Self-locking hydraulic anchor

Abstract

The invention provides a self-locking hydraulic anchor which comprises a hydraulic anchor body, a sliding mandrel capable of making contact with the hydraulic anchor body, an elastic piece connected with the sliding mandrel, a one-way valve and a sealing mandrel. The one-way valve comprises a valve seat arranged in the hydraulic anchor body and a valve element capable of being separated from or making contact with the valve seat. A part of the outer wall of the sealing mandrel and a part of the inner wall of the hydraulic anchor body form a closed cavity, the first end of the one-way valve is communicated with the closed cavity, the second end of the one-way valve is communicated with an inner tubular column of the sliding mandrel, and the sliding mandrel can abut against the hydraulic anchor body under the action of the elastic piece and push the valve element to leave the valve seat at the same time. And the valve element can move away from the hydraulic anchor body under the action of external force, so that the valve element is in contact with the hydraulic anchor body. According to the self-locking type hydraulic anchor, in the reservoir transformation period, the pressure in the self-locking type hydraulic anchor is always larger than the pressure borne by the outside, so that the anchor fluke is in a locked state, a packer is prevented from being unblocked, and an oil pipe is prevented from being communicated with a sleeve.

Description

Technical Field

[0001] The invention relates to the technical field of drilling equipment, in particular to a self-locking hydraulic anchor. Background Art

[0002] Conventional hydraulic anchors rely on the piston force generated on the anchor claws by the pressure difference between the hydraulic anchor's internal pressure and the pressure on the outside of the hydraulic anchor to push the anchor claws out and bite them on the casing to achieve the purpose of anchoring. Specifically, when the pressure inside the hydraulic anchor is greater than the pressure on the outside of the hydraulic anchor, the anchor claws of the hydraulic anchor extend, so that the hydraulic anchor plays an anchoring role. Conversely, when the pressure inside the hydraulic anchor is less than or equal to the pressure on the outside of the hydraulic anchor, the anchor claws of the hydraulic anchor are retracted.

[0003] During the process of oil and gas well reservoir transformation, the construction pump pressure may suddenly drop significantly, which will cause the pressure inside the hydraulic anchor to no longer be greater than the pressure outside the hydraulic anchor. The anchor claws of the hydraulic anchor will be retracted, and the anchoring force acting on the casing will fail. The "upward force" exerted on the upper tubing due to the "cold shrinkage" after the acid enters directly acts on the packer, which can easily cause the packer to be accidentally unsealed, and the oil pipe and casing to be connected, eventually causing the casing to be subjected to high pressure or corroded by acid and corrosive fluids. Summary of the invention

[0004] One purpose of the present invention is to provide a self-locking hydraulic anchor that can increase and store the pressure in a closed cavity, so that during reservoir reconstruction, the pressure inside the self-locking hydraulic anchor is always greater than the pressure outside, so that the anchor claw is in a locked state, avoiding the packer from being unsealed, thereby avoiding the oil pipe from being connected to the casing, and effectively protecting the casing.

[0005] According to the present invention, a self-locking hydraulic anchor is provided, comprising: a hydraulic anchor body, a sliding core shaft capable of contacting the hydraulic anchor body, an elastic member connected to the sliding core shaft, a one-way valve, and a sealing core shaft, the one-way valve comprising a valve seat arranged inside the hydraulic anchor body and a valve core capable of being separated from or in contact with the valve seat, a portion of the outer wall of the sealing core shaft and a portion of the inner wall of the hydraulic anchor body form a closed cavity, a first end of the one-way valve is communicated with the closed cavity, and a second end thereof is communicated with an internal pipe column of the sliding core shaft, the sliding core shaft can, under the action of the elastic member, press against the hydraulic anchor body and simultaneously push the valve core away from the valve seat, and can also, under the action of an external force, move in a direction away from the hydraulic anchor body so that the valve core contacts the valve seat.

[0006] In a preferred embodiment, the valve core protrudes from the end surface of the hydraulic anchor body so that when the sliding core shaft is in pressure contact with the hydraulic anchor body, the sliding core shaft can contact the valve core to push the valve core away from the valve seat.

