formed between the guide blocks. When the state switching block moves from the transition groove to the trigger groove, the abutment surface is used to abut with the upper end of the mounting column, so that the scraper slides toward the axis of the slip seat when the cone descends, and the plate body is separated from the inner wall of the sleeve.

[0015] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing isolation device provided in at least one embodiment of the present invention, the anchoring mechanism also includes a second elastic member, the two ends of which are respectively connected to the cava seat and the upper end of the cava petal, for elastically pressing the upper end of the cava petal close to the central axis of the cava seat.

[0016] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing packer provided in at least one embodiment of the present invention, a scraping edge is provided on one edge of the plate body away from the mounting column.

[0017] For example, in a high-temperature wellbore circumferential pressure-compensating casing packer provided in at least one embodiment of the present invention, a plurality of accommodating grooves extending axially along the slip seat and used to accommodate the slip petals are provided on the circumferential wall of the slip seat, the accommodating grooves being arranged through the top surface of the slip seat, and the anchoring mechanism further comprising:

[0018] a first slider, the first slider being slidably disposed in the accommodating groove, the lower end of the slip petal being connected to the first slider;

[0019] a first shear pin, the first shear pin penetrating the first slider and the side wall of the receiving groove, and used to limit the position of the first slider in the receiving groove so that the upper end of the slip petal extends upward from the receiving groove;

[0020] Among them, when the pulling force applied to the central tube is greater than the preset shear force of the first shear pin, the first shear pin can break, and then in the process of the central tube driving the cava seat to move upward synchronously, the first slider and the cava flap retract into the accommodating groove to release the seal.

[0021] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing isolation device provided by at least one embodiment of the present invention, the first shear pin includes mounting parts at both ends and a shear part in the middle section, the two mounting parts are respectively connected to the two side walls of the accommodating groove, the shear part is connected to the first slider, and a shear groove is provided between the shear part and the mounting part, and the first shear pin is arranged so that the shear part can break from the shear groove after the force it bears is greater than the preset shear force.

[0022] For example, in the high-temperature wellbore circumferential pressure-compensating casing packer provided in at least one embodiment of the present invention, the slip petals have a limiting surface, and the anchoring mechanism further includes:

[0023] a second slider, the second slider being slidably disposed in the receiving groove;

[0024] a second shear pin, the second shear pin passing through the second slider and having two ends connected to two side walls of the accommodating groove, for limiting the position of the second slider in the accommodating groove;

[0025] Among them, the second shear pin can fix the second slider and the accommodating groove and support it below the limit surface. When the pulling force applied to the center tube is greater than the preset shear force of the second shear pin, the second shear pin can break, and then in the process of the center tube driving the slip seat to move upward synchronously, the second slider and the slip petal retract into the accommodating groove to release the seal.

[0026] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing isolation device provided in at least one embodiment of the present invention, a first slide rail and a second slide rail are provided on the inner side wall of the accommodating groove, and both ends of the first slider are slidably set in the first slide rail, and both ends of the second slider are slidably set in the second slide rail. The first slide rail and the second slide rail can guide the first slider and the second slider to slide in the accommodating groove.

[0027] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing isolation device provided by at least one embodiment of the present invention, the upper end of the cava flap has an extrusion surface facing the axial side of the cava seat and an anchoring surface away from the axial side of the cava seat. The cone can abut against the extrusion surface under the downward movement of the center pipe to cause the cava flap to deform outward and cause the anchoring surface to abut against the inner wall of the casing.

[0028] For example, in the high-temperature wellbore full-circumferential pressure-compensating casing packer provided in at least one embodiment of the present invention, the anchoring surface has a plurality of horizontally extending protruding teeth, and the protruding teeth are used to abut against the inner wall of the casing.

