Long-acting anchoring tool and method of use

Abstract

The application discloses a long-acting anchoring tool and method, which comprises an outer protection mechanism, an inner protection mechanism, a well washing mechanism and an anchoring mechanism, wherein the outer protection mechanism comprises a connecting sleeve, a protection cylinder, a sealing sleeve and a starting piston; the inner protection mechanism comprises a pressure transmission piston, an outer cylinder and a lower central pipe, and protection liquid is placed in the inner protection mechanism; the well washing mechanism comprises a well washing sleeve, a well washing spring, an upper piston, a lower piston and a sealing element; and the anchoring mechanism comprises a main body, a spring, an anchor claw and a pressing sheet. The application can effectively improve the service life of the anchoring tool and the reliability of recovery, further reduce the risk of later inspection and replacement, prolong the service life of a matched pipe column, and has important significance for further improving fine separate injection levels of water injection development in old oil fields.

Description

Technical Field

[0001] The invention relates to an underground supporting tool for oil production in the oil field, in particular to a long-acting anchoring tool for stratified water injection and a use method thereof. Background Art

[0002] When the operating conditions of an injection well change, the injection string can creep under the influence of pressure and temperature, severely impacting or even destroying the downhole performance of the packer system and significantly reducing the life of the stratified water injection string. To combat this creep, anchoring tools are commonly used in injection strings to reduce the effects of this creep. Anchoring tools typically use hydraulic pressure to force anchor claws into the inner wall of the casing, achieving a certain anchoring force. However, after long-term use in the well, corrosion, scaling, and other factors can prevent the anchor claws from being properly retrieved during later inspections and replacements, leading to major repairs that consume significant manpower, material resources, and time, resulting in significant economic losses.

[0003] In the prior art, CN206845127U discloses a double-acting anchoring tool for well washing and isolation, including a sand control pipe, a casing, an upper coupling, a sealing rubber sleeve, a rubber sleeve core tube, a rubber sleeve telescopic body, a tapered hoop, a tooth, a sliding sleeve, an expansion block, a central guide tube, and a lower coupling. The tool is characterized in that: the upper coupling is evenly distributed with well washing holes, a valve seat is provided on the central guide tube, a single valve is provided in the inner cavity of the tapered hoop on the valve seat, an oil outlet hole is provided on the upper part of the tapered hoop, a positioning pin is provided on the lower part of the rubber sleeve core tube and cooperates with the keyway on the rubber sleeve telescopic body, and shear nail holes are provided on the circumference of the rubber sleeve telescopic body, and the protective shear nails are threadedly matched with the shear nail holes of the rubber sleeve telescopic body.

[0004] CN210033342U discloses a water injection well pipe string anchoring device, including a center pipe, a cava mechanism, and a friction reversing mechanism. The cava mechanism and the friction reversing mechanism are both mounted on the outside of the center pipe, wherein the upper end of the friction reversing mechanism is connected to the lower end of the cava mechanism. The friction reversing mechanism includes a friction reversing sleeve, a friction reversing plate, and a leaf spring. The upper end of the friction reversing sleeve is connected to the cava mechanism. The friction reversing sleeve is provided with an axial reversing track. The reversing track includes parallel short tracks and long tracks. The upper end of the short track is connected to the upper end of the long track through a transition track. A radial reversing pin is installed on the outer wall of the center pipe, and the reversing pin runs in the reversing track. The utility model is that, firstly, for high-pressure deep wells and large pressure difference wells, after anchoring, the pipe string above the anchoring device will not creep; secondly, after anchoring, the anchoring force will not be automatically eliminated as the ground well is shut down, thereby playing a better anchoring role.

