Underground fishing device

Abstract

The invention relates to an underground fishing device. The underground fishing device comprises a shell, a driving assembly arranged in a mounting cavity of the shell and a fishing assembly arranged in a cavity of the shell. And the mounting cavity is separated from the cavity. And the lower end of the shell is also provided with a guide hole. The salvage assembly comprises a sliding barrel connected with the driving assembly and at least two salvage pieces arranged oppositely below the sliding barrel, and an elastic piece in a compressed state is arranged between the two salvage pieces. And the driving assembly is configured to enable the fishing assembly to move in the axial direction, so that the two fishing pieces can be far away from each other under the action of the elastic piece when moving to the guide hole, and a fishing head of a target device can be connected or released. According to the fishing device, the fishing assembly can be driven by the driving assembly to fish the underground target device, and the target device can be placed at the underground preset position, so that the well entering efficiency is effectively improved, and the operation cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole fishing, in particular to a fishing device for downhole. BACKGROUND

[0002] In the process of oil drilling, as the drilling depth increases, the failure rate of the measurement-while-drilling instrument also increases. Once the measurement-while-drilling instrument fails, it must be fished out in time. Long-term delay will cause the instrument to be scrapped and affect the subsequent more complex drilling construction. This not only greatly prolongs the drilling time, but also increases the drilling cost.

[0003] Currently, there are mainly two ways to replace or repair the measurement-while-drilling instrument. The first way is to lift the drill pipe. That is, after stopping drilling, the drill pipe is fished up one by one until the measurement-while-drilling instrument at the drill pipe is fished out of the well, and then the measurement-while-drilling instrument can be repaired or replaced. Lifting the drill pipe to the ground for disassembly will increase labor intensity, prolong working time, and have low efficiency, thereby causing unnecessary economic losses. The second way is to use a mechanical fishing tool to fish out the wireless measurement-while-drilling device by clamping the fishing head. Although this saves a lot of time, the existing fishing device can only fish but cannot release. Moreover, the fishing head is easy to fall off from the clamping position during fishing, affecting the fishing progress. SUMMARY

[0004] Based on the above problems in the prior art, the present application provides a fishing device for downhole, which can fish and release, and can increase the success rate of fishing.

[0005] The technical scheme adopted by the present application to solve the technical problems is to provide a fishing device for downhole, comprising,

[0006] a housing, an installation cavity is constructed in the inside of the housing, and a cavity is separated from the installation cavity, a guide hole is arranged at the lower end of the housing;

[0007] a driving assembly arranged in the installation cavity; and

[0008] a fishing assembly arranged in the cavity, the fishing assembly comprises a sliding cylinder connected with the driving assembly, and at least two fishing pieces arranged oppositely below the sliding cylinder, and an elastic piece in a compressed state is arranged between the two fishing pieces,

[0009] wherein the driving assembly is configured to move the fishing assembly in the axial direction, so that the two fishing pieces can move away from each other under the action of the elastic piece when the two fishing pieces move to the guide hole, so as to engage or release the fishing head of the target device.

[0010] Further, each of the fishing members comprises a resisting portion resisting against the elastic member, and a fishing portion connected with the resisting portion, and the two fishing members are configured to move away from each other under the action of the elastic member when the connecting portions of the resisting portion and the fishing portion move to the guide hole in the axial downward direction.

[0011] Further, the fishing assembly comprises a connecting rod connected with the sliding cylinder, and a mounting rod for connecting the connecting rod and the fishing members, and the mounting rod is provided with a mounting member for mounting the fishing members, and the mounting member is configured to make the fishing portions of the two fishing members move away from each other under the action of the elastic member when the connecting portions of the resisting portion and the fishing portion move to the guide hole in the axial downward direction.

[0012] Further, the mounting member is configured to slide along the mounting rod so as to make the two fishing members move in the direction away from each other under the action of the elastic member when the connecting portions of the resisting portion and the fishing portion move to the guide hole in the axial downward direction.

[0013] Further, the mounting member is fixed on the mounting rod, and the mounting member is hinged with the fishing member, so that the two fishing members can rotate in the direction away from each other under the action of the elastic member when the connecting portions of the resisting portion and the fishing portion move to the guide hole in the axial downward direction.

[0014] Further, the two fishing members are also configured to move close to each other under the guidance of the guide hole when the connecting portions of the resisting portion and the fishing portion move in the axial upward direction, so that the fishing portions can resist the rod member of the fishing head in the radial inward direction, thereby engaging with the fishing head.

[0015] Further, the driving assembly comprises a motor arranged in the mounting cavity, and the output end of the motor is provided with a lead screw screwed with the sliding cylinder, and the sliding cylinder is limited in the circumferential direction by the shell, so that the sliding cylinder can move in the axial direction during the rotation of the lead screw driven by the motor.