[0029] The beneficial effects of the embodiments of the present invention are:

[0030] In the present invention, the outer peripheral wall of the stabilizing sleeve abuts against the inner wall of the casing, providing a stable axial limit for the packer, ensuring the accurate position of the packer in the wellbore and providing a stable foundation for subsequent scraping and setting operations. The cooperation between the state switching groove and the state switching block enables the central tube to move axially and rotate circumferentially, realizing the orderly switching between the scraping and setting functions. During the scraping process, the scrapers arranged between adjacent slip lobes rotate with the central tube, effectively removing debris from the inner wall of the casing, avoiding the problem of inconsistent expansion resistance of each slip lobes caused by debris, and creating conditions for the synchronous expansion of the slip lobes. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly describes the drawings required for describing the embodiments of the present invention. Obviously, the drawings described below are merely exemplary embodiments of the present invention. Those skilled in the art can, without inventive effort, derive other drawings based on the contents of the exemplary embodiments of the present invention and these drawings.

[0032] Figure 1 Schematic diagram of the overall structure of a high-temperature wellbore full-circumferential pressure-compensating casing packer in one embodiment of the present invention;

[0033] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0034] Figure 3 for Figure 1 A schematic diagram of a first cross-sectional structure of a packer in the embodiment;

[0035] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0036] Figure 5 for Figure 1 A schematic diagram of a second cross-sectional structure of the packer in the embodiment (the second cross-sectional structure is perpendicular to the first cross-sectional structure);

[0037] Figure 6 for Figure 5 Enlarged view of point C in the middle;

[0038] Figure 7 for Figure 1 Schematic diagram of the cone structure of the packer in the embodiment;

[0039] Figure 8 for Figure 1 Schematic diagram of the cone cross-sectional structure of the packer in the embodiment;

[0040] Figure 9for Figure 1 Schematic diagram of the structure of the slip seat and slip petals of the packer in the embodiment;

[0041] Figure 10 for Figure 1 Schematic diagram of the cross-sectional structure of the slip seat and slip petals of the packer in the embodiment;

[0042] Figure 11 for Figure 1 A schematic diagram of the first shear pin structure of the packer in the embodiment;

[0043] Figure 12 for Figure 1 A diagram showing the local structural state of the packer when it is lowered into the casing in the embodiment;

[0044] Figure 13 for Figure 1 Schematic diagram of the second shear pin structure of the packer in the embodiment.

[0045] In the figure: 1, casing, 2, center tube, 3, rubber cylinder, 4, anchoring mechanism, 5, straightening sleeve, 21, state switching block, 50, state switching groove, 51, trigger groove, 52, limit groove, 53, transition groove, 41, slip seat, 42, slip flap, 43, second elastic member, 44, scraper, 45, cone, 441, mounting column, 442, plate, 411, slide groove, 412, first elastic member, 451, give way groove, 4512, guide block, 4511, abutting surface, 4513, avoidance groove, 413, accommodating groove, 46, first slider, 47, first shear pin, 471, mounting portion, 472, shearing portion, 473, shearing groove, 421, limiting surface, 48, second slider, 49, second shear pin, 4131, first slide rail, 4132, second slide rail, 422, extrusion surface, 423, anchoring surface, 4231, convex tooth. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0047] To simplify the drawings, only the parts relevant to the disclosure are schematically shown in each figure; they do not represent the actual structure of the product. Furthermore, to simplify the drawings and facilitate understanding, in some figures, only one of the components with the same structure or function is schematically shown or labeled. In this document, "one" not only means "only one" but also "more than one," and "several" includes "two" and "more than two."

[0048] It should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0049] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0050] In the description of this embodiment, the terms "up", "down", "left", "right", etc., and the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0051] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0052] like Figure 1~Figure 2 The figure shows a high-temperature wellbore full-circumferential pressure-compensating casing packer in one embodiment of the present invention, which is used to isolate casing 1. Its core structure includes a central tube 2 and a rubber sleeve 3, an anchoring mechanism 4, and a centering sleeve 5, which are sequentially arranged axially along the central tube 2. The outer peripheral wall of the centering sleeve 5 abuts the inner wall of the casing 1, thereby limiting the axial position of the centering sleeve 5. A state switching groove 50 is provided on the peripheral wall of the centering sleeve 5, and a state switching block 21 is provided on the peripheral wall of the center tube 2, which slides with the state switching groove 50. This cooperation enables the center tube 2 to move axially and rotate circumferentially along the centering sleeve 5.