[0005] CN113153208A discloses a hydraulic expansion packer capable of flushing a well. An anchor claw is installed in the anchor claw hole of the upper joint, an open lock ring is installed in the push sleeve, and the open lock ring is installed on the one-way external teeth on the outer wall of the inner tube. A sealing force generating mechanism is installed at the lower part of the inner tube, and the lower part of the push sleeve is connected to the upper part of the sealing force generating mechanism. The lower part of the push sleeve has a well flushing water outlet, and the upper part of the push sleeve has a vertical groove. The rubber sleeve joint is vulcanized into one piece with the rubber sleeve, and the sealing seat is connected to the rubber sleeve joint. The rubber sleeve joint, The rubber sleeve is sleeved on the outside of the inner tube, the well washing piston is sleeved on the inner tube, the lower part of the well washing piston cooperates with the upper part of the sealing seat for sealing, the upper part of the inner tube is connected to the lower thread of the upper joint, the clamping ring is installed in the upper part of the well washing sleeve, the well washing sleeve is sleeved on the upper joint and the outside of the well washing piston, the upper part of the inner tube is provided with a pressure transmission hole, the lower part of the well washing sleeve is provided with a well washing water inlet, the upper part of the well washing sleeve is suspended on the lower shoulder of the upper joint, the anchor claw platform of the anchor claw corresponds to the anchor claw groove of the well washing sleeve, and the shear nails are unsealed to connect the well washing sleeve to the upper joint.

[0006] CN113417595A discloses an anchored packer, comprising an upper joint, an upper retaining cap, a well-washing sleeve, a deblocking shear pin, a balancing piston, a control piston, a well-washing piston, an upper outer central tube, an inner central tube, a lower outer central tube, a first-stage setting piston, a connecting sleeve, a locking ring seat, a cylinder sleeve, a second-stage setting piston, a central tube locking block, a setting shear pin, a cone locking block, an upper cone, a slip sleeve, a lower cone, an anti-torsion key sleeve, and a lower joint. The upper joint and the inner central tube are threadedly connected; the upper retaining cap is threadedly connected to the well-washing sleeve and slidably mounted on the outside of the upper joint; the well-washing sleeve and the upper joint are connected by deblocking shear pins; a balancing piston and a control piston are mounted in the annular space between the well-washing sleeve and the inner central tube; a well-washing piston is mounted in the annular space between the well-washing sleeve and the control piston; and the well-washing sleeve is threadedly connected to the upper outer central tube. The invention has comprehensive functions, realizing functions such as well washing, double-piston sealing and safety control, anchoring and anchoring assistance, while ensuring sufficient internal diameter.

[0007] However, the above technology is only applied to oil wells and is not suitable for water injection wells. At the same time, the above technical means are mainly for achieving the functions of anchoring, isolation and well washing, but do not involve the long-term performance of the tool and the performance of subsequent safety inspection and replacement. Summary of the Invention

[0008] In order to overcome the above-mentioned deficiencies of conventional anchoring tools, the present application proposes a long-lasting anchoring tool and a method of use.

[0009] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions. The long-term anchoring tool mainly consists of four parts: an external protection mechanism, an internal protection mechanism, a well washing mechanism and an anchoring mechanism. Among them, the external protection mechanism is mainly composed of a connecting sleeve, a protection cylinder, a sealing sleeve and a starting piston, etc. The starting piston is controlled by a shear pin, which ensures the safety of the tool when entering the well; after the protection cylinder is released, it can avoid the corrosion, scaling and mechanical deposition of the oil casing annulus fluid on the anchoring mechanism, extend the service life of the anchoring tool and reduce the risk of later inspection and replacement; the internal protection mechanism is mainly composed of a pressure transmission piston, an outer cylinder and a lower center pipe, etc., in which a protective liquid is placed inside. On the one hand, the pressure transmission piston is controlled by the shear pin to ensure that the anchoring mechanism does not move when going down the well; on the other hand, the internal protection liquid is separated from the fluid injected into the oil pipe, which can avoid the corrosion of the anchoring mechanism by the fluid injected into the oil pipe, The impact of scaling, further extending the tool life and reducing the safety of later inspections and replacements; the well washing mechanism and the anchoring mechanism, the well washing mechanism is mainly composed of the well washing casing, well washing spring, upper piston, lower piston and seals, and the anchoring mechanism is mainly composed of the main body, spring, anchor claw and pressing piece; after the protective cylinder is released, when the oil pressure is less than or equal to the casing pressure, the well washing fluid can effectively pass through the protective cylinder, and the backwashing operation of the matching tubing can be realized. At this time, the anchor claw is in a retracted state, effectively reducing the effects of the well washing fluid on the deposition, corrosion, scaling, etc. of the anchoring mechanism; when the oil pressure is greater than the casing pressure, the well washing mechanism channel is closed, the anchoring mechanism realizes bidirectional anchoring, and the protective cylinder realizes protection of the anchoring mechanism.

[0010] The specific technical solutions are:

[0011] A long-term anchoring tool, comprising: an outer protection mechanism, an inner protection mechanism, a well washing mechanism and an anchoring mechanism.