[0016] Further, the sliding cylinder is provided with a filter portion and a filter member, and the filter member divides the cavity into a first cavity and a second cavity, and the filter portion and the filter member are configured to filter solid impurities in the drilling fluid, so that the solid impurities can only be located in the second cavity.

[0017] Further, the lead screw comprises a connecting section located in the mounting cavity, and a threaded section located in the first cavity, and the threaded section is screwed with the nut on the sliding cylinder.

[0018] Further, the connecting section is connected with the output end of the motor through a shaft coupling and a gear box.

[0019] The fishing device for downhole provided by the application comprises a shell, a driving assembly arranged in a mounting cavity of the shell, and a fishing assembly arranged in a cavity of the shell. The mounting cavity and the cavity are separated from each other. A guide hole is further arranged at the lower end of the shell. The fishing assembly comprises a sliding cylinder connected with the driving assembly, and at least two oppositely arranged fishing pieces arranged below the sliding cylinder, and an elastic piece arranged between the two fishing pieces in a compressed state. The driving assembly is configured to move the fishing assembly in an axial direction, so that the two fishing pieces can move away from each other under the action of the elastic piece when the two fishing pieces move to the guide hole, so as to engage or release the fishing head of a target device. The fishing device can not only drive the fishing assembly to fish the target device in the downhole through the driving assembly, but also can place the target device at a predetermined position in the downhole, thereby effectively improving the efficiency of entering the well and reducing the operation cost. In addition, the fishing device is further provided with a filter and a filter part, which can filter the solid particles in the drilling fluid in the downhole, prevent the solid particles from aggravating the wear of the lead screw in the driving assembly, and thereby prolong the service life of the fishing device. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application will be further described below in combination with the drawings and embodiments.

[0021] Figure 1 Fig. 1 shows a structural schematic diagram of a fishing device for downhole.

[0022] In the drawings, the reference signs are as follows: 100, fishing device; 10, shell; 11, connecting part; 111, mounting cavity; 12, cavity; 121, first cavity; 122, second cavity; 13, guide hole;

[0023] 20, driving assembly; 21, motor; 22, shaft coupling; 23, lead screw; 231, connecting section; 232, threaded section; 24, gear box;

[0024] 30, fishing assembly; 301, fishing piece; 302, fishing part; 303, abutting part; 31, sliding cylinder; 311, nut; 312, filter part; 32, connecting rod; 33, mounting rod; 331, mounting piece; 34, filter; 35, elastic piece;

[0025] 40, fishing head; 41, rod piece; 42, engaging part; 421, engaging surface; 43, guide part. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be described in detail with reference to the accompanying drawings. The drawings are simplified schematic diagrams, and only schematically illustrate the basic structure of the present application, and thus only show the components related to the present application. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0027] Reference Figure 1 As shown in the drawings, the fishing device for downhole provided by the present application comprises a housing 10, and a driving assembly 20 and a fishing assembly 30 arranged in the housing 10 in sequence in the direction of axial downward movement. The driving assembly 20 is configured to change the fishing area when the fishing assembly 30 moves in the direction of axial downward movement, so as to fish or lower a target device (not shown in the drawings) to be fished in downhole to a predetermined position by the fishing assembly 30. It can be understood that the target device can be a measurement-while-drilling instrument or other downhole device. The upper end of the target device is provided with a fishing head 40 capable of engaging with the fishing assembly 30, so as to enable the fishing device 100 to fish the target device.

[0028] Reference Figure 1 As shown in the drawings, in some embodiments, the housing 10 is generally in a cylindrical structure. The upper end of the housing 10 is provided with a connecting portion 11 for connecting a rod-shaped or rope-shaped object such as a drill rod, a wire or a rope, so as to lower or pull out the fishing device 100 from downhole. The connecting portion 11 is configured with a mounting cavity 111 for mounting the driving assembly 20, and the mounting cavity 111 is not in communication with a cavity 12 inside the housing 10, so as to avoid the short circuit failure of the driving assembly 20 caused by the fluid such as drilling fluid in downhole entering the cavity 12 and then entering the mounting cavity 111. In some embodiments, the connecting portion 11 is further provided with a closure (not shown in the drawings), so that the mounting cavity 111 is a closed chamber, thereby avoiding the fluid such as drilling fluid in downhole directly entering the mounting cavity 111. The closure can be a cover plate provided with a sealing ring or a sealing gasket. For this, the present application will not be described in more detail.

[0029] In some preferred embodiments, an insulating liquid is also filled in the installation cavity 111. The insulating liquid can balance the pressure inside and outside the installation cavity 111 to some extent, avoid the deformation of the connecting part 11 after being subjected to the pressure of the drilling fluid in the well, and avoid the sealing failure between the connecting part 11 and the closure to cause the drilling fluid in the well to enter the installation cavity 111. In addition, the insulating liquid can also timely conduct the heat generated by the driving assembly 20 during operation to the casing 10 and then to the drilling fluid in the well, thereby improving the heat dissipation efficiency of the driving assembly 20. The insulating liquid can be insulating hydraulic oil. For this reason, the present application will not be described in more detail.