[0053] The anchoring mechanism 4 includes a cava seat 41, a scraper 44 and a cone 45. The cava seat 41 is slidably mounted on the center tube 2 and rotates synchronously with the center tube 2. Its position is above the straightening sleeve 5. The cava seat 41 is provided with a plurality of axially spaced cava petals 42. The cava petals 42 are made of flexible material and can be deformed after external force is applied. The scraper 44 is installed on the cava seat 41 and is located between two adjacent cava petals 42. The outer edge of the scraper 44 can contact the inner wall of the sleeve 1. The cone 45 is also slidably mounted on the center tube 2 and rotates synchronously with the center tube 2. It is above the cava seat 41, with its small end facing the cava seat 41 and the large end connected to the lower end of the rubber cylinder 3.

[0054] After the packer is lowered into the wellbore, the outer circumferential wall of the centering sleeve 5 abuts against the inner wall of the casing 1, preliminarily defining the axial position of the packer. At this point, the state switching block 21 on the center pipe 2 is located at one end of the state switching groove 50 of the centering sleeve 5. By applying external force, the center pipe 2 rotates circumferentially along the centering sleeve 5, and the state switching block 21 slides within the state switching groove 50, driving the rubber sleeve 3 and the anchoring mechanism 4 to rotate together. During the rotation process, the outer edge of the scraper 44 contacts the inner wall of the casing 1. As the center pipe 2 rotates, the scraper 44 scrapes away impurities such as scale, rust, and drilling fluid residue on the inner wall of the casing 1, clearing obstacles for the subsequent uniform expansion of the slip flap 42.

[0055] After the impurities are scraped off, the center tube 2 is pushed to move axially along the straightening sleeve 5, and the position of the state switching block 21 in the state switching groove 50 changes, causing the cone 45 to move in the direction close to the slip seat 41. The small end of the cone 45 gradually approaches the upper end of the slip flap 42, exerting an extrusion force on the upper end of the slip flap 42. Since the slip flaps 42 are axially spaced on the slip seat 41, and the extrusion of the cone 45 is evenly transmitted to each slip flap 42, and since the slip flap 42 is made of flexible metal, the upper end of the slip flap 42 can be deformed and expand away from each other, and finally the outer side of the slip flap 42 is in close contact with the inner wall of the casing 1, realizing the setting of the anchoring mechanism 4. Then, the rubber cylinder 3 is compressed under the action of the continuous axial movement of the center tube 2, and fits tightly with the inner wall of the casing 1, realizing the sealing function.

[0056] The outer peripheral wall of the straightening sleeve 5 abuts against the inner wall of the casing 1, providing a stable axial limit for the packer, ensuring the accurate position of the packer in the wellbore, and providing a stable foundation for the subsequent scraping of impurities and setting operations. The cooperation between the state switching groove 50 and the state switching block 21 enables the central tube 2 to move axially and rotate circumferentially, realizing the orderly switching of the two functions of scraping impurities and setting. During the scraping process, the scraper 44 arranged between adjacent slip flaps 42 rotates with the central tube 2, effectively removing debris from the inner wall of the casing 1, avoiding the problem of inconsistent expansion resistance of each slip flap 42 caused by debris, and creating conditions for the synchronous expansion of the slip flaps 42.

