Underground open hole hydraulic anchor for oil field

Abstract

The invention belongs to the technical field of downhole tools, and provides an open hole hydraulic anchor for an oil field downhole. The open hole hydraulic anchor for the underground oil field comprises an anchor body, the anchor body is provided with a circulation path, the anchor body is provided with anchor holes which are distributed at equal intervals in the circumferential direction and communicated with the circulation path, pressing plates which are distributed at equal intervals in the circumferential direction are arranged on the outer side of the anchor body, pressing blocks are slidably connected into the anchor holes, the pressing blocks are provided with through grooves, and the through grooves are communicated with the anchor holes. The pressing plates are connected with the adjacent through grooves in a sliding mode, anchor flukes are arranged on the sides, away from the circulation path, of the pressing blocks, and springs are fixedly connected between the pressing blocks and the adjacent pressing plates. The side, close to the adjacent pressing block, of the pressing plate is sunken, the anchor fluke is prevented from being divided into two parts by the pressing plate, the anchor fluke is made to be a complete cylinder, meanwhile, the pressing plate slides in the through groove, then the anchor fluke and the pressing block are limited, the contact area of the anchor fluke is increased, and the anchoring effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of downhole tools, and in particular to a bare hole hydraulic anchor used in an oil field. Background Art

[0002] The open hole hydraulic anchor is a downhole anchoring tool used in open hole wells in oil fields. The hydraulic anchor is mainly composed of an anchor body, a pressure block, a spring, a pressure plate and other parts. It is installed on the upper end of the pipe string before use. During the anchoring process, the pipe string is anchored in the casing through the anchor claws on it based on the piston structure to prevent the casing from being deflected. There are two structures of the existing hydraulic anchor claws. One is that the anchor claw is composed of two semicircular anchor claws, and a pressure plate is passed through the two semicircular anchor claws. The pressure plate guides the movement of the pressure block, but the semicircular anchor claw will cause the contact area between it and the inner wall of the casing to be small. During the anchoring process of the hydraulic anchor, the anchor claw is easy to loosen, resulting in poor anchoring effect, and it is easy to cause axial displacement of the pipe string, resulting in failure of isolation. The other is a cylindrical pressure block, the anchor claw on it is a complete circle, so compared with the semicircular anchor claw, the contact area with the inner wall of the casing is large, but there is no pressure plate to guide the pressure block, resulting in an offset when the pressure block moves, which also causes axial displacement of the pipe string, thereby affecting the anchoring effect. Summary of the invention

[0003] In order to solve the technical problem that the contact area between the anchor claws of the existing hydraulic anchor and the inner wall of the casing is small, the present invention provides an open hole hydraulic anchor for use in oil field wells.

[0004] The technical solution of the present invention is: a naked hole hydraulic anchor for use in oilfield wells, comprising an anchor body, the anchor body being provided with a flow path, the anchor body being provided with anchor holes which are circumferentially evenly spaced and connected to the flow path, the outer side of the anchor body being provided with a pressure plate which is circumferentially evenly spaced, a pressure block being slidably connected in the anchor hole, the pressure block being provided with a through groove, the pressure plate being slidably connected to an adjacent through groove, an anchor claw being provided on a side of the pressure block away from the flow path, the pressure block being provided with a blind hole, a spring being fixedly connected between the pressure block and the adjacent pressure plate, an O-ring being provided on a side of the outer annular surface of the pressure block away from the adjacent pressure plate, and a side of the pressure plate close to the adjacent through groove being recessed toward the anchor body.

[0005] As a preferred solution, the distance from the fluke to the central axis of the anchor body is smaller than the distance from the outer side of the non-recessed portion of the pressure plate to the central axis of the anchor body.

[0006] As a preferred solution, it also includes an anti-trigger mechanism distributed at equal intervals in the circumferential direction, the anti-trigger mechanism is arranged on the side of the adjacent pressure block close to the flow path, the anti-trigger mechanism is used to prevent the pressure block from being triggered prematurely, the anti-trigger mechanism includes an insert block, the pressure block is provided with a first rectangular groove, the insert block is slidably connected to the adjacent first rectangular groove, a pressure plug is fixedly connected to the side of the insert block close to the flow path, the pressure plug is slidably connected to the adjacent anchor hole, an elastic member is fixedly connected between the pressure plug and the adjacent pressure block, the pressure block is provided with a locking component, and the locking component is used to limit the adjacent pressure block.