[0030] In combination Figure 1 As shown in some embodiments, a guide hole 13 for the fishing member 301 of the fishing assembly 30 to pass through is formed on the lower end side wall of the casing 10. The fishing member 301 can extend out of the casing 10 from the guide hole 13 to increase the fishing area of the fishing assembly 30, and can be retracted into the cavity 12 inside the casing 10 under the guidance of the edge of the guide hole 13. For this reason, it will be described in detail below.

[0031] Referring again to Figure 1 As shown in some embodiments, the driving assembly 20 includes a motor 21 arranged in the installation cavity 111, a shaft coupling 22 connected to the output shaft of the motor 21, and a lead screw 23 arranged at the end of the shaft coupling 22 away from the motor 21. The motor 21 can be connected to the power supply on the ground through wires, or can be electrically connected to the control module on the ground through wires. It can be understood that the motor 21 can also be powered by a battery, and data and / or instructions can be transmitted to the control module on the ground through wireless signals. The lead screw 23 is provided with a connecting section 231 located in the installation cavity 111 and a threaded section 232 located in the cavity 12. The connecting section 231 of the lead screw 23 is rotatably and sealingly connected to the casing 10, so that the lead screw 23 can rotate relative to the casing 10 under the drive of the motor 21, and it is ensured that the drilling fluid entering the cavity 12 through the guide hole 13 cannot enter the installation cavity 111 through the lead screw 23 and the casing 10.

[0032] In some embodiments, a gear box 24 is further arranged between the shaft coupling 22 and the lead screw 23, for converting the high-speed low-torque power output by the motor 21 into low-speed high-torque power. In some embodiments, the motor 21 can transmit high-speed low-torque power to the gear box 24 through the shaft coupling 22 under the electrical drive of the power supply, and the gear box 24 drives the lead screw 23 to rotate after converting the high-speed low-torque power into low-speed high-torque power.

[0033] Referring to Figure 1As shown, in some embodiments, the retrieval assembly 30 includes a slide cylinder 31 connected to the threaded section 232 of the lead screw 23, a connecting rod 32 disposed at the lower end of the slide cylinder 31, and a mounting rod 33 for connecting the connecting rod 32 and the retrieval component 301. A nut 311, screwed to the threaded section 232, is disposed on the upper end face of the slide cylinder 31, and a filter section 312 is disposed on the side wall of the slide cylinder 31. A filter element 34 is also disposed between the slide cylinder 31 and the housing 10 to divide the cavity 12 into a first cavity 121 and a second cavity 122. The first cavity 121 and the second cavity 122 are arranged sequentially in a downward axial direction. The threaded section 232 of the lead screw 23 is completely located inside the first cavity 121 and the slide cylinder 31. The filter element 34 and the filter section 312 are configured to prevent solid particles in the drilling fluid from entering the interior of the slide 31 and the first cavity 121, thereby preventing solid particles in the drilling fluid from adhering to the threads between the threaded section 232 and the nut 311. This effectively reduces wear between the lead screw 23 and the nut 311, and improves the service life of the lead screw 23 and the nut 311.

[0034] In some embodiments, an axially oriented sliding block structure (not shown) is also provided between the filter element 34 and the housing 10, allowing the housing 10 to limit the filter element 34 in the circumferential direction, thereby preventing relative rotation between the slide cylinder 31 and the housing 10. In other embodiments (not shown), the sliding block structure may also be provided between the slide cylinder 31 and the housing 10, as long as relative rotation between the slide cylinder 31 and the housing 10 is prevented.

[0035] Combination Figure 1 As shown, in some embodiments, mounting rod 33 is provided with mounting members 331 on both sides of connecting rod 32 for connecting retrieval member 301. An elastic member 35 in a compressed state is provided between the two retrieval members 301 for adjusting the distance between the two retrieval members 301 during the axial movement of sliding cylinder 31, thereby adjusting the retrieval area of ​​retrieval assembly 30. Retrieval member 301 includes a retrieval part 302 for engaging with retrieval head 40, and a supporting part 303 for abutting against elastic member 35. One end of supporting part 303 is connected to retrieval part 302, and the other end of supporting part 303 is connected to mounting member 331.

[0036] In some embodiments, the mounting member 331 is configured to slide on the mounting rod 33. Specifically, the mounting member 331 is a slip ring fitted onto the mounting rod 33. The mounting member 331 is fixedly connected to the abutment portion 303 of the retrieval member 301.

[0037] In some embodiments, when the retrieval device 100 retrieves the target equipment downhole, the lead screw 23 rotates under the drive of the motor 21. