Anti-clamping anchoring tool

Abstract

The invention discloses an anti-clamping anchoring tool. The tool comprises a central pipe, a thrust assembly, an anchoring mechanism and a piston assembly, wherein the thrust assembly, the anchoring mechanism and the piston assembly are arranged on the central pipe in a sleeving mode. A first piston mechanism of the piston assembly comprises a first piston seat, a first piston sleeve and a first outer cylinder which are connected. The upper end of the central pipe is connected with the thrust assembly, and the lower end of the central pipe is connected with the first piston sleeve; the first piston seat, the center pipe, the first piston sleeve and the first outer cylinder form a first annular space communicating with the center flow channel, and a second annular space and a third annular space communicating with the external environment are formed among the anchoring mechanism, the center pipe and the first piston seat, the first piston sleeve and the first outer cylinder. After the anchoring mechanism and the external sleeve are anchored through pressure boosting in the pipe, when hydraulic pressure acts on the annular space, anchoring of the anchoring mechanism is stable or reinforced; and when the central pipe is lifted, the anchoring mechanism is released from anchoring through the thrust assembly. The anchoring safety and reliability can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field exploration and development, and particularly relates to an anti-sticking anchoring tool. Background Art

[0002] In oil and gas field development, anchoring tools such as two-way anchors and hydraulic anchors need to be equipped for stratified water injection, fracturing and other measure strings, so that the measure strings are anchored on the casing wall, preventing the measure strings from creeping repeatedly under the action of stress such as piston effect, expansion effect, and temperature effect due to pressure and temperature fluctuations, and further preventing the packer tool in the measure string from creeping and failing.

[0003] The working principle of the existing anchoring tools is as follows: Under the action of hydraulic pressure, the piston and the connected cone are pushed to move, the two-way anchor tiles are forced out and stuck on the inner wall of the casing to achieve anchoring, and the cone is prevented from moving back and the two-way anchor tiles from retracting; during production, the up-pulling axial force generated by the measure string due to stress such as expansion effect and temperature effect is transmitted to the two-way anchor tiles and the casing through the unlocking shear pins, avoiding the creeping of the measure string and protecting the packer in the measure string; during well workover operation to lift the pipe string later, a certain pulling force needs to be applied to cut the unlocking shear pins, and then drive the piston and the connected cone to move up, making room for the two-way anchor tiles to retract and release the anchoring. Summary of the Invention

[0004] The inventors of the present application found that for the existing anchoring tools that use unlocking shear pins to counteract the stress effects such as piston effect, expansion effect, and temperature effect, if the shear force of the unlocking shear pins is set to be small, the anchoring tool is prone to creep under the action of external forces, causing the measure string to be prematurely released from anchoring; when the shear force of the unlocking shear pins is set to be large, a sufficiently large pulling force is required to cut the unlocking shear pins during unlocking. Due to the limited tensile resistance of the workover derrick or the pipe string, it is difficult to cut the unlocking shear pins, which is likely to cause the pipe string to get stuck or break, resulting in major repairs. Moreover, due to the complex downhole working environment, it is difficult to determine the unlocking shear pin structure that is exactly adapted to the downhole environment; therefore, it is necessary to design an anchoring tool that can meet the complex downhole anchoring environment and can be successfully unlocked when unlocking is required.

[0005] In view of the above problems, the present invention is proposed to provide an anti-sticking anchoring tool that overcomes the above problems or at least partially solves the above problems.

[0006] In a first aspect, an anti-sticking anchoring tool according to an embodiment of the present invention includes a central tube, and a thrust assembly, an anchoring mechanism, and a piston assembly that are sequentially sleeved on the central tube;

[0007] The central tube includes: a first central tube and a second central tube sleeved on the first central tube;

[0008] The thrust assembly is sleeved on the first central tube, and the lower end is fixedly connected to the second central tube;

[0009] The anchoring mechanism is sleeved on the second central tube;

[0010] The inner holes of the first central tube and the piston assembly form a central flow channel;

[0011] The piston assembly includes at least a first piston mechanism, and the first piston mechanism includes: a first piston seat, a first piston sleeve and a first outer cylinder which are connected; the first piston seat is fixedly connected to the first outer cylinder, and the first piston sleeve is arranged in the cavity of the first outer cylinder;

[0012] The lower end of the second central tube is fixedly connected to the first piston sleeve through a connecting cylinder; the lower end of the anchoring mechanism is fixedly connected to the first piston seat;

[0013] A first annular space is formed among the first piston seat, the second central tube, the first piston sleeve and the first outer cylinder, and the first annular space is communicated with the central flow channel through a first liquid inlet hole arranged on the connecting cylinder. A second annular space is formed among the anchoring mechanism, the second central tube and the first piston seat. A third annular space is formed between the first piston sleeve and the first outer cylinder. The second annular space and the third annular space are communicated with the external environment;

[0014] Under the pressurized state of the central flow channel, the hydraulic pressure pushes the first piston sleeve to drive the second central tube and the thrust assembly to move downward, and the thrust assembly pushes the anchoring mechanism to move, so that the anchoring mechanism is anchored with the external casing; and after the anchoring mechanism is anchored with the casing, under the state that the hydraulic pressure acts on the first annular space, the second annular space and the third annular space, the anchoring of the anchoring mechanism is stable or strengthened;

[0015] When the first central tube is lifted, it drives the thrust assembly to move upward so as to release the anchoring of the anchoring mechanism with the casing.

[0016] In an optional embodiment, sealing rings are arranged between the first piston seat and the central tube and the first outer cylinder, and between the first piston sleeve and the first outer cylinder.

[0017] In an optional embodiment, the piston assembly further includes: at least one second piston mechanism, and the second piston mechanism includes: a second piston seat, a second piston sleeve and a second outer cylinder;

[0018] The second piston sleeve is connected to the first piston sleeve. The second piston seat is sleeved on the first piston sleeve, and the second outer cylinder is connected to the first outer cylinder through the second piston seat. A fourth annular space is formed between the second piston seat and the first piston sleeve, and the fourth annular space communicates with the third annular space;

[0019] A fifth annular space is formed among the first piston sleeve, the second piston seat and the second piston sleeve, and a second liquid inlet hole is provided on the first piston sleeve to communicate the fifth annular space with the central flow channel;

[0020] A sixth annular space communicating with the external environment is formed between the second outer cylinder and the second piston sleeve;

[0021] Correspondingly, when the second piston mechanism is set to two or more, the liquid inlet hole of the piston mechanism located below is provided on the piston sleeve of the piston mechanism located above it.

[0022] In an optional embodiment, air holes are provided on the outer cylinder and / or the piston seat of the piston assembly.