[0012] Wherein, the outer protection mechanism includes a connecting sleeve, a protection cylinder, a sealing sleeve and a starting piston;

[0013] The inner protection mechanism comprises a pressure-transmitting piston, an outer cylinder and a lower central tube, and a protection liquid is placed inside the inner protection mechanism;

[0014] The well washing mechanism includes a well washing sleeve, a well washing spring, an upper piston, a lower piston and a sealing element; the anchoring mechanism includes a main body, a spring, an anchor claw and a pressing piece.

[0015] Preferably, the start piston is controlled by shear pins.

[0016] Preferably, the upper portion of the sealing sleeve is threadedly connected to the connecting sleeve.

[0017] Preferably, a sealing cylinder is provided between the connecting sleeve and the starting piston sealing cylinder.

[0018] Preferably, the pressure-transmitting piston is installed in the annulus between the outer tube and the lower central tube.

[0019] Preferably, the pressure-transmitting piston and the main body form a closed space, and a protective liquid is contained in the closed space.

[0020] The method for using the above-mentioned long-term anchoring tool includes the following steps:

[0021] Lowering into the well: Connect the long-term anchoring tool to the tool string and lower it into the well to ensure the tool is safely lowered into the well.

[0022] Water injection: The injected fluid passes through the bridge channel between the upper center tube and the sealing sleeve, pushing the starting piston to cut the shear pins and move them down to the limit pin, releasing the sealing cylinder. The sealing cylinder, under the action of its own elastic force, clings to the casing to form a protective layer. At the same time, the injected fluid pushes the hydraulic piston, cutting the shear pins and moving them down, squeezing the protective liquid inside, so that the anchor claw overcomes the elastic force of the spring and the pressure plate and clings to the casing, achieving two-way anchoring.

[0023] Backwashing: When stopping injection or backwashing, the anchor claw is retracted under the action of the spring force and the pressure plate, and the anchoring state is released; when the casing well-washing hydraulic pressure reaches a certain value, the lower piston and the upper piston are pushed to overcome the elastic force of the well-washing spring and move upward, the well-washing channel is opened, and the well-washing fluid flows out through the bridge channel between the upper center pipe and the sealing sleeve.

[0024] Compared with the existing technology, the long-term anchoring tool of this invention has the following advantages:

[0025] 1. The external and internal protection mechanisms can effectively prevent the corrosion and scaling of the anchoring mechanism by the fluid in the annular space of the casing and the impact of the sediment in the annular space of the casing and the anchoring tool on the anchoring mechanism. On the other hand, the external and internal protection mechanisms can prevent the fluid injected into the tubing from contacting the inside of the anchoring mechanism, thus avoiding the internal corrosion and scaling caused by the injected fluid.

[0026] 2. The outer protection mechanism adopts a leather cup structure design, which can protect the anchoring mechanism without increasing the risk of later inspection and replacement. At the same time, it adopts a bridge structure design and is relatively independent of the well washing mechanism. The inner protection mechanism adopts a hydraulic transmission structure design, which can realize the protection of the anchoring mechanism with protective fluid for corrosion and scale prevention, and can also realize anchoring and unanchoring of the anchoring mechanism through hydraulic transmission.

[0027] 3. The well-washing mechanism is coupled with the anchoring mechanism. When the oil pressure is less than or equal to the casing pressure, the well-washing fluid can effectively pass through the protective tube, realizing the backwash operation of the matching tubing string. At this time, the anchor claw is in a retracted state, effectively reducing the effects of the well-washing fluid on the anchoring mechanism such as deposition, corrosion, and scaling. When the oil pressure is greater than the casing pressure, the well-washing mechanism channel is closed, the anchoring mechanism achieves bidirectional anchoring, and the protective tube protects the anchoring mechanism.

[0028] This invention can effectively improve the service life and recovery reliability of anchoring tools, further reduce the risk of later inspection and replacement, thereby extending the service life of the matching pipe string, and is of great significance for further improving the level of fine injection in water injection development of old oil fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the long-acting anchoring tool of the present invention.

[0030] Figure 2 This is the well washing mechanism and external protection mechanism of the long-term anchoring tool of the present invention.

[0031] Figure 3 This is the internal protection mechanism and anchoring mechanism in the long-term anchoring tool of the present invention.