[0057] The design of the small end of the cone 45 facing the slip seat 41 allows the cone 45 to evenly squeeze the upper end of each slip flap 42 when the center tube 2 pushes the cone 45 axially. Because the slip flaps 42 are axially spaced apart, the squeezing force of the cone 45 can be transmitted relatively evenly to each slip flap 42, reducing the phenomenon of asynchronous expansion caused by resistance differences. When the upper ends of the slip flaps 42 deform and expand away from each other, the contact stress distribution between each slip flap 42 and the inner wall of the casing 1 is more uniform, thereby reducing the possibility of premature wear or failure of the sealing rubber sleeve 3 due to eccentric loading, and also reducing the problem of local stress concentration on the inner wall of the casing 1, thereby increasing the service life of the casing 1.

[0058] The uniform expansion of the slips 42 in the anchoring mechanism 4 significantly improves the packer's anchoring reliability. In complex wellbore environments such as high temperature and high pressure, this effectively prevents packer displacement or failure due to asynchronous expansion of the slips 42, ensuring the safety and effectiveness of downhole operations. Through the coordinated action of various components, the packer achieves full circumferential pressure compensation, resolving the problem of uneven circumferential force caused by asynchronous circumferential expansion of the slips 42 in existing technologies.

[0059] like Figure 3 、 Figure 4 、 Figure 7 、 Figure 8 and Figure 12 As shown, a state switching groove 50 is provided on the peripheral wall of the centralizing sleeve 5. This groove is composed of an axially extending limit groove 52, an arcuate transition groove 53, and an axial trigger groove 51, which are connected in sequence. The axial length of the limit groove 52 is required to ensure that the state switching block 21 of the central pipe 2 is retained within the limit groove 52 under the action of gravity and fluid when the packer is lowered into the casing, thereby preventing premature activation of the anchoring mechanism 4. The transition groove 53 connects the limit groove 52 and the trigger groove 51, providing a guide path for the circumferential rotation of the central pipe 2. The trigger groove 51 extends axially and is longer than the limit groove 52, providing sufficient travel space for the axial movement of the central pipe 2.

[0060] The scraper 44 includes a mounting post 441 that slides with the slot 411 on the top surface of the slip seat 41, and a plate 442 fixed to the outer side of its upper portion. A first elastic member 412 is disposed within the slot 411, one end of which is connected to the inner wall of the slot 411 and the other end abuts the mounting post 441. Under normal conditions, the mounting post 441 is pushed away from the axis of the slip seat 41. However, since the upper end of the mounting post 441 is in contact with the abutment surface 4511 at this time, the plate 442 is in a retracted state. The edge of the plate 442 away from the mounting post 441 is provided with a scraping blade that matches the curvature of the inner wall of the casing 1. The direction of the blade edge is consistent with the rotation direction of the scraper 44, forming a shearing and cutting structure for impurities on the inner wall of the casing 1.

[0061] When the packer reaches the designated position, the central tube 2 is pulled up, causing the state switching block 21 to disengage from the limiting groove 52 and enter the transition groove 53. At this point, the first elastic member 412 can push the mounting post 441 to slide radially along the slide groove 411. The central tube 2 then rotates circumferentially, driving the scraper 44 to rotate synchronously, causing the outer edge of the scraping blade to contact the inner wall of the casing 1. This circumferential rotation scrapes away impurities such as scale and rust. After the scraping operation is completed, the central tube 2 is further pressed, causing the state switching block 21 to enter the trigger groove 51 from the transition groove 53. The central tube 2 moves axially, driving the cone 45 downward. The guide block 4512 on the cone 45's conical surface, through the inclined abutment surface 4511, pushes the mounting post 441 to slide toward the axial center, overcoming the elastic force of the first elastic member 412. The plate 442 then disengages from the inner wall of the casing 1 and passes through the avoidance groove 4513 between the guide blocks 4512, completing the retraction of the scraper 44 and freeing up circumferential space for the expansion of the slip flaps 42.