[0007] In a preferred embodiment, relative to the hydraulic anchor body, the sealing core shaft is close to the interior of the self-locking hydraulic anchor, a portion of the outer wall of the sealing core shaft abuts against a portion of the inner wall of the hydraulic anchor body, and sealing rings are provided at both ends of the contact position, a portion of the outer wall of the sealing core shaft does not contact a portion of the inner wall of the hydraulic anchor body and forms the closed cavity.

[0008] In a preferred embodiment, the self-locking hydraulic anchor further comprises a first joint provided at the first end of the hydraulic anchor body, which has a step portion, the inner wall of the step portion abuts against the outer wall of the sliding core shaft and is sealed by a sealing ring at the contact position.

[0009] In a preferred embodiment, the first side end face of the sliding core shaft can be pressed into contact with the hydraulic anchor body, and the elastic member is connected to the second side end face of the sliding core shaft opposite to the first side end face. The elastic member is located in the space surrounded by the side end face of the step portion, the inner wall of the first joint and the second side end face of the sliding core shaft, and the elastic member is also connected to the side end face of the step portion.

[0010] In a preferred embodiment, a notch is provided on the sealing core shaft, and the second end of the one-way valve is connected to the inner pipe column of the sliding core shaft through the notch.

[0011] In a preferred embodiment, the self-locking hydraulic anchor also includes a second joint arranged at the second end of the hydraulic anchor body, which has a step, the outer wall of the step abuts against the inner wall of the hydraulic anchor body, and is sealed by a sealing ring at the contact position, and the side end surface of the step also abuts against the side end surface of the sealing core shaft to fix the sealing core shaft.

[0012] In a preferred embodiment, the hydraulic anchor body has two groups of anchor claws evenly distributed at 120 degrees inside, which are used to anchor the self-locking hydraulic anchor on the casing.

[0013] In a preferred embodiment, the elastic member is a butterfly valve.

[0014] In a preferred embodiment, the self-locking hydraulic anchor further comprises a double female joint connected to the end of the sliding mandrel away from the hydraulic anchor body, which is used to convert a flat male buckle into a female buckle.

[0015] The present invention forms a closed cavity by making a part of the outer wall of the sealing core shaft and a part of the inner wall of the hydraulic anchor body, the first end of the one-way valve is connected to the closed cavity and the second end of the one-way valve is connected to the inner pipe column of the sliding core shaft, the sliding core shaft can be pressed and contacted with the hydraulic anchor body under the action of the elastic member and simultaneously push the valve core to leave the valve seat, and the sliding core shaft can also move in the direction away from the hydraulic anchor body under the action of an external force so that the valve core contacts the valve seat. During the reservoir transformation, the sliding core shaft moves in the direction away from the hydraulic anchor body, and the valve core of the one-way valve is released and reset to contact the valve seat. The fluid in the inner pipe string of the sealing core shaft flows to the second end of the one-way valve through the groove, and flows out from the first end of the one-way valve and enters the closed cavity, and the fluid in the closed cavity cannot flow out, thereby maintaining the pressure in the closed cavity, so that the pressure inside the self-locking hydraulic anchor is always greater than the pressure outside the self-locking hydraulic anchor, and the anchor claws of the hydraulic anchor body are always in an extended state, thereby avoiding the situation where the pressure inside the hydraulic anchor is no longer greater than the pressure outside the hydraulic anchor due to a sudden and significant decrease in the construction pump pressure, avoiding the unsealing of the packer, thereby avoiding the connection between the oil pipe and the casing, and effectively protecting the casing.

[0016] The present invention enables the first side end face of the sliding core shaft to be in pressure contact with the hydraulic anchor body, an elastic part is connected to the second side end face of the sliding core shaft opposite to the first side end face, the elastic part is located in a space surrounded by the side end face of the step portion, the inner wall of the first joint and the second side end face of the sliding core shaft, and the elastic part is also connected to the side end face of the step portion, which can effectively protect the elastic part and extend its service life.

[0017] The present invention has a valve core protruding from the end surface of the hydraulic anchor body so that when the sliding core shaft is in pressure contact with the hydraulic anchor body, the sliding core shaft can contact the valve core to push the valve core away from the valve seat, thereby facilitating the control of whether the one-way valve fails or not by moving the sliding core shaft, thereby facilitating the control of the flow direction of the fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The overall structure of the self-locking hydraulic anchor according to the present invention is schematically shown.

[0019] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0020] like Figure 1As shown, the self-locking hydraulic anchor 100 of the present invention comprises: a hydraulic anchor body 6 having an anchor claw 4 inside, a sliding mandrel 13 capable of approaching and contacting the hydraulic anchor body 6, an elastic member 11 connected to the sliding mandrel 13, a one-way valve a, and a sealing mandrel 5, wherein the one-way valve a comprises a valve seat 8 disposed inside the hydraulic anchor body 6 and a valve core 9 capable of being separated from or contacting the valve seat 8, a part of the outer wall of the sealing mandrel 5 and a part of the inner wall of the hydraulic anchor body 6 form a closed cavity s, a first end of the one-way valve a is connected to the closed cavity s, and a second end of the one-way valve a is connected to the closed cavity s. The internal tubular column of the sliding core shaft 13 is connected, and the sliding core shaft 13 can be pressed and contacted with the hydraulic anchor body 6 under the action of the elastic member 11 and simultaneously push the valve core 9 away from the valve seat 8, and the sliding core shaft 13 can also be moved in the direction away from the hydraulic anchor body 6 under the action of an external force, so that the valve core 9 contacts the valve seat 8, wherein the "external force" can be the force generated by the thermal expansion and contraction of the upper tubular column during reservoir transformation, and this force is the "lifting force", which can pull the sliding core shaft 13 toward the wellhead, thereby making the sliding core shaft 13 away from the hydraulic anchor body 6.

[0021] The present invention forms a closed cavity s by making a part of the outer wall of the sealing core shaft 5 and a part of the inner wall of the hydraulic anchor body 6, the first end of the one-way valve a is communicated with the closed cavity s and the second end of the one-way valve a is communicated with the internal pipe column of the sliding core shaft 13, the sliding core shaft 13 can be pressed and contacted with the hydraulic anchor body 6 under the action of the elastic member 11 and simultaneously push the valve core 9 to leave the valve seat 8, and the sliding core shaft 13 can also move in the direction away from the hydraulic anchor body 6 under the action of an external force, so that the valve core 9 contacts the valve seat 8. During the reservoir transformation, the sliding core shaft 13 moves in the direction away from the hydraulic anchor body 6, the valve core 9 of the one-way valve a is released and reset to contact with the valve seat 8, and the closed cavity s is formed. The fluid in the internal pipe column of the sealing core shaft 5 flows to the second end of the one-way valve a through the notch 10, and flows out from the first end of the one-way valve a and enters the closed cavity s, and the fluid in the closed cavity s cannot flow out, thereby maintaining the pressure in the closed cavity s, so that the pressure inside the self-locking hydraulic anchor 100 is always greater than the pressure outside the self-locking hydraulic anchor 100, and the anchor claw 4 of the hydraulic anchor body 6 is always in an extended state, that is, the anchor claw is locked, thereby avoiding the situation where the pressure inside the hydraulic anchor is no longer greater than the pressure outside the hydraulic anchor due to a sudden and significant decrease in the construction pump pressure, thereby avoiding the unsealing of the packer, thereby avoiding the oil pipe and the casing from being connected, and effectively protecting the casing.

[0022] The self-locking hydraulic anchor 100 of the present invention further includes a first joint 12 and a second joint 1, wherein the first end of the hydraulic anchor body 6 is provided with the first joint 12, and the second end of the hydraulic anchor body 6 is provided with the second joint 1. The first joint 12 and the second joint 1 are respectively provided at the two ends of the hydraulic anchor body 6 along the axial direction of the self-locking hydraulic anchor and are both in contact with and fixedly connected to the hydraulic anchor body 6. In actual working conditions, the first joint 12 is closer to the wellhead than the second joint 1. In one or more embodiments, the first joint 12, the second joint 1 and the hydraulic anchor body 6 are respectively connected by threads at the contact position and are locked and fixed by the set screw 7 and the set screw 2 to prevent accidental disengagement. The first joint 12, the second joint 1 and the hydraulic anchor body 6 are respectively sealed by sealing rings at the contact position.

[0023] In one or more embodiments, the second joint 1 has a step 15, the outer wall of the step 15 abuts against the inner wall of the hydraulic anchor body 6, and is sealed by a sealing ring at the contact position, and the side end surface of the step 15 also abuts against the side end surface of the sealing core shaft 5 to fix the sealing core shaft 5.

[0024] In one or more embodiments, the first joint 11 has a step portion 16 , the inner wall of the step portion 16 abuts against the outer wall of the sliding core shaft 13 and is sealed by a sealing ring at the contact position.

[0025] In one or more embodiments, the sealing mandrel 5 is constructed as a cylindrical structure with a hollow interior, and in actual working conditions, the sealing mandrel 5 has a pipe column (not shown) inside, and the pipe column has fluid inside. Compared with the hydraulic anchor body 6, the sealing mandrel 5 is close to the interior of the self-locking hydraulic anchor 100, and part of the outer wall of the sealing mandrel 5 abuts against part of the inner wall of the hydraulic anchor body 6, and O-rings are provided at both ends of the outer wall of the sealing mandrel 5 in contact with the hydraulic anchor body 6, so that the hydraulic anchor body 6 is isolated from the pipe column inside the sealing mandrel 5, and part of the outer wall of the sealing mandrel 5 does not contact part of the inner wall of the hydraulic anchor body 6 to form a closed cavity s.

[0026] In one or more embodiments, the one-way valve a is arranged near the sliding core shaft 13, and includes a valve core 9 and a valve seat 8, wherein the valve seat 8 is arranged inside the hydraulic anchor body 6, the valve core 9 protrudes from the end surface of the hydraulic anchor body 6, the valve core 9 can contact with the sliding core shaft 13 and separate from the valve seat 8 under the action of its thrust, and can contact the valve seat 8 again after the thrust of the sliding core shaft 13 is reduced or stopped. When the valve core 9 is separated from the valve seat 8, the one-way valve a fails, so that the fluid can be allowed to flow in from the first end of the one-way valve a and flow out from the second end of the one-way valve a, and the fluid can also be allowed to flow in from the second end of the one-way valve a and flow out from the first end of the one-way valve a. The first end of the one-way valve a is connected to the closed cavity s, and the second end of the one-way valve a is connected to the pipe column inside the sealing core shaft 5 through the slot 10. The slot 10 is opened on the sealing core shaft 5 and is close to the one-way valve a. The slot 10 can connect the second end of the one-way valve a with the pipe column inside the sealing core shaft 5. When the valve core 9 contacts the valve seat 8 again, the one-way valve a only allows one-way flow.

[0027] For example, when the valve core 9 is separated from the valve seat 8, the one-way valve a fails, and the fluid in the inner pipe column of the sealing core shaft 5 can flow to the second end of the one-way valve a through the notch 10, and flow out from the first end of the one-way valve a and enter the closed cavity s, and the fluid in the closed cavity s can flow to the first end of the one-way valve a, and flow to the inner pipe column of the sealing core shaft 5 through the second end of the one-way valve a and the notch 10. When the valve core 9 contacts the valve seat 8 again, the one-way valve a only allows one-way flow, that is, the fluid can only flow in from the second end of the one-way valve a and flow out from the first end of the one-way valve a. For example, the fluid in the inner pipe column of the sealing core shaft 5 flows to the second end of the one-way valve a through the notch 10, and flows out from the first end of the one-way valve a and enter the closed cavity s.

[0028] In one or more embodiments, the first side end face of the sliding core shaft 13 can be pressed into contact with the hydraulic anchor body 6, and an elastic member 11 is provided on the second side end face of the sliding core shaft 13 opposite to the first side end face. The elastic member 11 is located in a space surrounded by the side end face of the step portion 16 of the first joint 12, the inner wall of the first joint 12 and the second side end face of the sliding core shaft 13, and the elastic member 11 is also connected to the side end face of the step portion 16.

