A type of well salvage tool

Abstract

This utility model discloses a downhole fishing tool, including a guide cylinder and a claw assembly located inside the guide cylinder. The upper section of the guide cylinder is equipped with a spring assembly, and the lower section is equipped with a claw assembly. The lower end of the spring assembly abuts against the upper end of the claw assembly. The lower inner wall of the guide cylinder has an inwardly inclined guide surface, which corresponds to the elastic claw of the claw assembly. This utility model has a simple structure, is easy to operate, easy to maintain and repair, has good fishing performance, can adapt well to narrow working spaces, effectively avoids secondary damage to the instrument, and has both self-locking and unlocking functions. It is suitable for various instrument compartments or other downhole equipment that can be connected to a fishing head.

Description

Technical Field

[0001] This utility model relates to the field of well fishing, specifically to a well fishing tool. Background Technology

[0002] In directional drilling and geosteering operations, the non-magnetic drill collar is a core component housing the MWD (Maneuvering Wind Deployment) critical instrument compartment. During tripping in or out of the well, instrument replacement, or in case of accidents, the instrument string may become stuck inside the non-magnetic drill collar. During retrieval operations, the working space is limited, and the lighting and visibility are extremely poor. The instruments inside are usually precise and expensive, and rough retrieval methods can easily cause secondary damage, rendering the instruments completely unusable.

[0003] For the retrieval of the internal MWD of a non-magnetic drill collar, conventional retrieval tools are almost helpless: mechanical claw retrieval lacks external gripping points and requires entry into the narrow inner diameter, limiting the opening range and force of the claw; strong magnetic retrieval devices are rendered ineffective by the dual limitations of a non-magnetic environment and the non-magnetic materials of the instrument.

[0004] Patent No. 2016202095358 discloses an oilfield downhole retrieval cylinder, including a retrieval rod. A power box is installed at the bottom of the retrieval rod, and a drive motor is installed in the power box via a fixed seat. The output shaft of the drive motor is connected to a rotating sleeve via a coupling. A limit sleeve is installed at the bottom of the power box, and the rotating sleeve is inserted into the limit sleeve. A connecting cylinder is installed at the bottom of the limit sleeve. By controlling the rotation of the motor, the transmission component pulls the retrieval claw to perform a grasping action, which has a good grasping effect on irregular objects. However, it does not have a self-locking function, and the retrieval effect on instruments in a jammed state is poor. It is not suitable for narrow working spaces, and it is also easy to cause secondary damage to the instrument in the rotating state.

[0005] Patent No. 2023217148373 discloses a downhole choke retriever tool, including an upper connecting kit and a lower connecting kit located at the bottom of the upper connecting kit. The upper connecting kit includes a connector that connects to the choke retriever tool and a connecting cylinder located at the bottom of the connector. The lower connecting kit includes a snap-fit ​​sleeve that connects to the top of the choke, with several claw assemblies arranged in a ring array on the inner wall of the snap-fit ​​sleeve. This downhole choke retriever tool relies solely on the elastic expansion of the claws to connect and fix the choke, and also lacks a self-locking function. Furthermore, the key point of this invention is that when the choke is obstructed by the wellbore wall and cannot be retrieved, the interaction between the piston head and the pressing plate allows the claws to expand and protectively separate from the retrieval head of the retriever tool, preventing forced retrieval and potential downhole accidents. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned technical problems and provide a downhole retrieval tool that is simple in structure, easy to operate, can adapt well to narrow working spaces, effectively avoids secondary damage to the instrument, and has both self-locking and unlocking functions.

[0007] The technical solution includes a guide cylinder and a claw assembly located inside the guide cylinder. The upper section of the guide cylinder is provided with a spring assembly, and the lower section is provided with a claw assembly. The lower end of the spring assembly abuts against the upper end of the claw assembly. The lower end of the guide cylinder has an inwardly inclined guide surface, which corresponds to the elastic hook of the claw assembly.