[0007] As a preferred solution, the locking component includes a rectangular frame, the insert block is provided with a slide groove, the rectangular frame is slidably connected to the adjacent slide groove, the pressure block is provided with a second rectangular groove, the rectangular frame is slidably connected to the adjacent second rectangular groove, the pressure block is provided with a guide groove, the guide groove is slidably connected to an insert rod fixed to the adjacent rectangular frame, and the insert rod is fixed to a limiting column on one side away from the adjacent rectangular frame.

[0008] As a preferred solution, the limiting column is fixedly connected with a resistance disk, the anchor body is provided with sealed cavities distributed at equal intervals in the circumferential direction, and the resistance disk is slidably connected with adjacent sealed cavities.

[0009] As a preferred solution, both sides of the slide groove are deflected downward.

[0010] As a preferred solution, the diameter of the limiting column is larger than the diameter of the insert rod, the pressing block is provided with symmetrically distributed limiting holes, and the limiting column is limitedly matched with adjacent limiting holes.

[0011] As a preferred solution, the resistance disk is provided with a through hole, the diameter of the through hole of the resistance disk is smaller than the aperture of the sealing cavity, and is used to reduce the resistance of the resistance disk when it moves.

[0012] As a preferred solution, the shape of the middle portion of the slide groove is set to be wavy, so as to increase the resistance when the adjacent rectangular frames move.

[0013] As a preferred solution, the sealing cavity is filled with damping oil.

[0014] Beneficial effect: the present invention prevents the pressure plate from dividing the anchor claw into two by making one side of the pressure plate close to the adjacent pressure block concave, so that the anchor claw is a complete cylinder, and the pressure plate slides in the through groove, thereby limiting the anchor claw and the pressure block, thereby increasing the contact area of ​​the anchor claw and improving the anchoring effect. Before anchoring, the hydraulic anchor gives priority to the problem of early anchoring caused by the change of downhole pressure. When the downhole pressure changes, the pressure block is limited by the limiting column to avoid damage to the anchor claw. By further considering that the instantaneous pressure in the well will instantly exceed the anchoring pressure, on the basis of limiting the pressure block, a condition for releasing the limit of the pressure block is added, that is, the limit of the pressure block will be released only after the continuous pressure exceeds the anchoring pressure for a period of time, which further increases the stability of the hydraulic anchor, and buffers the pressure block after the limit is released to avoid the high pressure causing the anchor claw to hit the inner wall of the casing. At the same time, after the anchoring process is completed, the pressure block is fixed again, which improves the stability of the hydraulic anchor during the anchoring process, and finally the anchor body is stably anchored to the casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is a cross-sectional view of the three-dimensional structure of the present invention; Figure 3 It is a three-dimensional structural schematic diagram of parts such as the anchor hole and the sealing cavity of the present invention; Figure 4 It is a three-dimensional structural schematic diagram of the anti-trigger mechanism of the present invention; Figure 5 It is a three-dimensional structural schematic diagram of the locking component of the present invention; Figure 6 It is a cross-sectional view of the three-dimensional structure of the compact of the present invention; Figure 7 It is a schematic diagram of the three-dimensional structure of the rectangular frame and the slide groove of the present invention.