[0062] The segmented mechanical structure of the state switching groove 50 cooperates with the scraper 44 to achieve orderly functional switching of the packer from lowering and positioning to impurity removal and then to setting and anchoring: the limit groove 52 prevents the anchoring mechanism 4 from being triggered incorrectly through axial constraint, ensuring that the packer safely reaches the target position; the guidance of the transition groove 53 enables the scraper 44 to fully adhere to the inner wall of the casing 1 when the central pipe 2 rotates, and cooperates with the shearing and cutting action of the scraping blade to effectively remove impurities on the inner wall, solving the problem of uneven expansion resistance of the slip flap 42 caused by impurities in the prior art. The pushing action of the first elastic member 412 enables the scraper 44 to adapt to the irregular surface of the inner wall of the casing 1, ensuring close contact between the scraping blade and the inner wall and improving the efficiency of impurity removal; the abutment cooperation between the guide block 4512 of the cone 45 and the mounting column 441 realizes the automatic retraction of the scraper 44 through mechanical linkage, avoiding the interference of the scraping component with the expansion path of the slip flap 42, and creating a clean and unobstructed environment for the subsequent uniform circumferential expansion of the anchoring mechanism 4.

[0063] The synergistic effect of these components forms a complete pretreatment mechanism. The sliding fit between the state switching block 21 and the state switching groove 50 precisely controls process transitions. The elastic sliding structure of the scraper 44 and the cutting design of the scraping edge eliminate the problem of impurity interference. The guiding structure of the yield groove 451 of the cone 45 ensures interference-free switching of functional modules. This design structurally eliminates the potential risk of asynchronous expansion of the slip flaps 42 caused by debris on the inner wall of traditional packers. This reduces the difference in contact resistance between the circumferential slip flaps 42 during setting, significantly improving the synchronization and reliability of the anchoring mechanism 4, thereby reducing the off-center load wear of the sealing rubber sleeve 3 and extending its service life in high-temperature wellbores.

[0064] like Figure 5 、 Figure 6 、 Figures 9 to 11 and Figure 13 As shown, a receiving groove 413 is defined in the peripheral wall of the slip seat 41 and extends axially through the top surface. The first slider 46 is slidably disposed within the receiving groove 413. The lower end of the slip petal 42 is connected to the first slider 46 via a fixed structure. The mounting portions 471 at both ends of the first shear pin 47 have an interference fit with the side walls of the receiving groove 413. The middle shear portion 472 extends through the pin hole preset in the first slider 46. The shear groove 473 between the shear portion 472 and the mounting portion 471 forms a stress concentration area with a narrowed diameter. In the normal sealing state, the first shear pin 47 limits the axial movement of the first slider 46 in the accommodating groove 413, so that the upper end of the cava flap 42 remains in an extended state; when the cava flap 42 is stuck by impurities on the inner wall of the casing 1 or the second elastic member 43 is fatigued and cannot be retracted by elastic reset, the central tube 2 is pulled up to drive the cava seat 41 to move up synchronously, and the axial tension exerted on the first slider 46 is transmitted to the shear portion 472 through the pin hole. When the tension exceeds the preset shear force of the shear groove 473, the shear portion 472 breaks from the shear groove 473, and the first slider 46 loses its limit. During the upward movement of the central tube 2, it slides along the guide structure in the accommodating groove 413, driving the lower end of the cava flap 42 to retract into the inside of the accommodating groove 413, thereby achieving forced unsealing.

[0065] The design of the first shear pin 47 establishes a mechanical rupture release mechanism: under normal operating conditions, the elastic force of the second elastic member 43 retracts the slip flap 42. Under abnormal operating conditions, the pin is pulled up to trigger the rupture of the pin, achieving forced retraction, thus avoiding unsealing failure caused by the failure of a single reset method. The stress concentration structure of the shear groove 473 ensures that the pin breaks precisely under the preset load, maintaining the stability of the set state while providing a reliable unsealing redundancy solution for complex operating conditions. This significantly improves the unsealing reliability of the packer under extreme conditions such as downhole impurity accumulation and elastic member performance degradation, thereby reducing operational risks.