[0029] In the assembled state outside the well, the elastic member 11 is in a compressed state and the elastic member 11 pushes the sliding core shaft 13 to be in pressure contact with the hydraulic anchor body 6, the valve seat 8 is arranged inside the hydraulic anchor body 6 and the valve core 9 protrudes from the end surface of the hydraulic anchor body 6, and the elastic member 11 pushes the sliding core shaft 13 to be in pressure contact with the hydraulic anchor body 6, while the sliding core shaft 13 contacts and pushes the valve core 9, so that the valve core 9 leaves the valve seat 8, thereby making the one-way valve a invalid, and the fluid can freely pass through the one-way valve a in both directions.

[0030] In actual use, the self-locking hydraulic anchor 100 of the present invention is placed in the casing and lowered into the well. During this process, the elastic member 11 is in a compressed state and the elastic member 11 pushes the sliding core shaft 13 to press and contact with the hydraulic anchor body 6. Since the valve core 9 protrudes from the end surface of the hydraulic anchor body 6, the elastic member 11 pushes the sliding core shaft 13 to press and contact with the hydraulic anchor body 6. At the same time, the sliding core shaft 13 contacts and pushes the valve core 9, so that the valve core 9 leaves the valve seat 8, making the one-way valve a invalid, and the fluid in the inner pipe string of the sealing core shaft 5 can pass through the groove. The fluid in the sealed cavity s can also flow to the first end of the one-way valve a, and flow to the inner pipe column of the sealing core shaft 5 through the second end of the one-way valve a and the notch 10. When the pressure in the inner pipe column of the sealing core shaft 5 is greater than the pressure on the outside of the self-locking hydraulic anchor 100, the anchor claws of the hydraulic anchor body 6 extend and anchor on the casing under the action of the internal and external pressure difference. When the external pressure of the self-locking hydraulic anchor 100 is greater than the internal pressure of the sealing core shaft 5, the anchor claws are automatically recovered.

[0031] During the reservoir transformation, the upper tubular column exerts an "upward force" on the sliding core shaft 13 under the action of thermal expansion and contraction, so that the sliding core shaft 13 moves away from the hydraulic anchor body 6. After the sliding core shaft 13 moves a certain distance, the valve core 9 of the one-way valve a is released and reset to contact with the valve seat 8. The fluid can only flow in from the second end of the one-way valve a and flow out from the first end of the one-way valve a. That is, the fluid in the inner tubular column of the sealing core shaft 5 flows to the second end of the one-way valve a through the notch 10, flows out from the first end of the one-way valve a and enters the closed cavity s, and the closed cavity The liquid in s cannot flow out, thereby maintaining the pressure in the closed cavity s, so that the pressure inside the self-locking hydraulic anchor 100 is always greater than the pressure outside it, and the anchor claws of the hydraulic anchor body 6 are always in an extended state, that is, the anchor claws are locked, so that even if the construction pump pressure suddenly drops sharply, the pressure inside the sealing core shaft 5 also suddenly drops sharply, the pressure in the closed cavity s can still be maintained greater than the external pressure of the pipe string, and the hydraulic anchor claws still remain anchored on the casing, thereby avoiding the problem of hydraulic anchor claw failure caused by a sudden and sharp drop in construction pump pressure during reservoir transformation. After the reservoir transformation is completed, the wellbore temperature rises, and the "lifting force" applied by the upper pipe string of the hydraulic anchor to the sliding core shaft 13 disappears. Under the elastic force of the elastic member 11, the sliding core shaft 13 pushes the valve core 9 away from the valve seat 8, and the one-way valve a fails. The fluid in the internal pipe string of the sealing core shaft 5 can flow to the second end of the one-way valve a through the notch 10, and flow out from the first end of the one-way valve a and enter the closed cavity s; similarly, the fluid in the closed cavity s can also flow to the first end of the one-way valve a, and flow to the inside of the sealing core shaft 5 through the second end of the one-way valve a and the notch 10. When the pressure inside the sealing core shaft 5 is greater than the external pressure of the self-locking hydraulic anchor 100, the anchor claws of the hydraulic anchor body 6 extend and anchor on the casing under the action of the internal and external pressure difference; when the external pressure of the self-locking hydraulic anchor 100 is greater than the internal pressure of the sealing core shaft 5, the anchor claws are automatically retracted.

[0032] In one or more embodiments, the self-locking hydraulic anchor 100 described in the present invention also includes a double female joint 14 connected to the end of the sliding core shaft 13 away from the hydraulic anchor body 6, which is used to convert the flat male buckle into the required female buckle, thereby facilitating direct connection with the pipe column through tools.

[0033] In one or more embodiments, two groups of 120° evenly distributed anchor claws are installed on the hydraulic anchor body 6, each group includes 3 anchor claws, and the self-locking hydraulic anchor 100 can be anchored on the casing after the 6 anchor claws are extended. In this embodiment, the hydraulic anchor body includes two symmetrically distributed check valves a.

[0034] In one or more embodiments, the elastic member 11 may be a disc spring, and the pre-compression force of the disc spring is determined according to the completion string combination and actual working conditions, and is achieved by adjusting the specifications, combination method, and quantity of the disc spring.

[0035] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A self-locking hydraulic anchor, comprising: A hydraulic anchor body, a sliding mandrel capable of contacting the hydraulic anchor body, an elastic member connected to the sliding mandrel, a one-way valve, and a sealing mandrel, wherein the one-way valve comprises a valve seat disposed inside the hydraulic anchor body and a valve core capable of being separated from or in contact with the valve seat, A part of the outer wall of the sealing mandrel and a part of the inner wall of the hydraulic anchor body form a closed cavity, a first end of the one-way valve is communicated with the closed cavity, and a second end thereof is communicated with an inner pipe column of the sliding mandrel, The sliding core shaft can press and contact the hydraulic anchor body under the action of the elastic member and simultaneously push the valve core away from the valve seat, and can also move away from the hydraulic anchor body under the action of external force so that the valve core contacts the valve seat.

2. The self-locking hydraulic anchor according to claim 1, characterized in that: The valve core protrudes from the end surface of the hydraulic anchor body so that when the sliding core shaft is in pressure contact with the hydraulic anchor body, the sliding core shaft can contact the valve core to push the valve core away from the valve seat.

3. The self-locking hydraulic anchor according to claim 1, characterized in that: Relative to the hydraulic anchor body, the sealing core shaft is close to the interior of the self-locking hydraulic anchor, part of the outer wall of the sealing core shaft abuts against part of the inner wall of the hydraulic anchor body, and sealing rings are provided at both ends of the contact position, part of the outer wall of the sealing core shaft does not contact part of the inner wall of the hydraulic anchor body and forms the closed cavity.

4. The self-locking hydraulic anchor according to claim 1, characterized in that: It also includes a first joint disposed at the first end of the hydraulic anchor body, which has a step portion, the inner wall of the step portion abuts against the outer wall of the sliding core shaft and is sealed by a sealing ring at the contact position.

5. The self-locking hydraulic anchor according to claim 4, characterized in that: The first side end face of the sliding core shaft can be pressed into contact with the hydraulic anchor body, and the elastic member is connected to the second side end face of the sliding core shaft opposite to the first side end face. The elastic member is located in a space surrounded by the side end face of the step portion, the inner wall of the first joint and the second side end face of the sliding core shaft, and the elastic member is also connected to the side end face of the step portion.

6. The self-locking hydraulic anchor according to claim 1, characterized in that: The sealing core shaft is provided with a notch, and the second end of the one-way valve is communicated with the inner pipe column of the sliding core shaft through the notch.

7. The self-locking hydraulic anchor according to claim 4, characterized in that: It also includes a second joint arranged at the second end of the hydraulic anchor body, which has a step. The outer wall of the step abuts against the inner wall of the hydraulic anchor body and is sealed by a sealing ring at the contact position. The side end surface of the step also abuts against the side end surface of the sealing core shaft to fix the sealing core shaft.

8. The self-locking hydraulic anchor according to claim 1, characterized in that: The hydraulic anchor body has two groups of anchor claws evenly distributed at 120 degrees inside, which are used to anchor the self-locking hydraulic anchor on the casing.

9. The self-locking hydraulic anchor according to claim 1, characterized in that: The elastic member is a butterfly valve.

10. The self-locking hydraulic anchor according to claim 1, characterized in that: Also included is a double female joint connected to the end of the sliding mandrel away from the hydraulic anchor body, which is used to change a flat male buckle into a female buckle.

Images