Self-locking hydraulic anchor

Abstract

The utility model belongs to the technical field of oil and gas field downhole operation tools, and discloses a self-locking type hydraulic anchor which cannot generate irreversible damage to a sleeve along with pressure increase. A water injection hole is formed in the lower part of the middle core rod; the middle core rod is sleeved with the hydraulic anchor shell, an annular groove is formed in the inner wall of the hydraulic anchor shell so that an annular cavity can be formed between the hydraulic anchor shell and the middle core rod, a plurality of containing grooves are formed in the peripheral wall of the hydraulic anchor shell, and runner holes are formed in the containing grooves; and an anchoring assembly. The self-locking hydraulic anchor has an initial state: the water injection hole is not communicated with the annular cavity, and the anchoring assembly is positioned in the accommodating groove; in the pressurization state, the middle core rod is lifted upwards to enable the water injection hole to be communicated with the annular cavity, so that fluid sequentially passes through the center flow channel, the water injection hole, the annular cavity and the flow channel hole to provide thrust for the anchoring assembly to protrude outwards; and in the anchoring state, the middle core rod is pressed downwards to disconnect the water injection hole from the annular cavity, so that the fluid pressure in the annular cavity is kept unchanged, and anchoring of the anchoring assembly and the external sleeve is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of downhole working tools in oil and gas fields, in particular to a self-locking hydraulic anchor. Background Art

[0002] Hydraulic anchors are usually used to anchor the pipes in the process of water injection, hydraulic fracturing, hydraulic cutting, and undercutting in the process of downhole operations such as oil and gas field development, so as to avoid axial displacement of downhole tools during the operation. When the hydraulic anchor and the hydraulic undercut device form a pipe string for hydraulic undercutting, the conventional baffle-type and supporting-type hydraulic anchors will continue to pressurize the casing after anchoring it, and when the undercutting operation is continued, the anchor claws will continue to extend outward as the pressure increases, which will cause irreversible damage to the casing. Utility Model Content

[0003] The utility model aims to provide a self-locking hydraulic anchor, which avoids the problem that the anchor claws of the existing hydraulic anchor continue to eat into the casing as the hydraulic pressure increases, thereby causing irreversible damage to the casing.

[0004] According to the utility model, the self-locking hydraulic anchor comprises: a core rod, the inner center of the core rod has a central flow channel penetrating therethrough, and the lower part of the core rod is also formed with a water injection hole connected to the central flow channel; a hydraulic anchor shell sleeved outside the core rod, the inner wall of the hydraulic anchor shell is formed with an annular groove to form an annular cavity between the hydraulic anchor shell and the core rod, and the outer peripheral wall of the hydraulic anchor shell is axially provided with a plurality of receiving grooves, and the receiving grooves are also formed with flow channel holes connected to the annular cavity; and an anchor assembly located in the receiving groove, wherein the self-locking hydraulic anchor assembly is provided ... The lock-type hydraulic anchor has an initial state: the water injection hole is not connected to the annular cavity, and the anchor assembly is located in the receiving groove; a pressurized state: the core rod is lifted to connect the water injection hole with the annular cavity, so that the fluid passes through the central flow channel, the water injection hole, the annular cavity and the flow channel hole in sequence to provide thrust to the anchor assembly in the receiving groove, so that the anchor assembly protrudes to the outside of the hydraulic anchor shell; and an anchored state: the core rod is pressed down to disconnect the connection between the water injection hole and the annular cavity to keep the fluid pressure in the annular cavity unchanged, thereby realizing the anchoring of the anchor assembly and the external casing.

[0005] Furthermore, a lifting nut is fixedly connected to the outer peripheral wall of the lower end of the core rod, and a step is formed on the inner peripheral wall of the lower part of the hydraulic anchor shell for stopping the lifting nut when lifting the core rod.

[0006] Furthermore, the accommodating groove includes a straight groove formed on the outer surface of the hydraulic anchor shell and a cylindrical hole connected to the straight groove, and the anchor assembly includes an anchor claw located in the cylindrical hole, an elastic member elastically abutting against the anchor claw, and a pressure plate, wherein the pressure plate is located in the straight groove and is used to pre-compress the anchor claw and install it in the cylindrical hole, wherein, under the pressurized state: the fluid pushes the anchor claw to overcome the elastic force of the elastic member and radially extend out of the cylindrical hole.

[0007] Further, the fluke is formed in a plunger shape, an anchoring tooth is formed on the end surface of the fluke, a groove is also formed on the end surface of the fluke, and the elastic member abuts against the groove.