[0066] The mounting portion 471 of the first shear pin 47 is secured to the sidewall of the receiving groove 413 using an interference fit process, ensuring that the pin will not be displaced by vibration or axial load during the setting process. The shear portion 472 has a smaller diameter than the mounting portion 471. The shear groove 473 in the transition area between the two is a single-sided or annular groove, with its depth and width parameterized according to the target shear force. When the first slider 46 is subjected to axial tension, the shear force is concentrated at the minimum cross-sectional area of ​​the shear groove 473. When the shear strength of the material is exceeded, the shear force breaks, separating the mounting portion 471 from the shear portion 472 and releasing the sliding freedom of the first slider 46.

[0067] The hierarchical design of the shear pins enables precise control of the load transfer path. By optimizing the geometric parameters of the shear groove 473, the preset shear force can be adjusted for different wellbore operating conditions, adapting the packer to diverse operational requirements. The precise placement of stress concentration zones prevents accidental pin breakage under non-target loads while ensuring reliable failure when release is required. This balances setting stability with release controllability, enhancing the packer's adaptability to various operating conditions and operational safety.

[0068] The limiting surface 421 at the lower end of the slip flap 42 is a horizontally extending stepped structure. The second slider 48 is matched and arranged in the receiving groove 413 below the limiting surface 421. Its top surface contacts the limiting surface 421 to limit the downward displacement of the slip flap 42. The second shear pin 49 has the same structure as the first shear pin 47. The two ends of the second shear pin 49 are fixed to the side walls of the receiving groove 413. The middle section of the second shear pin 49 extends through the pin hole of the second slider 48. The breaking groove of the second shear pin 49 is also located in the transition area between the two ends and the middle section. During normal operation, the second shear pin 49 and the first shear pin 47 jointly limit the axial position of the slip flap 42. When the pulling force of the central tube 2 exceeds the preset shear force of the second shear pin 49 and the first shear pin 47, the two pins break simultaneously, and the second slider 48 and the first slider 46 simultaneously drive the lower end of the slip flap 42 to retract into the receiving groove 413.

[0069] The combined design of double shear pins and double sliders forms double limit protection. The supporting effect of the second slider 48 on the limit surface 421 effectively resists the axial impact of the downhole high-pressure fluid on the slip flap 42, prevents the slip flap 42 from being displaced due to excessive axial load, and enhances the high-pressure stability of the anchoring mechanism 4.

[0070] The first and second slide rails 4131 and 4132 on the inner sidewalls of the receiving groove 413 are both T-shaped grooves extending axially through the grooves. The first slider 46 has protrusions on both ends that match the first slide rail 4131 and slide into the groove structure to ensure that it does not deviate from the track during radial movement. The second slider 48 has the same sliding structure as the first slider 46 and is adapted to the second slide rail 4132.

[0071] The anti-detachment design of the T-groove and the protrusion eliminates the risk of the slider falling off during high-speed movement or vibration environments, ensuring the accuracy of the motion trajectory of the slip flap 42. The high-precision guide surface significantly reduces the sliding friction coefficient, so that the difference in motion resistance of each slip flap 42 under the same driving force is controlled within a very small range, avoiding the problem of asynchronous expansion caused by uneven friction. The dual slide rails guide the first slider 46 and the second slider 48 respectively, forming a bidirectional constraint on the upper and lower ends of the slip flap 42, improving its posture stability during radial expansion and ensuring uniform contact between the anchor surface 423 and the inner wall of the casing 1.

[0072] like Figures 9 and 10 As shown, the extrusion surface 422 at the upper end of the slip flap 42 matches the angle of the cone 45. When the cone 45 moves axially, the extrusion surface 422 converts the axial thrust into a radial expansion force, causing the anchoring surface 423 on the outer side of the slip flap 42 to fit the inner wall of the casing 1. The anchoring surface 423 is provided with inverted teeth 4231, with narrow tips and wide roots. The teeth are evenly distributed along the circumference and the tooth height is adapted to the roughness of the inner wall of the casing 1, ensuring that the tips of the teeth 4231 form a mechanical engagement with the inner wall during expansion.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A high-temperature wellbore full-circumferential pressure-compensating casing packer for isolating a casing (1), characterized in that: It comprises a central tube (2) and a rubber sleeve (3), an anchoring mechanism (4) and a straightening sleeve (5) which are sequentially sleeved along the axial direction of the central tube (2); the outer peripheral wall of the straightening sleeve (5) is used to abut against the inner wall of the sleeve (1) to limit the axial position of the straightening sleeve (5); a state switching groove (50) is provided on the peripheral wall of the straightening sleeve (5); a state switching block (21) which is slidably matched with the state switching groove (50) is provided on the peripheral wall of the central tube (2); the central tube (2) can move axially along the straightening sleeve (5) and rotate circumferentially along the straightening sleeve (5); The anchoring mechanism (4) comprises: a slip seat (41), the slip seat (41) being slidably sleeved on the central tube (2) and rotating synchronously with the central tube (2), the slip seat (41) being located above the centralizing sleeve (5), and the slip seat (41) being provided with a plurality of slip petals (42) arranged axially at intervals; a scraper (44), the scraper (44) being provided on the slip seat (41) and being located between two adjacent slip petals (42), the outer edge of the scraper (44) being used for abutting against the inner wall of the sleeve (1); A cone (45), the cone (45) is slidably sleeved on the central tube (2) and rotates synchronously with the central tube (2), the cone (45) is located above the slip seat (41), the small end of the cone (45) is arranged toward the slip seat (41), and the large end is connected to the lower end of the rubber cylinder (3); The center tube (2) can drive the rubber cylinder (3) and the anchor mechanism (4) to rotate under the cooperation of the state switching groove (50) and the state switching block (21), so as to scrape off impurities on the inner wall of the sleeve (1) with the help of the scraper (44), so that the cone (45) can approach and squeeze the upper ends of the plurality of slip flaps (42) under the axial pressure of the center tube (2), so that the upper ends of the plurality of slip flaps (42) are deformed and expand away from each other, so as to realize the setting of the anchor mechanism (4); The state switching groove (50) includes a limiting groove (52), a transition groove (53) and a triggering groove (51) which are connected in sequence, the limiting groove (52) and the triggering groove (51) both extending along the axial direction of the straightening sleeve (5), and the length of the limiting groove (52) is shorter than the length of the triggering groove (51); the scraper (44) has a mounting column (441) and a plate body (442), the plate body (442) is connected to the upper outer side of the mounting column (441), and the width of the mounting column (441) is greater than the width of the plate body (442) in the tangential direction of the slip seat (41); A plurality of sliding grooves (411) are provided on the top surface of the cava seat (41) and are slidably matched with the mounting posts (441). A first elastic member (412) is provided in the sliding groove (411). The first elastic member (412) is used to elastically push the mounting posts (441). When the state switching block (21) moves from the limiting groove (52) to the transition groove (53), the scraper (44) can slide radially along the cava seat (41) to the plate body (442) and abut against the inner wall of the sleeve (1). The conical surface of the cone (45) has a clearance groove (451) corresponding to the scraper (44) one by one, and the upper part of the clearance groove (451) has two symmetrically arranged guide blocks (4512), and the guide blocks (4512) have abutment surfaces (4511) extending obliquely downward away from the axis of the cava seat (41). A avoidance groove (4513) for the plate body (442) to pass through is formed between the guide blocks (4512). When the state switching block (21) moves from the transition groove (53) to the trigger groove (51), the abutment surface (4511) is used to abut against the upper end of the mounting column (441), so that the scraper (44) slides toward the axis of the cava seat (41) when the cone (45) descends, and the plate body (442) is separated from the inner wall of the sleeve (1).

2. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 1, characterized in that: The anchoring mechanism (4) further comprises a second elastic member (43), the two ends of which are respectively connected to the upper end of the slip seat (41) and the slip flap (42), and are used for elastically pressing the upper end of the slip flap (42) close to the central axis of the slip seat (41).

3. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 2, characterized in that: A scraping blade is provided on one side edge of the plate body (442) away from the mounting post (441).

4. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 1, characterized in that: A plurality of receiving grooves (413) extending axially along the slip seat (41) and used to receive the slip flaps (42) are provided on the peripheral wall of the slip seat (41). The receiving grooves (413) are provided through the top surface of the slip seat (41). The anchoring mechanism (4) further comprises: a first slider (46), the first slider (46) being slidably disposed in the accommodating groove (413), the lower end of the slip flap (42) being connected to the first slider (46); a first shear pin (47), the first shear pin (47) penetrating the first slider (46) and the side wall of the accommodating groove (413), and used for limiting the position of the first slider (46) in the accommodating groove (413) so that the upper end of the slip flap (42) extends upward from the accommodating groove (413); When the pulling force applied to the center tube (2) is greater than the preset shear force of the first shear pin (47), the first shear pin (47) can break, and then, in the process of the center tube (2) driving the cava seat (41) to move upward synchronously, the first slider (46) and the cava flap (42) are retracted into the accommodating groove (413) to release the seal.

5. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 4, characterized in that: The first shear pin (47) comprises mounting portions (471) at both ends and a shearing portion (472) in the middle, the two mounting portions (471) being respectively connected to the two side walls of the accommodating groove (413), the shearing portion (472) being connected through the first slider (46), a shearing groove (473) being provided between the shearing portion (472) and the mounting portion (471), and the first shear pin (47) being arranged so that the shearing portion (472) can break from the shearing groove (473) when the force borne by the shearing portion (472) is greater than a preset shearing force.

6. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 5, characterized in that: The slip flap (42) has a limiting surface (421), and the anchoring mechanism (4) further comprises: a second slider (48), the second slider (48) being slidably disposed in the accommodating groove (413); a second shear pin (49), the second shear pin (49) passing through the second slider (48) and having two ends of the second shear pin (49) respectively connected to two side walls of the accommodating groove (413), for limiting the position of the second slider (48) in the accommodating groove (413); The second shear pin (49) can fix the second slider (48) and the accommodating groove (413) and support it below the limit surface (421). When the pulling force on the center tube (2) is greater than the preset shear force of the second shear pin (49), the second shear pin (49) can break, and then, in the process of the center tube (2) driving the cava seat (41) to move upward synchronously, the second slider (48) and the cava flap (42) are retracted into the accommodating groove (413) to release the seal.

7. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 6, characterized in that: The inner side wall of the accommodating groove (413) is provided with a first slide rail (4131) and a second slide rail (4132), the two ends of the first slider (46) are slidably arranged in the first slide rail (4131), and the two ends of the second slider (48) are slidably arranged in the second slide rail (4132), and the first slide rail (4131) and the second slide rail (4132) can guide the first slider (46) and the second slider (48) to slide in the accommodating groove (413).

8. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 1, characterized in that: The upper end of the cava flap (42) has an extrusion surface (422) facing the axial side of the cava seat (41) and an anchoring surface (423) away from the axial side of the cava seat (41). The cone (45) can abut against the extrusion surface (422) when the central tube (2) moves downward, so that the cava flap (42) is deformed outward, and the anchoring surface (423) abuts against the inner wall of the sleeve (1).

9. The high-temperature wellbore full-circumferential pressure-compensating casing packer according to claim 8, characterized in that: The anchoring surface (423) is provided with a plurality of horizontally extending protruding teeth (4231), and the protruding teeth (4231) are used to abut against the inner wall of the sleeve (1).

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