[0023] In an optional embodiment, the above anti-sticking anchoring tool further includes: an upper sub and a lower sub;

[0024] The upper sub is fixedly connected to the first central tube, and the lower sub is fixedly connected to the piston assembly;

[0025] A limiting step is provided on the first central tube; a first step is provided on the second central tube;

[0026] When the first central tube is lifted, the thrust assembly and the second central tube are driven to move upward through the limiting step, and the second central tube drives the anchoring mechanism to move through the first step, so that the anchoring mechanism is disengaged from the casing.

[0027] In an optional embodiment, the anchoring mechanism includes: a slip housing, a support cone, slips and a slip seat;

[0028] The slip housing is sleeved on the second central tube, and an annular cavity is formed between the slip housing and the second central tube, and its lower end is fixedly connected to the first piston seat;

[0029] The support cone, the slips and the slip seat are sequentially arranged in the annular cavity, and an anchor window for the radial extension of the slips is provided on the slip housing;

[0030] The support cone abuts against the thrust assembly, and the slip seat abuts against the first piston seat.

[0031] In an alternative embodiment, a plurality of T-shaped key grooves are provided at one end of the support cone close to the slips.

[0032] Correspondingly, a connecting key adapted to the T-shaped key groove is provided at one end of the slips, so as to be clamped in the T-shaped key groove through the connecting key, and the abutting surface of the connecting key and the bottom of the T-shaped key groove is a conical surface.

[0033] In an alternative embodiment, the cone angle of the conical surface is 8° to 12°.

[0034] In an alternative embodiment, the thrust assembly includes: an outer sleeve, a support seat, and a lock block sleeve;

[0035] The outer sleeve is respectively connected to the upper sub and the slips housing, the lock block sleeve is arranged inside the outer sleeve and connected to the first central tube through a lock block;

[0036] The support seat is arranged in an annular cavity formed by the first central tube, the outer sleeve, the lock block sleeve and the support cone. The support seat is connected to the outer sleeve through an anchor shear pin, and its lower end is connected to the second central tube;

[0037] A lock ring is arranged on the inner wall of the support seat. Correspondingly, lock teeth adapted to the lock ring are arranged on the inner wall of the first central tube, so as to limit the upward movement of the support seat relative to the first central tube through the cooperation of the lock ring and the lock teeth.

[0038] In an alternative embodiment, an anti-top lock ring is arranged on the inner wall of the outer sleeve;

[0039] Correspondingly, anti-top lock teeth adapted thereto are arranged on the outer wall of the upper sub, so as to limit the upward movement of the outer sleeve relative to the central tube through the cooperation of the anti-top lock ring and the anti-top lock teeth.

[0040] In an alternative embodiment, a first step is arranged on the second central tube, and a second step adapted to the first step is arranged on the support cone, so as to limit the downward movement of the support cone through the cooperation of the first step and the second step, and drive the support cone to move upward when the second central tube moves upward.

[0041] The beneficial effects of the above technical solutions provided by the embodiments of the present invention at least include:

[0042] The anti-sticking anchoring tool provided by the embodiment of the present invention forms a first annular space between the first piston seat, the central tube, the first piston sleeve and the first outer cylinder, and the first annular space is communicated with the central flow channel; and a second annular space is formed between the anchoring mechanism, the central tube and the first piston seat, and a third annular space is formed between the first piston sleeve and the first outer cylinder. The second annular space and the third annular space are communicated with the external environment. Under the pressurized state of the central flow channel, the first piston seat squeezes the anchoring mechanism upward, and the first piston sleeve drives the central tube and the thrust assembly to move downward to push the anchoring mechanism to expand radially and anchor with the external casing; in the production state such as water injection where the internal pressure is greater than the external pressure, the pressure acts on the first annular space, the first piston sleeve generates a downward force and transmits it to the second central tube connected thereto, and acts on the thrust assembly through the second central tube, which can be used to balance the upward force under the action of the expansion effect and temperature effect, etc. when the upper pipe string acts on the first central tube under the condition that the internal pressure is greater than the external pressure and acts on the thrust assembly through the first central tube; and at this time, the first piston seat generates an upward thrust, which acts on the anchoring mechanism and can make the anchoring of the anchoring mechanism with the external casing more reliable; and the anti-sticking anchoring tool of the embodiment of the present invention does not set an unlocking shear pin, and relies on its own structure to offset the acting forces generated by the downhole expansion effect and temperature effect, etc., and in the later stage of pipe lifting operation, there is no need to apply an unlocking load, and directly lifting the central tube can drive the thrust assembly to move upward to achieve safe unlocking, eliminating the risk that the anchor tile cannot be retracted due to the difficulty of cutting the unlocking shear pin of the measure pipe string, resulting in pipe string sticking or fracture, improving the safety of the measure pipe string and reducing the construction operation cost.

[0043] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the written specification, claims, and drawings.

[0044] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0045] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0046] Figure 1 is a schematic structural diagram of the anti-sticking anchoring tool in the embodiment of the present invention;

[0047] Figure 2 is a schematic structural diagram of the piston assembly in the embodiment of the present invention;

[0048] Figure 3 is a schematic structural diagram of the support cone in the embodiment of the present invention;

[0049] Figure 4 This is a cross-sectional view of the support cone in the embodiment of the present invention;

[0050] Figure 5 This is a schematic structural diagram of the slips in the embodiment of the present invention;

[0051] Figure 6 In the embodiment of the present invention Figure 5 This is a bottom view schematic diagram of the slips.

[0052] Explanation of reference numerals:

[0053] 1. Upper sub; 2. First central tube; 3. Anti-top lock ring; 4. Outer sleeve; 5. Anti-top lock teeth; 6. Lock block sleeve; 7. Lock block; 8. Support seat; 9. Setting anchor shear pin; 10. Lock ring; 11. Lock teeth; 12. Second central tube; 13. Slips housing; 14. Support cone; 15. First step; 16. Slips; 17. Slips seat; 18. First piston mechanism; 19. Second piston mechanism; 20. Third piston mechanism; 21. Lower sub; 22. First annular space; 23. Second annular space; 24. Third annular space; 25. Fourth annular space; 26. Fifth annular space; 27. Sixth annular space;

[0054] 201. Limit step; 1401. T-shaped keyway; 1402. Conical surface; 1601. Connecting key; 1602. Slip teeth; 1801. First piston seat; 1802. Connecting cylinder; 1803. First liquid inlet hole; 1804. First piston sleeve; 1805. First outer cylinder; 1901. Second piston seat; 1902. Second liquid inlet hole; 1903. Second piston sleeve; 1904. Second outer cylinder; 2001. Third piston seat; 2002. Third liquid inlet hole; 2003. Third piston sleeve; 2004. Third outer cylinder. Detailed implementation manners

[0055] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0056] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0057] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] The inventors of the present application found that the existing anchoring tools mainly rely on the force of the releasing shear pins to counteract the stress effects such as the piston effect, bulging effect, temperature effect, etc. and the upward force of the pipe string. For example, the anchoring packer disclosed in the patent application with the publication number CN113417595A, the magnitude of the shear force of the releasing shear pins in this structure determines the pressure-bearing capacity of the pipe string; if it is set too small, the pipe string will creep and fail under high pressure; if it is set too large, a large enough pulling force is required to cut the releasing shear pins, which is likely to cause the pipe string to get stuck or break, resulting in major repairs.