[0008] Furthermore, the elastic member is a bow-shaped leaf spring, which includes a connecting portion that fits with the hydraulic anchor shell and a bent portion connected to both ends of the connecting portion, the bent portion is bent toward the anchor claw, the two bent portions are respectively located in adjacent cylindrical holes and elastically abut against the anchor claw, and the axial length of the pressure plate is greater than the spacing between adjacent cylindrical holes.

[0009] Furthermore, the curved portion includes an arc plate connected to the connecting portion and a fixing plate connected to the arc plate, the arc plate is located in the cylindrical hole and elastically abuts against the anchor claw, and the fixing plate and the connecting portion are both fixed to the hydraulic anchor shell by pins.

[0010] Furthermore, a first sealing ring is provided between the fluke and the cylindrical hole.

[0011] Furthermore, second sealing rings are provided on the upper and lower sides of the core rod located at the water injection hole.

[0012] Furthermore, a dust ring is provided between the upper end of the core rod and the hydraulic anchor housing.

[0013] Furthermore, the core rod is spline-connected to the hydraulic anchor housing.

[0014] Compared with the prior art, the self-locking hydraulic anchor of the utility model can achieve the reliable effect of maintaining anchoring after the pressure in the oil pipe drops by enclosing the high-pressure liquid (or hydraulic oil) in the annular cavity; when the hydraulic anchor is unsealed, the high-pressure liquid in the annular cavity can be removed by lifting the center core rod to achieve unsealing. At the same time, the lower end of the center tube of the self-locking hydraulic anchor of the utility model is provided with a water injection hole, and the water injection hole is connected with the anchor claw by lifting the center core rod and high-pressure liquid is introduced. After anchoring is achieved, the pipe column is lowered and the water injection hole is closed to achieve the self-locking function of the anchor claw. There are fewer parts involved, the working method is simple and reliable, and it can be reused many times. In addition, since the self-locking hydraulic anchor of the utility model uses the self-locking mechanism to keep the anchor claw in the anchor state after being stuck, it is not affected by the creep of the pipe column and the change of the water injection pressure, so the sealing ability of the self-locking hydraulic anchor is enhanced, and the problems of pressure reversal anchor failure and casing damage are solved. In addition, the provision of the first sealing ring, the second sealing ring and the dustproof ring also avoids problems such as corrosion and scaling caused by the injection of water, thereby improving the reliability of the card release. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a self-locking hydraulic anchor according to an embodiment of the utility model;

[0016] Figure 2 for Figure 1The schematic cross-sectional view along the AA direction is shown;

[0017] Figure 3 for Figure 1 An enlarged exploded view of point B is shown. DETAILED DESCRIPTION

[0018] In order to better understand the purpose, structure and function of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings.

[0019] Figure 1 The structure of the self-locking hydraulic anchor 100 according to an embodiment of the utility model is shown. Figure 1 As shown, the self-locking hydraulic anchor 100 may include: a core rod 1, the inner center of the core rod 1 has a central flow channel 16 running through it, and the lower part of the core rod 1 is also formed with a water injection hole 14 connected to the central flow channel 16; a hydraulic anchor shell 2 sleeved outside the core rod 1, the inner wall of the hydraulic anchor shell 2 is formed with an annular groove to form an annular cavity 10 between the hydraulic anchor shell 2 and the core rod 1, and the outer peripheral wall of the hydraulic anchor shell 2 is axially provided with a plurality of receiving grooves 30, and the receiving grooves 30 are also formed with flow channel holes 11 connected to the annular cavity 10; and an anchor assembly 20 (such as Figure 3 As shown), the self-locking hydraulic anchor 100 has an initial state: the water injection hole 14 is not connected to the annular cavity 10, and the anchor assembly 20 is located in the receiving groove 30; a pressurized state: the core rod 1 is lifted to connect the water injection hole 14 with the annular cavity 10, so that the fluid passes through the central flow channel 16, the water injection hole 14, the annular cavity 10 and the flow channel hole 11 in sequence to provide thrust to the anchor assembly 20 in the receiving groove 30, so that the anchor assembly 20 protrudes to the outside of the hydraulic anchor shell 2; and an anchored state: the core rod 1 is pressed down to disconnect the water injection hole 14 from the annular cavity 10, so as to keep the fluid pressure in the annular cavity 10 unchanged, thereby realizing the anchoring of the anchor assembly 20 and the external casing.