[0008] To address the problems existing in the background technology, this application utilizes a spring assembly to apply force to the claw assembly, which, in conjunction with the guide surface at the lower end of the guide cylinder, allows the elastic claw of the claw assembly to overcome the force of the spring assembly and open along the guide surface when subjected to an upward force, enabling the retrieval head to be smoothly inserted. Then, under the force of the spring assembly, the elastic claw tightens downward along the guide surface, tightly holding the retrieval head. During the lifting process, the instrument connected to the retrieval head, under the action of gravity, will cause the elastic claw to press downward against the guide surface, maintaining a locked state and achieving the purpose of self-locking and preventing detachment.

[0009] Furthermore, it also includes a limiting and unlocking component, which includes a sliding sleeve fitted outside the guide cylinder. The guide cylinder has two centrally symmetrical positioning grooves. The upper section of the claw assembly has a horizontal pin, and both ends of the horizontal pin pass through the corresponding positioning grooves and connect to the sliding sleeve. The limiting and unlocking component restricts the axial movement of the claw assembly within the positioning grooves, preventing the claw assembly from disengaging.

[0010] The positioning groove is an L-shaped groove, consisting of an axial groove arranged along the axial direction and a circumferential groove arranged along the circumferential direction. The axial groove is used to limit the range of movement of the claw assembly along the axial direction, and the circumferential groove is used to limit the rotation distance of the claw assembly. A universal cross pin links the sliding sleeve with the claw assembly via the positioning groove. After the retrieval action is completed and the instrument is lifted, the retrieval head can be pushed, and then the sliding sleeve can be rotated to move the cross pin through the axial groove into the circumferential groove and lock it in place. Finally, the elastic claw unfolds and remains fixed, releasing the self-locking state, thus allowing the retrieval head to be easily withdrawn from the elastic claw.

[0011] The two ends of the cross pin are connected to the sliding sleeve by screw threads, which facilitates disassembly and maintenance;

[0012] The claw assembly includes an upper claw seat and a lower claw with multiple elastic hooks.

[0013] The top of the card holder is provided with a lower spring seat for mounting the spring assembly.

[0014] The spring assembly includes an upper end head mounted on the upper end of the guide cylinder and a compression spring located between the upper end head and the claw assembly.

[0015] The lower end of the upper end is provided with an upper spring seat.

[0016] The lower end of the upper end head is threadedly connected to the guide cylinder, and the upper end is provided with a connecting section that can be connected to the extension rod. By connecting the extension rod, the distance between the wellhead and the retrieval head can be compensated.

[0017] The guide cylinder has multiple drainage holes to facilitate the discharge of mud from the guide cylinder during retrieval.

[0018] Beneficial effects:

[0019] This utility model has a simple structure, is easy to operate, easy to maintain and repair, has a good retrieval effect, can adapt well to narrow working spaces, effectively avoids secondary damage to instruments, and has both self-locking and unlocking functions. It is suitable for various instrument compartments or other downhole equipment that can be connected to retrieval heads. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention in the locked state.

[0021] Figure 2 This is a schematic diagram of the structure of the present invention in the unlocked state.

[0022] Figure 3 This is an external view of the guide cylinder.

[0023] Figure 4 This is a schematic diagram of the claw assembly.

[0024] Figure 5 This is a diagram showing the usage state of this utility model.

[0025] Among them, 1-guide cylinder, 1.1-guide surface, 2-spring assembly, 2.1-upper end head, 2.2-compression spring, 2.3-upper spring seat, 2.4-connecting section, 3-sliding sleeve, 4-claw assembly, 4.1-claw seat, 4.2-elastic claw, 4.3-lower spring seat, 5-horizontal pin, 6-screw, 7-drain hole, 8-positioning groove, 8.1-axial groove, 8.2-circumferential groove, 9-extension rod, 10-retrieval head, 11-non-magnetic drill collar. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, wherein the drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the present invention. However, those skilled in the art should understand that the following embodiments are not the only limitation on the technical solution of the present invention, and any equivalent transformations or modifications made under the spirit and essence of the technical solution of the present invention should be considered as falling within the protection scope of the present invention.

[0027] See Figure 1 The technical solution includes a guide cylinder 1 and a claw assembly 4 located inside the guide cylinder 1. The upper section of the guide cylinder 1 is provided with a spring assembly 2, and the lower section is provided with a claw assembly 4. The spring assembly 2 includes an upper end head 2.1 installed at the upper end of the guide cylinder 1 and a compression spring 2.2 located between the upper end head 2.1 and the claw assembly 4. The lower end of the upper end head 2.1 is provided with an upper spring seat 2.3.

[0028] See Figure 4 The claw assembly 4 includes an upper claw seat 4.1 and a plurality of elastic claws 4.2 in the lower section; the top of the claw seat 4.1 is provided with a lower spring seat 4.3. The upper end of the compression spring 2.2 abuts against the upper spring seat 2.3, and the lower end abuts against the lower spring seat 4.3.

[0029] The lower inner wall of the guide cylinder 1 has an inwardly inclined guide surface 1.1, which corresponds to the elastic claw 4.2 of the claw assembly 4. The minimum inner diameter of the outlet formed by the guide surface 1.1 should be greater than the maximum outer diameter of the retrieval head 10 and less than the maximum outer diameter of the elastic claw 4.2 in the retracted state. This ensures that the retrieval head 10 can be smoothly inserted into the guide cylinder 1, while also preventing the elastic claw 4.2 from being dislodged from the guide cylinder 1 under the force of the compression spring 2.2.

[0030] Preferably, the elastic claw 4.2 can be made of 65Mn material with high strength and good elasticity.

[0031] See Figure 1 It also includes a limit unlocking component, which includes a sliding sleeve 3 fitted outside the guide cylinder 1. The guide cylinder 1 is provided with two positioning grooves 8 symmetrically arranged along the center of the guide cylinder. A horizontal pin 5 is inserted into the upper section of the card seat 4.1. The two ends of the horizontal pin 5 pass through the corresponding positioning grooves 8 and are threadedly connected to the sliding sleeve 3 by screws 6.

[0032] The positioning groove 8 is an L-shaped groove, comprising an axial groove 8.1 arranged along the axial direction and a circumferential groove 8.2 arranged along the circumferential direction, with the upper end of the axial groove 8.1 connected to the circumferential groove 8.2. The axial groove 8.1 is used to limit the range of movement of the chuck assembly 4 along the axial direction, and the circumferential groove 8.2 is used to limit the distance of rotation of the limiting chuck assembly 4.

[0033] The lower end of the upper end 2.1 is threadedly connected to the guide cylinder 1, and the upper end is provided with a connecting section 2.4 that can be connected to the extension rod 9. By connecting the extension rod 9, the length of the distance from the wellhead to the retrieval head 10 can be compensated.

[0034] The guide cylinder 1 has multiple drainage holes 7 to facilitate the discharge of mud from the guide cylinder 1 during retrieval.

[0035] The working principle of this invention is described below using the example of internal retrieval from a non-magnetic drill collar:

[0036] Before the salvage operation, the elastic claws 4.2 are located at the bottom of the guide surface 1.1 of the guide cylinder 1 under the action of the compression spring 2.3, and the multiple elastic claws 4.2 are in a retracted state under the guidance of the guide surface 1.1 of the guide cylinder 1.

[0037] When a salvage operation is required, firstly, slowly lower the salvage tool of this utility model along the center of the non-magnetic drill collar 11 until the head of the salvage head 10 passes upward from the bottom of the guide cylinder 1 and contacts the lower end of the retracted elastic claw 4.2; at this time, press down on the salvage tool to make the claw assembly 4 move upward against the force of the compression spring 2.2, and the elastic claw 4.2 gradually unfolds along the guide surface 1.1 under its own outward elastic force, so that the salvage head 10 can be fully inserted into the space enclosed by the elastic claw 4.2; after the salvage head 10 is fully inserted, the claw assembly 4 moves downward as a whole under the action of elastic force, and the lower end of the elastic claw 4.2 always keeps in contact with the guide surface 1.1 and slides downward, then retracts again, so that the multiple elastic claws 4.2 firmly hold the salvage head 10. Furthermore, since the lower edge of the conical step of the retrieval head 10 also remains in contact with the inner side of the elastic claw 4.2, during the lifting process, under the gravity of the instrument connected to the retrieval head 10, the elastic claw 4.2 remains in contact with the guide surface 1.1. Under the action of the guide surface 1.1, it contracts tighter and tighter, forming a self-locking mechanism to prevent the retrieval head 10 from coming off. When the claw assembly 4 moves up or down along the guide cylinder 1, it is limited in the axial groove 8.1 of the positioning groove 8 by the transverse pin 5, and simultaneously drives the sliding sleeve 3 to move synchronously.

[0038] After the salvage operation is completed and the instrument is lifted out, gently push the salvage head 10 towards the upper end 2.1 on the ground. While keeping the guide cylinder 1 stationary, lift the sliding sleeve 3 upwards so that the transverse lock 5 moves to the upper end of the axial groove 8.1. Then rotate the sliding sleeve 3 to one side of the circumferential groove 8.2 so that the transverse pin 5 moves into the circumferential groove 8.2 and locks in place. At this time, the elastic claw 4.2 moves upwards to separate from the guide surface 1.1 of the guide cylinder 1. The elastic claw 4.2 undergoes elastic deformation and returns to its unfolded state and remains there. At this time, the salvage head 10 can be easily removed.

[0039] Before the retrieval operation is required again, rotate the sliding sleeve 3 to the other side to move the transverse pin 5 to the upper end of the axial groove 8.1. Under the action of the compression spring 2.2, the transverse lock 5 moves along the axial groove 8.1 towards the lower end of the guide cylinder 1. At the same time, the claw assembly 4 is forced to move downward, causing multiple elastic claws 4.2 to begin to retract under the guidance of the guide surface 1.1 of the guide cylinder 1, until the state before the aforementioned retrieval operation is reached.

[0040] This utility model of retrieval tool is applicable to various instruments or equipment that can be connected to retrieval heads.

[0041] The above content is only for illustrating the technical concept of this utility model and should not be construed as limiting the scope of protection of this utility model. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this utility model.

Claims

1. A downhole fishing tool comprising a guide cylinder and a jaw assembly located within the guide cylinder, characterized in that, The upper section of the guide cylinder is provided with a spring assembly, and the lower section is provided with a claw assembly. The lower end of the spring assembly abuts against the upper end of the claw assembly. The inner wall of the lower end of the guide cylinder has an inwardly inclined guide surface, which corresponds to the elastic claw of the claw assembly.

2. The downhole fishing tool as described in claim 1, characterized in that, It also includes a limit unlocking component, which includes a sliding sleeve fitted outside the guide cylinder. The guide cylinder has two positioning grooves symmetrically arranged around the center. The upper section of the claw component has a horizontal pin, and the two ends of the horizontal pin pass through the corresponding positioning grooves and are connected to the sliding sleeve.

3. The downhole fishing tool as described in claim 2, characterized in that, The positioning groove is an L-shaped groove, consisting of an axial groove arranged along the axial direction and a circumferential groove arranged along the circumferential direction.

4. The downhole fishing tool as described in claim 2, characterized in that, The two ends of the horizontal pin are connected to the sliding sleeve by screw threads.

5. The downhole fishing tool as described in any one of claims 1-4, characterized in that, The claw assembly includes an upper claw seat and a lower claw with multiple elastic hooks.

6. The downhole fishing tool as described in claim 5, characterized in that, The top of the card holder is provided with a lower spring seat for mounting the spring assembly.

7. The downhole fishing tool as described in any one of claims 1-4, characterized in that, The spring assembly includes an upper end head mounted on the upper end of the guide cylinder and a compression spring located between the upper end head and the claw assembly.

8. The downhole fishing tool as described in claim 7, characterized in that, The bottom of the upper end is provided with an upper spring seat.

9. The downhole fishing tool as described in claim 7, characterized in that, The lower end of the upper end head is threadedly connected to the guide cylinder, and the upper end is provided with a connecting section that can be connected to the extension rod.

10. The downhole fishing tool as described in any one of claims 1-4, characterized in that, The guide cylinder has multiple drainage holes.

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