[0032] In the figure: 1—upper connector; 2—well flushing sleeve; 3—well flushing spring; 4—upper center tube; 5—upper piston; 6—lower piston; 7—sealing element; 8—connecting sleeve; 9—sealing cylinder; 10—sealing sleeve; 11—starting piston; 12—limiting pin; 13—pressure transmitting piston; 14—outer cylinder; 15—lower center tube; 16—main body; 17—spring; 18—anchor claw; 19—pressing piece; 20—lower connector. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Example 1:

[0035] See attached Figure 1 A water injection well uses the long-term anchoring tool described in the present invention. In this embodiment, the long-term anchoring tool primarily includes an upper connector 1, a well-washing sleeve 2, a well-washing spring 3, an upper central pipe 4, an upper piston 5, a lower piston 6, a seal 7, a connecting sleeve 8, a sealing sleeve 9, a sealing sleeve 10, a starting piston 11, a limit pin 12, a pressure-transmitting piston 13, an outer sleeve 14, a lower central pipe 15, a main body 16, a spring 17, an anchor claw 18, a pressure piece 19, and a lower connector 20.

[0036] Among them, the upper joint 1 is respectively connected to the well washing sleeve 2 and the upper center pipe 4 by threads; the well washing spring 3, the upper piston 5, and the lower piston 6 are placed in the annulus formed by the well washing sleeve 2 and the upper center pipe 4; the seal 7 is installed on the lower piston 6; the outside of the connecting sleeve 8 is connected to the well washing sleeve 2 by threads; the sealing cylinder 9 is installed between the connecting sleeve 8 and the starting piston 11; the upper part of the sealing sleeve 10 is connected to the connecting sleeve 8 by threads, the bridge part is welded to the upper center pipe 4, and the lower part is installed with a limit pin 12; the pressure transmitting piston 13 is installed in the annulus between the outer cylinder 14 and the lower center pipe 15, and a certain amount of protective liquid is contained in the enclosed space formed with the main body 16; the outer cylinder 14 is respectively connected to the sealing sleeve 10 and the main body 16 by threads; the spring 17 is placed between the anchor claw 18 and the pressing plate 19, and the pressing plate 19 is connected to the main body 16 by a pin.

[0037] Example 2:

[0038] Using the long-term anchoring tool as in Implementation 1, the following steps are mainly used:

[0039] Lowering into the well: Connect the long-term anchoring tool to the tool string and lower it into the well. Due to the shear control, the starting piston 11 and the pressure transmission piston 13 cannot move, ensuring the safe entry of the tool into the well.

[0040] Water injection: see attached Figure 2 During water injection, when the oil pressure rises to a certain value, the injected fluid passes through the bridge channel between the upper center tube 4 and the sealing sleeve 10, pushing the starting piston 11 to cut the shear pins and move down to the limit pin 12, releasing the sealing cylinder 9. The sealing cylinder 9 is tightly attached to the casing under its own elastic force to form protection; at the same time, the injected fluid pushes the hydraulic piston 13, shears the shear pins and moves downward, squeezing the internal protective liquid, so that the anchor claw 18 overcomes the elastic force of the spring 17 and the pressing plate 19 and sticks to the casing, realizing bidirectional anchoring; during this process, the backwash well channel of the well washing mechanism is always closed.

[0041] Backwash well: see attached Figure 3 When injection is stopped or the well is backwashed, the anchor claw 18 is retracted under the action of the spring force 17 and the pressure plate 19, and the anchor state is released; when the casing well washing hydraulic pressure reaches a certain value, the lower piston 6 and the upper piston 5 are pushed to overcome the elastic force of the well washing spring 3 and move upward, the well washing channel is opened, and the well washing fluid flows out through the bridge channel between the upper center pipe 4 and the sealing sleeve 10.

[0042] In the long-lasting anchoring tool described in this embodiment,

[0043] 1. The external and internal protection mechanisms can effectively prevent the corrosion and scaling of the anchoring mechanism by the fluid in the annular space of the casing and the impact of the sediment in the annular space of the casing and the anchoring tool on the anchoring mechanism. On the other hand, the external and internal protection mechanisms can prevent the fluid injected into the tubing from contacting the inside of the anchoring mechanism, thus avoiding the internal corrosion and scaling caused by the injected fluid.