[0020] like Figure 1 As shown, when the self-locking hydraulic anchor 100 of the embodiment of the utility model is working, the water injection hole 14 is connected with the annular cavity 10 by lifting the central core rod 1, and the pressurized fluid entering through the central flow channel 16 sequentially passes through the water injection hole 14, the annular cavity 10 and the flow channel hole 11 to provide thrust to the anchor assembly 20 in the accommodating groove 30, so that the anchor assembly 20 protrudes to the outside of the hydraulic anchor shell 2; when the anchor assembly 20 is anchored to the external casing, the central core rod 1 is pressed down to disconnect the connection between the water injection hole 14 and the annular cavity 10 to keep the fluid pressure in the annular cavity 10 unchanged, and the constant closed pressure provides a constant and continuous pressure for the anchor assembly 20, which is not affected by the pressure change during subsequent operations. Therefore, the anchor assembly 20 will not continue to extend outward when the pressure changes in subsequent operations and cause irreversible damage to the casing.

[0021] In such Figure 1 In the preferred embodiment shown, a lifting nut 12 is fixedly connected to the outer peripheral wall of the lower end of the core rod 1, and a step 19 is formed on the inner peripheral wall of the lower part of the hydraulic anchor housing 2 for stopping the lifting nut 12 when the core rod 1 is lifted. Preferably, the lifting nut 12 can be threadedly connected to the core rod 1. The contact stop between the lifting nut 12 and the step 19 can be used as a trigger point for the water injection hole 14 to communicate with the annular cavity 10, and can be used to prevent the core rod 1 from slipping out of the hydraulic anchor housing 2.

[0022] Preferably, when the lifting nut 12 abuts against the step 19 , the water injection hole 14 is just connected with the annular cavity 10 .

[0023] In such Figure 1 and Figure 3 In the preferred embodiment shown, the accommodating groove 30 may include a straight groove 15 formed on the outer surface of the hydraulic anchor shell 2 and a cylindrical hole 9 connected to the straight groove 15, and the anchor assembly 20 may include a fluke 6 located in the cylindrical hole 9, an elastic member 5 elastically abutting against the fluke 6, and a pressure plate 4, wherein the pressure plate 4 is located in the straight groove 15 and is used to pre-compress the fluke 6 and install it in the cylindrical hole 9, wherein, under the pressurized state: the fluid pushes the fluke 6 to overcome the elastic force of the elastic member 5 and radially extend out of the cylindrical hole 9.

[0024] Furthermore, the cat claw 6 can be formed into a plunger shape, an anchoring tooth 61 is formed on the end surface of the anchor claw 6, a groove 7 is also formed on the end surface of the anchor claw 6, and the elastic member abuts against the groove 7.

[0025] In such Figure 3 In the preferred embodiment shown, the Figure 1 As shown, the elastic member 5 may be a bow-shaped leaf spring, which includes a connecting portion 51 that fits the hydraulic anchor housing 2 and a bent portion 52 connected to both ends of the connecting portion 51, the bent portion 52 is bent toward the fluke 6, the two bent portions 52 are respectively located in adjacent cylindrical holes 9 and elastically abut against the fluke 6, and the axial length of the pressure plate 4 is preferably greater than the spacing between adjacent cylindrical holes 9. In this embodiment, the structural setting of the bow-shaped leaf spring enables the pre-compression of two flukes 6 to be achieved simultaneously by using one bow-shaped leaf spring, and the axial length of the pressure plate 4 is greater than the spacing between adjacent cylindrical holes 9, so that the bow-shaped leaf spring can be fixed more stably.

[0026] Furthermore, if Figure 3 As shown, the curved portion 52 includes an arc plate connected to the connecting portion and a fixing plate 53 connected to the arc plate. The arc plate is located in the cylindrical hole 9 and elastically abuts against the anchor claw 6. The fixing plate 53 and the connecting portion 51 are both fixed to the hydraulic anchor shell 2 by pins 3 to further achieve a more stable fixation of the bow leaf spring.

[0027] In such Figure 3 In the preferred embodiment shown, a first sealing ring 8 may be provided between the fluke 6 and the cylindrical hole 9 , and the first sealing ring 8 may prevent the fluid from flowing out of the cylindrical hole 9 .

[0028] In such Figure 1 In the preferred embodiment shown, the core rod 1 is provided with second sealing rings 17 on both sides of the water injection hole 14. After the connection between the water injection hole 14 and the annular cavity 10 is disconnected, the fluid in the annular cavity 10 is sealed by the second sealing ring 17 to keep the liquid pressure in the annular cavity 10 unchanged.