[0016] The meanings of the reference numerals in the figure are: 1-anchor body, 101-circulation path, 102-anchor hole, 103-sealed cavity, 2-pressure plate, 3-pressure block, 301-through groove, 302-anchor claw, 303-first rectangular groove, 304-second rectangular groove, 305-guide groove, 306-limiting hole, 4-spring, 5-o-ring, 6-insertion block, 601-slide groove, 7-pressure plug, 8-elastic member, 9-rectangular frame, 10-insertion rod, 11-limiting column, 12-resistance disk. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Example 1: A bare hole hydraulic anchor for use in an oil field well, such as Figure 1-Figure 5As shown, it includes an anchor body 1, the anchor body 1 is provided with a flow path 101, the anchor body 1 is provided with nine anchor holes 102 which are circumferentially evenly spaced and connected to the flow path 101, each layer has three circumferentially distributed anchor holes 102, and there are three layers in total. Three pressing plates 2 which are circumferentially evenly spaced are provided on the outer side of the anchor body 1, a pressing block 3 is slidably connected in the anchor hole 102, a through groove 301 is provided on the side of the pressing block 3 away from the flow path 101, the through groove 301 longitudinally penetrates the adjacent pressing block 3, the pressing plate 2 is slidably connected with the adjacent through groove 301, the pressing plate 2 is used to guide and limit the pressing block 3, an anchor claw 302 is provided on the side of the pressing block 3 away from the flow path 101, when the pressure in the flow path 101 increases, the pressing block 3 moves away from the flow path 101, and the pressing block 3 drives the anchor claw 302 thereon to approach the inner wall of the casing and perform For anchoring, two blind holes symmetrically distributed up and down are provided on one side of the pressure block 3 close to the adjacent pressure plate 2, a spring 4 is fixedly connected between the pressure block 3 and the adjacent pressure plate 2, the pressure block 3 is close to the adjacent pressure plate 2, the two springs 4 are compressed and finally enter the adjacent blind holes of the pressure block 3, an O-ring 5 is provided on the side of the outer ring surface of the pressure block 3 away from the adjacent pressure plate 2, the O-ring 5 is used to increase the sealing between the pressure block 3 and the anchor body 1, the side of the pressure plate 2 close to the adjacent through groove 301 is recessed toward the anchor body 1, the contact area between the anchor claw 302 and the casing is increased, and the anchoring effect is improved, the distance from the anchor claw 302 to the central axis of the anchor body 1 is less than the distance from the outer side of the non-recessed part of the pressure plate 2 to the central axis of the anchor body 1, in the process of the hydraulic anchor being placed in the well, the contact and damage of the anchor claw 302 and the inner wall of the casing are avoided, resulting in the subsequent poor fixing effect of the anchor claw 302.

[0019] The purpose of the hydraulic anchor is to anchor the anchor body 1 and fix it in the casing. Before the hydraulic anchor is anchored, the hydraulic anchor is placed underground. During the process of placing the hydraulic anchor underground, since the distance between the anchor claw 302 and the central axis of the anchor body 1 is smaller than the distance between the outer side of the pressure plate 2 and the central axis of the anchor body 1, the pressure plate 2 will contact the inner wall of the casing, while the anchor claw 302 will not contact the inner wall of the casing, thereby avoiding damage to the contact between the anchor claw 302 and the inner wall of the casing, resulting in a poor fixing effect of the subsequent anchor claw 302. The hydraulic anchor recesses the side of the pressure plate 2 close to the adjacent pressure block 3 to avoid the pressure plate 2 dividing the anchor claw 302 into two (the existing anchor claw 302 is in the shape of two semicircles, the middle of which is divided by the pressure plate 2), making the anchor claw 302 a complete cylinder, and at the same time the pressure plate 2 slides in the through groove 301, thereby And the pressure block 3 is limited, thereby increasing the contact area of ​​the anchor claw 302 and improving the anchoring effect. After the hydraulic anchor is placed in the specified position, it is necessary to pressurize the anchor body 1. After the packer above the hydraulic anchor completes the isolation, the pressure in the anchor body 1 increases to assist the fixation of the hydraulic anchor. The specific steps are as follows: the pressure in the anchor body 1 increases, pushing the pressure block 3 away from the flow path 101. Taking a pressure block 3 in the middle of the right side as an example, the pressure on the left side of the pressure block 3 increases, and the pressure block 3 moves to the right to squeeze the two springs 4. The two springs 4 are compressed, and the pressure block 3 drives the O-ring 5 to move to the right. The O-ring 5 is used to seal the pressure block 3 and the anchor hole 102. The anchor claw 302 continues to approach the inner wall of the casing and contacts it. When the pressure in the flow path 101 is large enough, the anchor claw 302 fixes the anchor body 1 on the inner wall of the casing, and the anchor body 1 is fixed.

[0020] Hydraulic anchor recovery process: When the hydraulic anchor needs to be recovered, the pressure in the flow path 101 decreases, the two springs 4 reset to drive the pressure block 3 to move left, and the anchor claw 302 gradually moves away from the inner wall of the casing. When the pressure in the flow path 101 is restored, the hydraulic anchor recovery process is completed.