[0059] Moreover, there is also a situation where the existing anchoring tools cause the measure pipe string to be de-anchored due to temporary pressure relief or internal and external pressure balance, resulting in the creep failure of the packer tool under stress effects such as the temperature effect. In response to this situation: for example, the patent CN210033342U discloses a pipe string anchoring device for an injection well. This anchoring device solves the problems that when the well is shut in, the anchoring force of the hydraulic anchor disappears, the pipe string creeps, and it cannot play a permanent anchoring role, and in high-pressure deep wells and wells with large interlayer pressure differences, the hydraulic anchor is prone to failure due to limited anchoring force. However, it is necessary to rotate the pipe string to change the track to achieve anchoring, and it is difficult to set the anchor in inclined wells or casings with smooth inner walls due to difficult torque transmission or difficult friction commutation; and the upward force of the pipe string and the upward axial force generated by the stress effects such as the bulging effect and temperature effect of the pipe string are offset by the load of the pipe string pressing down. When the upward axial force and the upward force of the pipe string generated by the stress effects such as the bulging effect and temperature effect are too large during high-pressure water injection, fracturing and other measures, it is easy to cause the pipe string to be de-anchored and creep and fail.

[0060] At the same time, when the existing anchoring tools are released from the anchor, the slips are mainly retracted by the restoring force of the spring. For example, the applicant of the present invention has applied for a patent application with the publication number CN115680531A and the patent name of an anti-sticking two-way anchor. However, such a structure has the problem that the spring is prone to lose its elasticity after being repeatedly compressed for a long time, resulting in the inability to retract the anchor slips during the later tubing inspection operation, causing a stuck well accident and turning to major repair.

[0061] In order to solve the problems existing in the prior art, an embodiment of the present invention provides an anti-sticking anchoring tool and its usage method.

[0062] It should be noted that in the embodiment of the present invention, when the two-way anchor is applied, the end connected to the measure string is called the upper end of the two-way anchor, and the end connected to downhole tools such as packers is called the lower end of the two-way anchor.

[0063] The anti-sticking anchoring tool provided by the embodiment of the present invention, referring to Figure 1 and Figure 2 as shown, includes: a central tube, and a thrust assembly, an anchoring mechanism, and a piston assembly that are sequentially sleeved on the central tube;

[0064] The central tube includes: a first central tube 2 and a second central tube 12 sleeved on the first central tube;

[0065] The thrust assembly is sleeved on the first central tube 2 and is fixedly connected to the second central tube 12 at the lower end;

[0066] The anchoring mechanism is sleeved on the second central tube 12;

[0067] The inner holes of the first central tube and the piston assembly form a central flow channel;

[0068] The piston assembly includes at least a first piston mechanism 18. The first piston mechanism 18 includes: a first piston seat 1801, a first piston sleeve 1804, and a first outer cylinder 1805 that are connected; the first piston seat 1801 is fixedly connected to the first outer cylinder 1805, and the first piston sleeve 1804 is arranged in the cavity of the first outer cylinder 1805;

[0069] The lower end of the second central tube 12 is fixedly connected to the first piston sleeve 1804 through a connecting cylinder 1802; the lower end of the anchoring mechanism is fixedly connected to the first piston seat 1801;

[0070] A first annular space is formed between the first piston seat 1801, the second central tube 12, the first piston sleeve 1804 and the first outer cylinder 1805. The first annular space communicates with the central flow path through a first liquid inlet hole 1803 provided on the connecting cylinder 1802. A second annular space is formed between the anchoring mechanism, the second central tube 12 and the first piston seat 1801. A third annular space is formed between the first piston sleeve 1804 and the first outer cylinder 1805. The second annular space and the third annular space communicate with the external environment;

[0071] Under the pressurized state of the central flow path, the hydraulic pressure pushes the first piston sleeve 1804 to drive the second central tube 12 and the thrust assembly to move downward. The thrust assembly pushes the anchoring mechanism to move, so that the anchoring mechanism is anchored to the external casing; and after the anchoring mechanism is anchored to the casing, under the state where the hydraulic pressure acts on the first annular space, the second annular space and the third annular space, the anchoring of the anchoring mechanism is stabilized or strengthened;

[0072] When the first central tube 2 is lifted, it drives the thrust assembly to move upward, so that the anchoring mechanism is disengaged from the casing.

[0073] For the anti-sticking anchoring tool provided by the embodiment of the present invention, under the pressurized state of the central flow path, the first piston seat 1801 squeezes the anchoring mechanism upward, and the first piston unit drives the central tube and the thrust assembly to move downward, so as to push the anchoring mechanism to expand radially and be anchored to the external casing; in the production state such as water injection where the internal pressure is greater than the external pressure, the pressure acts on the first annular space 22, the first piston sleeve 1804 generates a downward force and transmits it to the second central tube connected thereto, and acts on the thrust assembly through the second central tube, which can be used to balance the upward force under the action of the expansion effect and temperature effect of the upper pipe string acting on the first central tube and then acting on the thrust assembly under the condition that the internal pressure is greater than the external pressure. At this time, the first piston seat 1801 generates an upward thrust, and this thrust acts on the anchoring mechanism, which can make the anchoring of the anchoring mechanism to the external casing more reliable; and the anti-sticking anchoring tool of the embodiment of the present invention does not set an anchor release shear pin, and relies on its own structure to offset the acting forces generated by the downhole expansion effect and temperature effect, etc., and can be applied to downhole construction measures such as water injection and fracturing in deep inclined wells; and in the later pipe lifting operation, there is no need to apply an anchor release load, and directly lifting the central tube can drive the thrust assembly to move upward to achieve safe anchor release, eliminating the risk that the anchor tile cannot be retracted due to the difficulty of cutting the anchor release shear pin of the measure pipe string, resulting in pipe string sticking or fracture, improving the safety of the measure pipe string and reducing the construction operation cost.

[0074] Further, the anti-sticking anchoring tool provided by the embodiment of the present invention further includes: an upper sub 1 and a lower sub 21,

[0075] The upper sub 1 is fixedly connected to the first central tube 2, and the lower sub 21 is fixedly connected to the piston assembly;

[0076] A limiting step 201 is provided on the first central tube 2; a first step 15 is provided on the second central tube 12;

[0077] In the state of lifting the first central tube 2, the thrust assembly and the second central tube 12 are driven to move upward through the limiting step 201, and the second central tube 12 drives the anchoring mechanism to move through the first step 15, so that the anchoring mechanism is disengaged from the casing.

[0078] Specifically, the upper joint 1 is fixedly connected and sealed with the first central tube 2 by threads. A sealing ring is provided between the first central tube 2 and the second central tube 12 for sealing. And the outer side of the lower end of the lower joint has pipe threads for fixedly connecting and sealing downhole tools such as oil pipes or packers by threads.

[0079] Furthermore, sealing rings are provided between the first piston seat 1801 and the central tube and the first outer cylinder 1805, and between the first piston sleeve 1804 and the first outer cylinder 1805.

[0080] Optionally, the piston mechanism of the embodiment of the present invention may further include: at least one second piston mechanism 19, and the second piston mechanism 19 includes: a second piston seat 1901, a second piston sleeve 1903 and a second outer cylinder 1904;

[0081] The second piston sleeve 1903 is connected to the first piston sleeve 1804. The second piston seat 1901 is sleeved on the first piston sleeve 1804. And the second outer cylinder 1904 is connected to the first outer cylinder 1805 through the second piston seat 1901. A fourth annular space 25 is formed between the second piston seat 1901 and the first piston sleeve 1804, and the fourth annular space 25 is communicated with the third annular space 24;

[0082] A fifth annular space 26 is formed among the first piston sleeve 1804, the second piston seat 1901 and the second piston sleeve 1903. And a second liquid inlet hole 1902 is provided on the first piston sleeve 1804 to communicate the fifth annular space 26 with the central flow channel;

[0083] A sixth annular space 27 that is annularly communicated with the outside is formed between the second outer cylinder 1904 and the second piston sleeve 1903;

[0084] Correspondingly, in the state where the second piston mechanism 19 is provided with two or more, the liquid inlet holes of the piston mechanisms located below are provided on the piston sleeves of the piston mechanisms located above them.

[0085] Specifically, the first piston seat 1801 is placed outside the lower end of the second central tube 12, and a sealing ring is provided inside it to contact and seal the outside of the lower end of the second central tube 12; the connecting cylinder 1802 is provided with a first liquid inlet hole 1803. The outer side of the upper end of the connecting cylinder 1802 is fixedly connected to the inner side of the lower end of the second central tube 12 by threads, and the outer side of the lower end is fixedly connected to the inner side of the upper end of the first piston sleeve 1804 by threads; the first piston sleeve 1804 is provided with a second liquid inlet hole 1902. Sealing rings are provided on the outer sides of the upper and lower ends of the first piston sleeve 1804 to contact and seal the inner side of the first outer cylinder 1805 and the inner side of the second piston seat 1901 respectively; a sealing ring is provided between the inner side of the upper end of the first outer cylinder 1805 and the outer side of the lower end of the first piston seat 1801 for sealing and they are fixedly connected by threads; the second piston seat 1901 is placed outside the lower end of the first piston sleeve 1804, and the outer side of its upper end is fixedly connected to the inner side of the lower end of the first outer cylinder 1805 by threads; sealing rings are provided on the outer sides of the upper and lower ends of the second piston sleeve 1903 to contact and seal the inner side of the second outer cylinder 1904 and the inner side of the third piston seat 2001 respectively; a sealing ring is provided between the inner side of the upper end of the second outer cylinder 1904 and the outer side of the lower end of the second piston seat 1901 for sealing and they are fixedly connected by threads.

[0086] Optionally, when multiple second piston mechanisms are provided, taking two second piston mechanisms as an example, that is, the anti - jamming anchoring tool provided by the embodiment of the present invention further includes a third piston mechanism 20; the third piston mechanism includes: a third piston seat 2001, a third piston sleeve 2003, and a third outer cylinder 2004. Among them, the third piston seat 2001 is placed outside the lower end of the second piston sleeve 1903, and the outer side of its upper end is fixedly connected to the inner side of the lower end of the second outer cylinder 1904 by threads; sealing rings are provided on the outer sides of the upper and lower ends of the third piston sleeve 2003 to contact and seal the inner side of the third outer cylinder 2004 and the inner side of the lower joint 21 respectively; a sealing ring is provided between the inner side of the upper end of the third outer cylinder 2004 and the outer side of the lower end of the third piston seat 2001 for sealing and they are fixedly connected by threads, and the lower end is fixedly connected to the lower joint 21 by threads. Moreover, the third liquid inlet hole 2002 of the third piston mechanism is arranged on the second piston sleeve 1903.

[0087] It should be noted that in the embodiment of the present invention, when the third annular space 24 or the sixth annular space 27 where the piston mechanism communicates with the external environment, etc., is formed by the outer cylinder, piston sleeve and lower joint of the piston mechanism. Specifically, when the anti - jamming anchoring tool only includes the first piston mechanism, the third annular space 24 is the space formed by the first outer cylinder, the first piston sleeve and the lower joint; when the anti - jamming anchoring tool further includes a second piston mechanism, the sixth annular space 27 is the space formed by the second outer cylinder, the second piston sleeve and the lower joint. When multiple second piston mechanisms are provided, the lowermost annular space is the space formed by the lower joint and the outer cylinder and piston seat of the lowermost piston mechanism.

[0088] Further, air holes are provided on the outer cylinder and / or the piston seat of the piston mechanism provided in the embodiments of the present invention. For example, referring to Figure 1 As shown, air holes are provided on the second piston seat 1901, the third piston seat 2001 and the third outer cylinder 2004, so that the external environment can communicate better with the corresponding annular space, and further the external pressure can act better on the third annular space 24 and the fourth annular space 25.

[0089] In an alternative embodiment, the anchoring mechanism includes: a slip housing 13, a support cone 14, slips 16 and a slip seat 17;

[0090] The slip housing 13 is sleeved on the second central tube 12, an annular cavity is formed between the slip housing 13 and the second central tube 12, and its lower end is threadedly connected to the first piston seat 1801;

[0091] The support cone 14, the slips 16 and the slip seat 17 are sequentially arranged in the annular cavity, and the slip housing 13 is provided with an anchor window for the radial extension of the slips 16;

[0092] The support cone 14 abuts against the thrust assembly, and the slip seat 17 abuts against the first piston seat 1801.