[0044] 2. The outer protection mechanism adopts a leather cup structure design, which can protect the anchoring mechanism without increasing the risk of later inspection and replacement. The inner protection mechanism adopts a hydraulic transmission structure design, which can realize the protection of the anchoring mechanism with protective liquid to prevent corrosion and scale, and can also realize anchoring and unanchoring of the anchoring mechanism through hydraulic transmission.

[0045] 3. The well-washing mechanism is coupled with the anchoring mechanism. When the oil pressure is less than or equal to the casing pressure, the well-washing fluid can effectively pass through the protective tube, realizing the backwash operation of the matching tubing. At this time, the anchor claw is in a retracted state, effectively reducing the effects of the well-washing fluid on the anchoring mechanism such as deposition, corrosion, and scaling. When the oil pressure is greater than the casing pressure, the well-washing mechanism channel is closed, the anchoring mechanism achieves bidirectional anchoring, and the protective tube protects the anchoring mechanism.

[0046] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A long-term anchoring tool, characterized in that include: External protection mechanism, internal protection mechanism, well washing mechanism and anchoring mechanism, Wherein, the outer protection mechanism includes a connecting sleeve, a protection cylinder, a sealing sleeve and a starting piston; The inner protection mechanism comprises a pressure-transmitting piston, an outer cylinder and a lower central tube, and a protection liquid is placed inside the inner protection mechanism; The well washing mechanism includes a well washing sleeve, a well washing spring, an upper piston, a lower piston and a seal, and the anchoring mechanism includes a main body, a spring, an anchor claw and a pressing piece; It also includes an upper joint, which is connected to the well washing sleeve and the upper center pipe respectively; the well washing spring, the upper piston and the lower piston are placed in the annulus formed by the well washing sleeve and the upper center pipe; and the sealing member is installed on the lower piston; The outside of the connecting sleeve is connected to the well washing sleeve; the sealing cylinder is installed between the connecting sleeve and the starting piston; the upper part of the sealing sleeve is connected to the connecting sleeve, and the sealing sleeve is provided with a bridge channel connected to the upper center pipe, and a limit pin is installed on the lower part of the sealing sleeve; the bridge channel is connected to the inside of the starting piston, and the injected fluid passes through the bridge channel between the upper center pipe and the sealing sleeve, pushing the starting piston to cut the shear pin and move down to the limit pin; The pressure-transmitting piston is installed in the annular space between the outer tube and the lower center tube, and the outer tube is connected with the sealing sleeve and the main body respectively.

2. The long-lasting anchoring tool according to claim 1, characterized in that: The starting piston is controlled by shear pins.

3. The long-lasting anchoring tool according to claim 1, characterized in that: The upper portion of the sealing sleeve is threadedly connected to the connecting sleeve.

4. The long-lasting anchoring tool according to claim 1, characterized in that: A sealing cylinder is provided between the connecting sleeve and the starting piston.

5. The long-lasting anchoring tool according to claim 1, characterized in that: The pressure-transmitting piston is installed in the annulus between the outer cylinder and the lower central tube.

6. The long-lasting anchoring tool according to claim 5, characterized in that: The pressure-transmitting piston and the main body form a closed space, and a protective liquid is contained in the closed space.

7. A method for using the long-lasting anchoring tool according to any one of claims 1 to 6, characterized in that The following steps are involved: Lowering the tool into the well: Connect the long-term anchoring tool to the tool string and lower it into the well to ensure the tool is safely lowered into the well; Water injection: The injected fluid passes through the bridge channel between the upper center tube and the sealing sleeve, pushing the starting piston to cut the shear pins and move them down to the limit pin, releasing the sealing cylinder. The sealing cylinder, under the action of its own elastic force, clings to the casing to form a protective layer. At the same time, the injected fluid pushes the hydraulic piston, cutting the shear pins and moving them down, squeezing the protective liquid inside, so that the anchor claw overcomes the elastic force of the spring and the pressure plate and clings to the casing, achieving two-way anchoring. Backwashing: When stopping injection or backwashing, the anchor claw is retracted under the action of the spring force and the pressure plate, and the anchoring state is released; when the casing well-washing hydraulic pressure reaches a certain value, the lower piston and the upper piston are pushed to overcome the elastic force of the well-washing spring and move upward, the well-washing channel is opened, and the well-washing fluid flows out through the bridge channel between the upper center pipe and the sealing sleeve.

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