[0021] Embodiment 2: Based on embodiment 1, Figure 2-Figure 5 As shown, it also includes an anti-trigger mechanism distributed at equal intervals in the circumferential direction. The anti-trigger mechanism is arranged on a side of the adjacent pressure block 3 close to the flow path 101. The anti-trigger mechanism is used to prevent the pressure block 3 from being triggered in advance, so as to prevent the anchor claw 302 from being damaged by contacting the inner wall of the casing in advance. The anti-trigger mechanism includes an insert block 6. A first rectangular groove 303 is arranged transversely through the middle of the pressure block 3. The insert block 6 is slidably connected to the adjacent first rectangular groove 303. A pressure plug 7 is fixedly connected to the side of the insert block 6 away from the adjacent pressure plate 2. The pressure plug 7 is slidably connected to the adjacent anchor hole 102. An elastic member 8 is fixedly connected between the pressure plug 7 and the adjacent pressure block 3. The elastic member 8 is a spring. When the pressure in the flow path 101 increases, the pressure plug 7 is away from the adjacent flow path 101, the elastic member 8 is compressed, and the pressure plug 7 drives the insert block 6 away from the adjacent flow path 101. The pressure block 3 is provided with a locking component, which is used to limit the adjacent pressure block 3.

[0022] like Figure 4-Figure 7 As shown, the locking component includes a rectangular frame 9, and the insert block 6 is provided with a slide groove 601. The lower side of the rectangular frame 9 is slidably connected to the adjacent slide groove 601, and the two sides of the slide groove 601 are deflected downward. In the initial state, taking the pressing block 3 on the right as an example, the lower side of the rectangular frame 9 is located on the right side of the slide groove 601. When the insert block 6 moves to the right, the rectangular frame 9 is limited by the slide groove 601 and moves upward. The shape of the middle part of the slide groove 601 is set to be wavy. When the insert block 6 moves to the right, the middle part of the slide groove 601 is aligned with the rectangular frame 9. The lower side contacts, the speed of the plug block 6 moving to the right is reduced, the pressing block 3 is provided with a second rectangular groove 304, the second rectangular groove 304 is located on the upper side of the first rectangular groove 303 and is connected thereto, the rectangular frame 9 is slidably connected to the adjacent second rectangular groove 304, the second rectangular groove 304 is used to guide the rectangular frame 9, the pressing block 3 is provided with a guide groove 305 located on the upper side of the second rectangular groove 304 and connected thereto, the guide groove 305 is slidably connected to the plug rod 10 fixed to the adjacent rectangular frame 9, and the upper side of the plug rod 10 is fixed The limiting column 11 is connected, and the diameter of the limiting column 11 is larger than the diameter of the insertion rod 10 to prevent the limiting column 11 from sliding along the second rectangular groove 304. Two symmetrically distributed limiting holes 306 are provided on the upper side of the pressing block 3. The limiting column 11 is limitedly matched with the adjacent limiting holes 306. Before anchoring, the lower end of the limiting column 11 is inserted into the limiting hole 306 away from the flow path 101. After anchoring, the lower end of the limiting column 11 is inserted into the limiting hole 306 close to the flow path 101, and the upper end of the limiting column 11 A resistance disk 12 is fixedly connected, and the anchor body 1 is provided with sealed cavities 103 distributed at equal intervals in the circumferential direction. The resistance disk 12 is slidingly connected to the adjacent sealed cavities 103. The resistance disk 12 is provided with three through holes distributed in the circumferential direction. The diameter of the through holes of the resistance disk 12 is smaller than the aperture of the sealed cavity 103. The sealed cavity 103 is filled with damping oil. When the resistance disk 12 moves upward or downward, the damping oil in the sealed cavity 103 continuously passes through the through holes of the resistance disk 12, thereby increasing the resistance of the resistance disk 12 when it moves.

[0023] The following process takes the pressure block 3 in the middle of the right side as an example. Before the hydraulic anchor is anchored, the downhole pressure keeps changing, and the constantly fluctuating pressure will cause the hydraulic anchor to anchor in advance. The specific reasons are as follows: When the pressure in the anchor body 1 increases, the pressure block 3 will move to the right, and the pressure block 3 will cause the anchor claw 302 thereon to extend to the right and contact the inner wall of the casing. The contact between the anchor claw 302 and the inner wall of the casing will cause the anchor claw 302 to be damaged. Therefore, in order to solve the above problem, it is necessary to limit the pressure block 3 before anchoring, that is, when the pressure in the anchor body 1 fluctuates, to avoid the hydraulic anchor from anchoring in advance. The specific operation is as follows: When the pressure in the anchor body 1 is normal pressure, since the limit column 11 is inserted into the limit hole 306 on the right side, and the limit column 11 cannot move to the right, the pressure block 3 cannot move to the right, ensuring that the pressure block 3 is in a stable state under normal pressure.

[0024] When the pressure in the anchor body 1 increases, this pressure does not exceed the anchoring pressure, the pressure in the flow path 101 increases, the pressure on the left side of the pressure plug 7 increases and moves to the right, the pressure plug 7 drives the plug block 6 to move to the right relative to the pressure block 3, the elastic member 8 is compressed, and when the plug block 6 moves to the right, the slide groove 601 moves to the right at the same time, and the right side of the slide groove 601 squeezes the rectangular frame 9 upward to make it move upward, and the rectangular frame 9 drives the insertion rod 10 and the limiting column 11 to move upward, but because the pressure in the flow path 101 does not exceed the anchoring pressure, the limiting column 11 will not move out of the limiting hole 306 on the right side, the pressure block 3 is limited by the limiting column 11, and the pressure plug 7 cannot pass. The pressure block 3 is squeezed to the right by the elastic member 8. When the pressure in the flow path 101 is restored, the elastic member 8 is reset to drive the pressure plug 7 to move to the left. The pressure plug 7 drives the insert block 6 to move to the left. The slide groove 601 causes the rectangular frame 9 to move downward. The rectangular frame 9 drives the limit column 11 to move downward through the insertion rod 10. Therefore, when the pressure in the flow path 101 fluctuates, the insert block 6 and the pressure plug 7 will only move slightly to the left and right, and the rectangular frame 9, the insertion rod 10 and the limit column 11 will only move slightly up and down, and the limit column 11 will not release the limit on the pressure block 3. Therefore, when the pressure in the anchor body 1 fluctuates, the pressure block 3 is kept in a stable state to avoid damage to the anchor claw 302.

[0025] When the pressure in the anchor body 1 increases and the pressure instantly exceeds the anchoring pressure, at this time, the rectangular frame 9 drives the insertion rod 10 and the limit column 11 to move upward instantly, and the limit column 11 drives the resistance disk 12 to move upward instantly. When the resistance disk 12 moves upward, since the aperture of the blind hole of the resistance disk 12 is small, the damping oil on the upper side of the sealed cavity 103 will not move downward quickly through the blind hole of the resistance disk 12, which increases the resistance of the resistance disk 12 when it moves upward instantly, making it difficult for the resistance disk 12 to move upward instantly. Therefore, the limit column 11 will still limit the pressure block 3. In summary, even if the instantaneous pressure in the anchor body 1 exceeds the anchoring pressure, the hydraulic anchor will not be anchored in advance.

[0026] When the pressure in the anchor body 1 continuously reaches the anchoring pressure, the hydraulic anchor performs the anchoring process, and the specific process is as follows: the left side of the pressure plug 7 is first pressurized and moves to the right, the elastic member 8 is compressed, and the pressure plug 7 drives the plug block 6 to move to the right, and the lower side of the rectangular frame 9 gradually enters the middle wave portion of the slide groove 601 from the inclined portion on the right side thereof, and the rectangular frame 9 drives the limit column 11 and the resistance disk 12 to move upward through the insertion rod 10, and the lower end of the limit column 11 gradually moves out of the limit hole 306 on the right side, and the damping oil on the upper side of the resistance disk 12 enters its lower side through the through hole of the resistance disk 12, and when the lower side of the rectangular frame 9 enters the right end of the middle wave portion of the slide groove 601, the lower end of the limit column 11 moves out of the limit hole 306 on the right side, and at this time, the limit of the pressure block 3 is released.

[0027] After the limit of the pressing block 3 is released, the following situation will occur: the pressure plug 7 drives the pressing block 3 to move rapidly to the right through the elastic member 8, and the pressing block 3 moves to the right along the first rectangular groove 303, so that the anchor claw 302 quickly hits the inner wall of the casing. The specific reasons are as follows: since the resistance disk 12 moves slowly in the damping oil of the sealing cavity 103, when the limit of the pressing block 3 is released, the pressure in the flow path 101 has been accumulated for a period of time, and after the limit of the pressing block 3 is released, the pressure released after the limit of the pressing block 3 is released is relatively large, so the anchor claw 302 may be damaged. In order to avoid the above situation, the slide groove 60 is The shape of the middle part of 1 is set to be wavy. When the limit of the pressure block 3 is released, the pressure plug 7 drives the plug 6 to move rightward, and the rectangular frame 9 moves from the right side of the wave part of the slide groove 601 to the left side. In the process of the rectangular frame 9 moving from the right side of the wave part of the slide groove 601 to the left side, the rectangular frame 9 moves up and down continuously, and the resistance plate 12 moves up and down. The damping oil in the sealed cavity 103 slows down the speed of the resistance plate 12 moving up and down, and at the same time slows down the speed of the rectangular frame 9 moving up and down, reduces the speed of the plug 6 and the pressure block 3 moving to the right, and buffers the pressure suddenly released by the pressure block 3 to prevent the anchor claw 302 from directly hitting the inner wall of the casing.

[0028] Through the buffering of the wavy part of the slide groove 601 and the damping oil in the sealing cavity 103, the pressure block 3 drives the anchor claw 302 to move slowly to the right and close to the inner wall of the casing. When the pressure block 3 moves to the right, the two springs 4 are compressed. When the lower side of the rectangular frame 9 is located on the left side of the wavy part of the slide groove 601, the limit column 11 is located above the left limit hole 306. The right side of the pressure block 3 contacts the left side of the pressure plate 2 and cannot move to the right. The two springs 4 are pressed into the blind holes of the adjacent pressure blocks 3. At this time, the pressure in the flow path 101 is still increasing. Then the insertion block 6 continues to move to the right. The lower side of the rectangular frame 9 is gradually moved downward by the limit of the left side of the slide groove 601. The rectangular frame 9 drives the limit column 11 to move downward through the insertion rod 10 and inserts it into the limit hole 306 on the left. After being limited for the second time, the anchoring process is completed. After the anchor claw 302 contacts the inner wall of the casing, the pressure block 3 is limited again to avoid the hydraulic anchor being unlocked midway during the anchoring process. During the anchoring process, although the pressure in the flow path 101 is in a high pressure state, the pressure in the flow path 101 will still fluctuate. When the pressure in the flow path 101 is temporarily reduced, the elastic member 8 is reset, the pressure plug 7 moves to the left, and the pressure plug 7 drives the plug 6 to move to the left. The lower side of the rectangular frame 9 is limited by the left side of the slide groove 601 and moves upward, but the rectangular frame 9 will not move to the wave part of the slide groove 601, and the limiting column 11 will not release the limit on the pressure block 3. When the pressure in the flow path 101 is restored, the rectangular frame 9 continues to be on the left side of the slide groove 601.

[0029] During the hydraulic anchor recovery process, the pressure in the flow path 101 is reduced to normal pressure, the elastic member 8 is reset to drive the pressure plug 7 to move to the left, the pressure plug 7 drives the plug 6 to move to the left relative to the pressure block 3, the lower side of the rectangular frame 9 enters the left side of its wave portion from the left side of the slide groove 601, the limiting column 11 moves out from the left limiting hole 306, the two springs 4 are reset to drive the pressure block 3 to move to the left, the pressure block 3 drives the anchor claw 302 to move to the left and gradually away from the inner wall of the casing, the lower side of the rectangular frame 9 moves to the right along the slide groove 601 (relative to the plug 6), and finally the rectangular frame 9 is located on the right side of the slide groove 601, the limiting column 11 is stuck in the limiting hole 306 on the right, and when the elastic force of the elastic member 8 and the two springs 4 is restored, the anchoring process is completed.

[0030] In summary, before anchoring, the hydraulic anchor gives priority to the problem of early anchoring caused by changes in downhole pressure. When the downhole pressure changes, the pressure block 3 is limited by the limit column 11 to avoid damage to the anchor claw 302. By further considering that the instantaneous pressure in the well will instantly exceed the anchoring pressure, therefore, on the basis of limiting the pressure block 3, a condition for releasing the limit on the pressure block 3 is added, that is, the limit on the pressure block 3 will be released only after the continuous pressure exceeds the anchoring pressure for a period of time, which further increases the stability of the hydraulic anchor, and buffers the pressure block 3 after the limit is released to avoid the high pressure causing the anchor claw 302 to hit the inner wall of the casing. At the same time, after the anchoring process is completed, the pressure block 3 is fixed again, which improves the stability of the hydraulic anchor during the anchoring process, and finally the anchor body 1 is stably anchored in the casing.

[0031] It should be understood that the above description is only for exemplary purposes and is not meant to limit the present invention. Those skilled in the art will appreciate that variations of the present invention will be included within the scope of the claims herein.

Claims

1. A bare hole hydraulic anchor for use in oil wells, characterized by: The invention comprises an anchor body (1), wherein the anchor body (1) is provided with a flow path (101), the anchor body (1) is provided with anchor holes (102) which are circumferentially evenly spaced and communicated with the flow path (101), the outer side of the anchor body (1) is provided with a pressure plate (2) which is circumferentially evenly spaced, a pressure block (3) is slidably connected in the anchor hole (102), the pressure block (3) is provided with a through groove (301), the pressure plate (2) is slidably connected with the adjacent through groove (301), a fluke (302) is provided on a side of the pressure block (3) away from the flow path (101), the pressure block (3) is provided with a blind hole, a spring (4) is fixedly connected between the pressure block (3) and the adjacent pressure plate (2), an O-ring (5) is provided on a side of the outer annular surface of the pressure block (3) away from the adjacent pressure plate (2), and a side of the pressure plate (2) close to the adjacent through groove (301) is recessed toward the anchor body (1).

2. The open hole hydraulic anchor for use in oil wells according to claim 1 is characterized by: The distance between the fluke (302) and the central axis of the anchor body (1) is smaller than the distance between the outer side of the non-recessed portion of the pressure plate (2) and the central axis of the anchor body (1).

3. The open hole hydraulic anchor for use in oil wells according to claim 1 is characterized by: The anti-trigger mechanism is also provided with circumferentially equidistantly distributed anti-trigger mechanisms, the anti-trigger mechanisms being arranged on a side of the adjacent pressing block (3) close to the flow path (101), the anti-trigger mechanisms being used to prevent the pressing block (3) from being triggered in advance, the anti-trigger mechanisms comprising an insert block (6), the pressing block (3) being provided with a first rectangular groove (303), the insert block (6) being slidably connected to the adjacent first rectangular groove (303), a pressure plug (7) being fixedly connected to a side of the insert block (6) close to the flow path (101), the pressure plug (7) being slidably connected to an adjacent anchor hole (102), an elastic member (8) being fixedly connected between the pressure plug (7) and the adjacent pressing block (3), the pressing block (3) being provided with a locking component, the locking component being used to limit the adjacent pressing block (3).

4. The open hole hydraulic anchor for use in oil wells according to claim 3 is characterized by: The locking component comprises a rectangular frame (9), the insert block (6) is provided with a slide groove (601), the rectangular frame (9) is slidably connected to the adjacent slide groove (601), the pressing block (3) is provided with a second rectangular groove (304), the rectangular frame (9) is slidably connected to the adjacent second rectangular groove (304), the pressing block (3) is provided with a guide groove (305), the guide groove (305) is slidably connected to an insert rod (10) fixedly connected to the adjacent rectangular frame (9), and the insert rod (10) is fixedly connected to a limiting column (11) on a side away from the adjacent rectangular frame (9).

5. The open hole hydraulic anchor for use in oil wells according to claim 4 is characterized by: The limiting column (11) is fixedly connected with a resistance disk (12); the anchor body (1) is provided with sealing cavities (103) distributed at equal intervals in the circumferential direction; the resistance disk (12) is slidably connected to adjacent sealing cavities (103).

6. The open hole hydraulic anchor for use in oil wells according to claim 4 is characterized by: Both sides of the slide groove (601) are deflected downward.

7. The open hole hydraulic anchor for use in oil wells according to claim 5 is characterized by: The diameter of the limiting column (11) is greater than the diameter of the insertion rod (10), the pressing block (3) is provided with symmetrically distributed limiting holes (306), and the limiting column (11) is limitedly matched with adjacent limiting holes (306).

8. The open hole hydraulic anchor for use in oil wells according to claim 5 is characterized by: The resistance disk (12) is provided with a through hole, the diameter of the through hole of the resistance disk (12) being smaller than the aperture of the sealed cavity (103), and being used to reduce the resistance of the resistance disk (12) when it moves.

9. The open hole hydraulic anchor for use in oil wells according to claim 6 is characterized by: The shape of the middle portion of the slide groove (601) is set to be wavy, so as to increase the resistance when the adjacent rectangular frame (9) moves.

10. The open hole hydraulic anchor for use in oil wells according to claim 8, characterized in that: The sealed cavity (103) is filled with damping oil.

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