[0093] Further, referring to Figure 3 and Figure 4 As shown, a plurality of T-shaped key grooves 1401 are provided at one end of the support cone 14 close to the slips 16, and the T-shaped key grooves 1401 are of a structure with a wider inner width and a narrower outer width;

[0094] Correspondingly, referring to Figure 5 and Figure 6 As shown, one end of the slips 16 is provided with a connection key 1601 adapted to the T-shaped key grooves 1401, so as to be clamped in the T-shaped key grooves 1401 through the connection key 1601, and the contact surface between the connection key 1601 and the bottom of the T-shaped key grooves 1401 is a conical surface.

[0095] In an alternative embodiment, the thrust assembly includes: an outer sleeve 4, a support seat 8, a lock block sleeve 6;

[0096] The outer sleeve 4 is respectively connected to the upper sub 1 and the slip housing 13, the lock block sleeve 6 is arranged inside the outer sleeve and is connected to the first central tube through a lock block 7;

[0097] The support seat 8 is arranged in the annular cavity formed by the first central tube 2, the outer sleeve 4, the lock block sleeve 6 and the support cone 14. The support seat is connected to the outer sleeve through an anchor shear pin 9, and its lower end is connected to the second central tube 12;

[0098] A locking ring 10 is disposed on the inner wall of the support base 8. Correspondingly, locking teeth 11 adapted to the locking ring 10 are provided on the inner wall of the first central tube 2, so as to limit the upward movement of the support base 8 relative to the first central tube 2 through the cooperation of the locking ring 10 and the locking teeth 11.

[0099] Specifically, the outer sleeve 4 is disposed outside the upper joint 1 and abuts against the upper end of the lock block sleeve 6, and its bottom is fixedly connected to the slip housing 13 by threads. The lock block sleeve 6 is disposed at the bottom of the upper joint 1, outside the first central tube 2, and inside the outer sleeve 4. The upper and lower end faces of the inner side of the described lock block 7 are both inclined planes and are stuck in the card slot of the first central tube 2 and the lock block sleeve 6 to prevent relative movement between the lock block sleeve 6 and the first central tube 2, and its outer side contacts the support base 8. The support base 8 is located in the space surrounded by the first central tube 2, the outer sleeve 4, the lock block sleeve 6, and the support cone 14. The inner side of its lower end is fixedly connected to the outer side of the upper end of the second central tube 12 by threads. The setting anchor shear pin 9 fixes the support base 8 and the outer sleeve 4 to prevent relative movement between the support base 8 and the outer sleeve 4. Only after cutting the setting anchor shear pin 9 can the support base 8 move relative to the outer sleeve 4. The locking ring 10 is placed in the inclined slot inside the support base 8 and is matched with the locking teeth 11 on the first central tube 2. After the two come into contact, they are locked, so that the support base 8 can only move downward relative to the first central tube 2 to the position of the limit step 201 and cannot move upward relative to the first central tube 2, which can avoid the phenomenon that when the hydraulic action disappears, the support base 8 moves back upward, driving the support cone 14 to move back upward, so that the extrusion force of the support cone 14 on the slip 18 weakens or disappears, resulting in the failure of the anchoring of the measure string.

[0100] Furthermore, the support cone 14 is located in the space surrounded by the support base 8, the slip housing 13, the second central tube 12, and the slip 16. Its inner side contacts the outer side of the second central tube 12. The lower end face of the support cone 14 is conical, and a plurality of T-shaped key grooves 1401 with a wider inner width and a narrower outer width corresponding to the slip 16 and a plurality of conical surfaces 1402 are symmetrically arranged on the outer side of the lower end face. The inner side of the slip 16 contacts the outer side of the second central tube 12. The upper end face of the slip is conical and is provided with a connecting key 1601. The connecting key 1601 is an extended part on both sides of the slip 16 body and cooperates with the wider inner groove of the T-shaped key groove 1401 on the support cone 14, so that the upper end face of the slip 16 contacts and is locked with the conical surface 1402 of the support cone 14. The two can slide relative to each other to make the slip 16 radially expand or contract and can prevent the slip 16 from separating from the support cone 14. Among them, the number of the set T-shaped key grooves 1401 corresponds to the number of the slips included in the anchoring tool. The embodiments of the present invention do not make specific limitations on this, and the outer side of the slip 16 is provided with slip teeth 1602 with a certain taper angle for anchoring the inner wall of the casing. Among them, the taper angle (the angle with the vertical plane) of the slip teeth 1602 on the outer side of the slip 16 can be set to 50° - 55°.

[0101] In the anchoring mechanism of the embodiment of the present invention, no spring structure is provided. When anchoring, the support cone 14 squeezes the slip 16, causing the slip 16 to move upward along the abutting surface between the two, thereby realizing the radial expansion of the slip; when unanchoring, due to the cooperation mode of the connecting key 1601 and the T-shaped key groove 1401 between the two, when the support cone moves upward, it will forcibly pull the slip 16 to radially contract and disengage from the inner wall of the casing, releasing the anchor. This structure can better realize the unanchoring of the anchoring structure, avoiding the situation in the existing structure that the spring is prone to lose elasticity after long-term repeated compression, resulting in the inability to retract the anchor tile during the later tubing inspection operation, causing a stuck well accident and turning to major repair.

[0102] Optionally, as shown in Figure 2 the included angle of the bottom abutting surface between the connecting key 1601 and the T-shaped key groove 1401 can be 8° - 12°.

[0103] In an alternative embodiment, as shown in Figure 1 the second central tube 12 is provided with a first step 15, and the support cone 14 is provided with a second step adapted to the first step 15, so as to limit the downward movement of the support cone 14 through the cooperation of the first step 15 and the second step, and drive the support cone 14 to move upward when the second central tube 12 is in the upward movement state;

[0104] The second central tube 12 is further provided with a limiting step 201 to drive the support seat 8 to move upward through the limiting step 201 when the second central tube 12 is in the upward movement state.

[0105] Specifically, the outer radial radius of the lower end of the second central tube 12 is larger than the outer radial radius of the upper end, and the connection between its upper and lower ends forms a first step 15; the inner radial radius of the upper end of the support cone is larger than the inner radial radius of the lower end, and the connection between its upper and lower ends forms a second step. The first step 15 limits the position of the support cone 14 through the second step formed by the difference in the inner radial radii of the upper and lower ends of the support cone 14.

[0106] Optionally, an anti-top lock ring 3 is provided on the inner wall of the outer sleeve 4; correspondingly, an anti-top lock tooth 5 adapted thereto is provided on the outer wall of the upper joint 1 to limit the upward movement of the outer sleeve 4 relative to the central tube through the cooperation of the anti-top lock ring 3 and the anti-top lock tooth 5.