[0029] Furthermore, if Figure 1 As shown, a dust ring 18 may be provided between the upper end of the core rod 1 and the hydraulic anchor housing 2 to prevent impurities from entering between the core rod 1 and the hydraulic anchor housing 2 .

[0030] According to the utility model, in Figure 2 In the preferred embodiment shown, the core rod 1 and the hydraulic anchor housing 2 may be connected via a spline structure, so as to achieve position limiting between the core rod 1 and the hydraulic anchor housing 2 and transmit circumferential torque.

[0031] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by technicians in the field to which the utility model belongs.

[0032] In the description of this application, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it; although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model, and they should all be included in the scope of the claims and description of the utility model. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The utility model is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A self-locking hydraulic anchor, characterized in that: include: The core rod has a central flow channel extending through the center of the core rod, and a water injection hole connected to the central flow channel is formed at the lower part of the core rod. A hydraulic anchor housing is sleeved outside the core rod, an annular groove is formed on the inner wall of the hydraulic anchor housing to form an annular cavity between the hydraulic anchor housing and the core rod, a plurality of receiving grooves are axially arranged on the outer peripheral wall of the hydraulic anchor housing, and a flow channel hole connected to the annular cavity is also formed in the receiving groove, and an anchoring assembly located in the receiving groove, Among them, the self-locking hydraulic anchor has an initial state: the water injection hole is not connected to the annular cavity, and the anchor assembly is located in the receiving groove; a pressurized state: the core rod is lifted to connect the water injection hole with the annular cavity, so that the fluid passes through the central flow channel, the water injection hole, the annular cavity and the flow channel hole in sequence to provide thrust to the anchor assembly in the receiving groove, so that the anchor assembly protrudes to the outside of the hydraulic anchor shell; and an anchored state: the core rod is pressed down to disconnect the connection between the water injection hole and the annular cavity to keep the fluid pressure in the annular cavity unchanged, thereby realizing the anchoring of the anchor assembly and the external casing.

2. The self-locking hydraulic anchor according to claim 1, characterized in that: A lifting nut is fixedly connected to the outer peripheral wall of the lower end of the central rod, and a step for stopping the lifting nut when lifting the central rod is formed on the inner peripheral wall of the lower part of the hydraulic anchor shell.

3. The self-locking hydraulic anchor according to claim 1 or 2, characterized in that: The accommodating groove includes a straight groove formed on the outer surface of the hydraulic anchor shell and a cylindrical hole connected to the straight groove. The anchor assembly includes an anchor claw located in the cylindrical hole, an elastic member elastically abutting against the anchor claw, and a pressure plate. The pressure plate is located in the straight groove and is used to pre-compress the anchor claw and install it in the cylindrical hole. In the pressurized state, the fluid pushes the anchor claw to overcome the elastic force of the elastic member and radially extend out of the cylindrical hole.

4. The self-locking hydraulic anchor according to claim 3, characterized in that: The fluke is formed in a plunger shape, an anchoring tooth is formed on the end surface of the fluke, a groove is also formed on the end surface of the fluke, and the elastic member abuts against the groove.

5. The self-locking hydraulic anchor according to claim 3, characterized in that: The elastic member is a bow-shaped leaf spring, which includes a connecting portion that fits the hydraulic anchor shell and a bent portion connected to both ends of the connecting portion, the bent portion is bent toward the anchor claw, the two bent portions are respectively located in adjacent cylindrical holes and elastically abut against the anchor claw, and the axial length of the pressure plate is greater than the spacing between adjacent cylindrical holes.

6. The self-locking hydraulic anchor according to claim 5, characterized in that: The curved portion includes an arc plate connected to the connecting portion and a fixing plate connected to the arc plate. The arc plate is located in the cylindrical hole and elastically abuts against the fluke. The fixing plate and the connecting portion are both fixed to the hydraulic anchor housing by pins.

7. The self-locking hydraulic anchor according to claim 3, characterized in that: A first sealing ring is provided between the fluke and the cylindrical hole.

8. The self-locking hydraulic anchor according to claim 3, characterized in that: The central rod is provided with second sealing rings at the upper and lower sides of the water injection hole.

9. The self-locking hydraulic anchor according to claim 3, characterized in that: A dust ring is provided between the upper end of the central core rod and the hydraulic anchor housing.

10. The self-locking hydraulic anchor according to claim 1 or 2, characterized in that: The core rod is spline-connected to the hydraulic anchor housing.

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