[0107] Specifically, the anti-top-lock teeth 5 are arranged on the outer side of the bottom of the first central tube 2, and the anti-top-lock ring 3 is arranged in the inner inclined groove at the upper end of the outer sleeve 4, which is matched with the anti-top-lock teeth 5 on the upper joint 1. When the first central tube moves upward, the two are locked after contact, so that the outer sleeve 4 can only move downward relative to the upper joint 1 and cannot move upward relative to the upper joint 1. When lifting the measure string after releasing the anchor, it can prevent the structure connected to the lower part of the outer sleeve from moving upward under the inertia of the measure string during the process of changing the elevator, resulting in relative movement between the slip 16 and the support cone 14 and then radially expanding along the contact cone surface 1402 and getting stuck on the inner wall of the casing, causing the measure string to get stuck during lifting and lowering, affecting the efficiency of changing the elevator and removing a single joint.

[0108] Taking the piston assembly including a first piston mechanism and two second piston mechanisms as an example, the process and effect of the anti-sticking and anchoring tool provided by the embodiment of the present invention during downhole operation are exemplarily described as follows:

[0109] In specific implementation, the anti-sticking and anchoring tool supporting the measure string for layered water injection, fracturing, etc. is arranged above downhole tools such as packers.

[0110] During the process of lowering the measure string, the upper end of the upper joint 1 is threadedly fixed to connect the tubing, and the lower end of the lower joint 21 is threadedly fixed to connect the string with downhole tools such as packers. Since the upper joint 1 is threadedly fixed to connect the first central tube 2, and the lock block 7 is stuck in the card slot of the first central tube 2 and the lock block sleeve 6, the lock block sleeve 6 is fixed on the first central tube 2. The outer sleeve 4 is suspended on the lock block sleeve 6. The outer sleeve 4 fixes the support seat 8 through the setting anchor shear pin 9 and is threadedly fixed to connect with the slip housing 13. The support seat 8 is threadedly fixed to connect with the second central tube 12. The first step 15 on the second central tube 12 restricts the movement of the support cone 14. Therefore, the upper joint 1, the first central tube 2, the outer sleeve 4, the lock block sleeve 6, the support seat 8, the second central tube 12, the slip housing 13, and the support cone 14 remain relatively fixed; and because the upper end surface of the slip 16 contacts and locks with the cone surface 1402 of the support cone 14, the slip 16 and the support cone 14 are relatively fixed and are restricted within the slip housing 13 to ensure the safe lowering of the measure string; and when the measure string collides with the casing collar, etc., causing the lower joint 21 to be impacted, this impact force is sequentially transmitted through the lower joint 21, the third outer cylinder 2004, the third piston seat 2001, the second outer cylinder 1904, the second piston seat 1901, the first outer cylinder 1805, the first piston seat 1801, the slip housing 13, and the outer sleeve 4 to the upper joint 1 and the tubing above it, protecting the setting anchor shear pin 9 from fatigue shear under the action of repeated alternating loads.

[0111] After the measure string is lowered to the designed position, it is lifted by a certain height (such as 1 meter and half a meter), and then the pressure is gradually increased from the tubing. The hydraulic pressure enters through the first liquid inlet hole 1803, the second liquid inlet hole 1902, and the third liquid inlet hole 2002, and acts on the contact surfaces between the first piston seat 1801 and the first piston sleeve 1804, the second piston seat 1901 and the second piston sleeve 1903, and the third piston seat 2001 and the third piston sleeve 2003. The first piston sleeve 1804, the second piston sleeve 1903, and the third piston sleeve 2003 generate a downward thrust under the action of the hydraulic pressure and act on the setting anchor shear pin 9 through the second central tube 12 and the support seat 8. Moreover, the higher the hydraulic pressure, the greater the downward thrust generated. When the hydraulic pressure rises to a certain value, the downward thrust generated cuts off the setting anchor shear pin 9 and then pushes the support seat 8, the second central tube 12, the first piston sleeve 1804, the second piston sleeve 1903, and the third piston sleeve 2003 to move downward, pushing the support cone 14 to move downward. After the support seat 8 moves downward, the locking block 7 disengages from the slot of the locking block sleeve 6 and falls into the space vacated by the support seat 8, so that the locking block sleeve 6 is disengaged from the fixation with the first central tube 2. Since the first piston seat 1801, the second piston seat 1901, and the third piston seat 2001 generate an upward thrust under the action of the hydraulic pressure and act on the slip housing 13 and the slip seat 17, providing an upward supporting force for the slip seat 17 and the slip housing, the downward movement of the slips 16 is restricted. Under the push of the support cone 14, the slips 16 radially expand along the contact cone surface 1402 and are stuck on the inner wall of the casing, realizing the anchoring of the measure string. At this time, after the support seat 8 moves downward, the locking ring 10 contacts and locks with the locking teeth 11 on the first central tube 2, preventing the support seat 8 from moving upward relative to the first central tube 2, which may cause the support cone 14 to move upward, and then drive the slips 16 to radially contract and release the anchoring phenomenon through the mutual cooperation of the T-shaped key groove 1401 and the connecting key 1601. The lifted part of the measure string is pressed back to release part of the string load. Since the measure string has been anchored, the measure string cannot move downward. The released string load is pressed on the upper joint 1 and the first central tube 2, and then through the locked locking ring 10 and the locking teeth 11, it is pressed on the support seat 8 and the upper support cone 14, and finally pressed on the slips 16 and the inner wall of the casing, so that the slips 16 always maintain the state of being radially expanded and stuck on the inner wall of the casing, preventing the phenomenon that when the external pressure is higher than the internal pressure due to measures such as backwashing the well, the first piston sleeve 1804, the second piston sleeve 1903, and the third piston sleeve 2003 generate an upward thrust to push the support cone 14 to move upward, and then drive the slips 16 to radially contract and release the anchoring.

[0112] During measures such as separate layer water injection and fracturing production, the measure string is subjected to the action of internal and external pressure differences and the upper and lower pressure differences of the lower packer tool. Since the anti-sticking anchoring tool anchors the measure string on the inner wall of the casing and restricts the creep of the measure string, the measure string is stressed due to expansion effect, piston effect, etc. under the internal and external, upper and lower pressure differences.

[0113] When the internal pressure is greater than the external pressure, an expansion effect that shortens the pipe string and an upward pulling force are generated. This upward pulling force acts on the first central pipe 2 through the work string and the upper joint 1, and then acts on the support seat 8 through the limiting step 201. Under the hydraulic action where the internal pressure is greater than the external pressure, the first piston sleeve 1804, the second piston sleeve 1903, and the third piston sleeve 2003 all generate downward piston thrusts and jointly act on the support seat 8 through the second central pipe 12, which is sufficient to offset the upward pulling force generated by the expansion effect. At the same time, under the hydraulic action where the internal pressure is greater than the external pressure, the first piston seat 1801, the second piston seat 1901, and the third piston seat 2001 all generate upward piston thrusts and jointly act on the slip housing 13 and the slip seat 17, and then are transmitted to the slips 16 and the inner wall of the casing, avoiding the creep of the work string under force and ensuring the production safety of the work string.

[0114] When the internal pressure is less than the external pressure, a reverse expansion effect that elongates the pipe string and a downward pressure are generated. This downward pressure, together with the part of the pipe string load released by the upward movement of the work string, acts on the first central pipe 2 through the upper joint 1, and then is pressed onto the support seat 8 through the locked lock ring 10 and lock teeth 11 to offset the upward piston thrust generated by the first piston sleeve 1804, the second piston sleeve 1903, and the third piston sleeve 2003 under the hydraulic action where the internal pressure is less than the external pressure. At the same time, under the hydraulic action where the internal pressure is less than the external pressure, the first piston seat 1801, the second piston seat 1901, and the third piston seat 2001 generate upward piston thrusts and jointly act on the slip housing 13, and then are transmitted to the slips 16 and the inner wall of the casing, avoiding the creep of the work string under force and ensuring the production safety of the work string.

[0115] When the lower packer tool causes the work string to generate upward or downward piston thrusts due to the effect under the differential pressure between the upper and lower parts, this piston thrust acts on the lower joint 21 through the work string, and then is transmitted to the slips 16 and the inner wall of the casing through the third outer cylinder 2004, the third piston seat 2001, the second outer cylinder 1904, the second piston seat 1901, the first outer cylinder 1805, the first piston seat 1801, and the slip housing 13, avoiding the creep of the work string under force and ensuring the production safety of the work string.

[0116] During workover operations, the pressure of the work string is relieved to balance the pressure inside and outside the string. The first piston sleeve 1804, the second piston sleeve 1903, the third piston sleeve 2003, the first piston seat 1801, the second piston seat 1901, and the third piston seat 2001 are not stressed under the balanced internal and external pressure. When the work string is lifted, the upper joint 1 and the first central tube 2 are lifted upward. The upper limit step 201 of the first central tube 2 drives the support seat 8 and the second central tube 12 to move upward. The first step 15 on the second central tube 12 drives the support cone 14, the connecting cylinder 1802, the first piston sleeve 1804, the second piston sleeve 1903, and the third piston sleeve 2003 to move upward. The support cone 14 cooperates with the connecting key 1601 through the T-shaped keyway 1401 to forcibly pull the slips 16 to radially contract and disengage from the inner wall of the casing, releasing the anchoring and preventing the work string from getting stuck. Continuing to lift the work string, the support seat 8 pushes the lock block sleeve 6 upward, the lock block sleeve 6 pushes the outer sleeve 4 upward, and the outer sleeve 4 successively pulls the slip housing 13, the slip seat 17, the first piston seat 1801, the first outer tube 1805, the second piston seat 1901, the second outer tube 1904, the third piston seat 2001, the third outer tube 2004, and the lower joint 21 upward, finally pulling out the entire work string.

[0117] Optionally, in high-pressure water injection or fracturing operations, due to different production construction pressures, the work string is subjected to different magnitudes of force due to expansion effects, piston effects, etc. Considering the force conditions of the work string comprehensively, the number of second piston mechanisms can be increased or decreased according to actual needs. The embodiments of the present invention do not specifically limit the number of second piston mechanisms included in the anchoring tool.

[0118] The anti-sticking anchoring tool provided by the embodiments of the present invention can use the piston force generated by the piston assembly to push the support cone to expand the slips and anchor the work string tightly, and offset the acting forces generated by the work string due to expansion effects, piston effects, etc., adapting to different production construction pressures. The greater the production construction pressure, the greater the downward piston thrust generated by the first piston seat, the second piston seat, and the third piston seat. The downward piston thrust generated by the first piston seat, the second piston seat, and the third piston seat acts on the support seat through the second central tube together to offset the upward pulling force generated by the work string due to expansion effects, etc. The upward or downward force of the work string and the upward piston thrust generated by the first piston seat, the second piston seat, and the third piston seat act on the slip housing and the slip seat together, and then are transmitted to the slips and the inner wall of the casing, strengthening the anchoring of the anchoring mechanism, improving the anchoring reliability of the anchoring mechanism, avoiding the situation of work string anchoring failure and force-induced creep, and ensuring the production safety of the work string.

[0119] Moreover, the anti-sticking anchoring tool provided by the embodiment of the present invention has no anchor-release shear pin structure. During the later tubing lifting operation, there is no need to apply an anchor-release load. Simply lifting the upper joint and the first central tube can achieve safe anchor release, eliminating the risk that the anchor tile cannot be retracted due to the difficulty of cutting the anchor-release shear pin in the measure string, resulting in pipe sticking or fracture of the pipe string, improving the safety of the measure string, reducing the construction operation cost, and can be widely used in measures such as water injection and fracturing in deep inclined wells.

[0120] Based on the same inventive concept, the embodiment of the present invention also provides a usage method of the above anti-sticking anchoring tool, including:

[0121] Controlling the pressure increase inside the central tube, the pressure acts on the first annular space, the first piston seat squeezes the anchoring mechanism upward, and the first piston unit drives the central tube and the thrust assembly to move downward, so as to push the anchoring mechanism to expand radially and anchor with the external casing;

[0122] Controlling the pressure relief inside the central tube, lifting the central tube, driving the thrust assembly to move upward, and releasing the anchoring of the anchoring mechanism with the casing.

[0123] Regarding the usage method of the anti-sticking anchoring tool in the above embodiment, its specific usage method has been described in detail in the embodiment related to the anti-sticking anchoring tool, and will not be elaborated here.

[0124] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the protection scope of the present disclosure. The appended method claims present the elements of various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy.

[0125] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than those clearly stated in each claim. On the contrary, as reflected in the appended claims, the present invention is in a state with fewer features than all the features of the disclosed single embodiment. Therefore, the appended claims are hereby clearly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of the present invention.

[0126] The foregoing description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but those of ordinary skill in the art should recognize that the various embodiments can be further combined and arranged. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications, and variations that fall within the scope of the appended claims. In addition, with respect to the term "comprising" as used in the specification or claims, that term is inclusive in a manner similar to the term "including," as that term is interpreted when used as a transitional word in a claim. Further, any use of the term "or" in the claims or specification is to be meant "non-exclusive or."

Claims

1. A stuck-preventing anchoring tool, comprising a central tube, characterized in that, It further includes a thrust assembly, an anchoring mechanism, and a piston assembly that are sequentially sleeved on the central tube; The central tube includes: a first central tube (2) and a second central tube (12) sleeved on the first central tube; The thrust assembly is sleeved on the first central tube (2) and is fixedly connected to the second central tube (12) at the lower end; The anchoring mechanism is sleeved on the second central tube (12); The inner holes of the first central tube and the piston assembly form a central flow channel; The piston assembly at least includes a first piston mechanism (18), and the first piston mechanism (18) includes: a first piston seat (1801), a first piston sleeve (1804), and a first outer cylinder (1805) that are connected; the first piston seat (1801) is fixedly connected to the first outer cylinder (1805), and the first piston sleeve (1804) is arranged in the cavity of the first outer cylinder (1805); The lower end of the second central tube (12) is fixedly connected to the first piston sleeve (1804) through a connecting cylinder (1802); the lower end of the anchoring mechanism is fixedly connected to the first piston seat (1801); A first annular space is formed between the first piston seat (1801), the second central tube (12), the first piston sleeve (1804), and the first outer cylinder (1805). The first annular space is communicated with the central flow channel through a first liquid inlet hole (1803) arranged on the connecting cylinder (1802). A second annular space is formed between the anchoring mechanism, the second central tube (12), and the first piston seat (1801). A third annular space is formed between the first piston sleeve (1804) and the first outer cylinder (1805). The second annular space and the third annular space are communicated with the external environment; Under the pressurized state of the central flow channel, the hydraulic pressure pushes the first piston sleeve (1804) to drive the second central tube (12) and the thrust assembly to move downward. The thrust assembly pushes the anchoring mechanism to move, so that the anchoring mechanism is anchored to the external casing; and after the anchoring mechanism is anchored to the casing, under the state where the hydraulic pressure acts on the first annular space, the second annular space, and the third annular space, the anchoring of the anchoring mechanism is stabilized or strengthened; When the first central tube (2) is lifted, it drives the thrust assembly to move upward, so that the anchoring mechanism is disengaged from the casing.

2. The stuck-preventing anchoring tool according to claim 1, characterized in that, Sealing rings are arranged between the first piston seat and the second central tube (12) and the first outer cylinder, and between the first piston sleeve and the first outer cylinder.

3. The stuck-preventing anchoring tool according to claim 2, characterized in that, The piston assembly further includes: at least one second piston mechanism (19), and the second piston mechanism (19) includes: a second piston seat (1901), a second piston sleeve (1903), and a second outer cylinder (1904); The second piston sleeve (1903) is fixedly connected to the first piston sleeve (1804). The second piston seat (1901) is sleeved on the first piston sleeve (1804), and the second outer cylinder (1904) is fixedly connected to the first outer cylinder (1805) through the second piston seat (1901). A fourth annular space is formed between the second piston seat (1901) and the first piston sleeve (1804), and the fourth annular space communicates with the third annular space; A fifth annular space is formed among the first piston sleeve (1804), the second piston seat (1901) and the second piston sleeve (1903), and a second liquid inlet hole (1902) is arranged on the first piston sleeve (1804) to communicate the fifth annular space with the central flow channel; A sixth annular space communicating with the external environment is formed between the second outer cylinder (1904) and the second piston sleeve (1903); Correspondingly, when the second piston mechanism is in a state of being two or more, the liquid inlet hole of the piston mechanism located below is arranged on the piston sleeve of the piston mechanism located above it.

4. The stuck-preventing anchoring tool according to claim 3, characterized in that, Air holes are arranged on the outer cylinder and / or the piston seat of the piston assembly.

5. The stuck-preventing anchoring tool according to any one of claims 1-4, characterized in that, Further included are: an upper joint (1) and a lower joint (21); The upper joint (1) is fixedly connected to the first central tube (2), and the lower joint (21) is fixedly connected to the piston assembly; A limiting step (201) is arranged on the first central tube (2); a first step (15) is arranged on the second central tube (12); When the first central tube (2) is lifted, the thrust assembly and the second central tube (12) are driven to move upward through the limiting step (201), and the second central tube (12) drives the anchoring mechanism to move through the first step (15) so that the anchoring mechanism is disengaged from the casing.

6. The stuck-preventing anchoring tool according to claim 5, characterized in that, The anchoring mechanism includes: a slip housing (13), a support cone (14), slips (16) and a slip seat (17); The slip housing (13) is sleeved on the second central tube (12), and an annular cavity is formed between the slip housing (13) and the second central tube (12), and its lower end is fixedly connected to the first piston seat (1801); The support cone (14), the slips (16) and the slip seat (17) are sequentially arranged in the annular cavity, and an anchor window for the radial protrusion of the slips (16) is formed on the slip housing (13); The support cone (14) abuts against the thrust assembly, and the slip seat (17) abuts against the first piston seat (1801).

7. The stuck-preventing anchoring tool according to claim 6, characterized in that, A plurality of T-shaped key grooves (1401) are arranged at one end of the support cone (14) close to the slips (16), Correspondingly, one end of the slips (16) is provided with a connecting key (1601) adapted to the T-shaped key grooves (1401) so as to be clamped in the T-shaped key grooves (1401) through the connecting key, and the contact surface of the connecting key and the bottom of the T-shaped key grooves (1401) is a conical surface.

8. The stuck-preventing anchoring tool according to claim 7, characterized in that, The cone angle of the conical surface is: 8° - 12°.

9. The stuck-preventing anchoring tool according to claim 5, characterized in that, The thrust assembly includes: an outer sleeve (4), a support base (8), and a lock block sleeve (6); The outer sleeve (4) is fixedly connected to the upper sub (1) and the slip housing (13) respectively. The lock block sleeve (6) is arranged inside the outer sleeve (4) and is connected to the first central tube (2) through a lock block (7); The support base (8) is arranged in an annular cavity formed by the first central tube (2), the outer sleeve (4), the lock block sleeve (6), and the support cone (14). The support base (8) is connected to the outer sleeve (4) through a setting anchor shear pin (9), and its lower end is connected to the second central tube (12); A lock ring (10) is arranged on the inner wall of the support base (8). Correspondingly, lock teeth (11) adapted to the lock ring (10) are arranged on the inner wall of the first central tube (2) to limit the upward movement of the support base (8) relative to the first central tube (2) through the cooperation of the lock ring (10) and the lock teeth (11).

10. The anti-sticking anchoring tool according to claim 9, wherein An anti - top lock ring (3) is arranged on the inner wall of the outer sleeve (4); Correspondingly, anti - top lock teeth (5) adapted thereto are arranged on the outer wall of the upper sub (1) to limit the upward movement of the outer sleeve (4) relative to the central tube through the cooperation of the anti - top lock ring (3) and the anti - top lock teeth (5).

11. The anti-sticking anchoring tool according to claim 9, wherein A second step adapted to the first step (15) is arranged on the support cone (14) to limit the downward movement of the support cone (14) through the cooperation of the first step (15) and the second step, and drive the support cone (14) to move upward when the second central tube (12) is in an upward movement state.

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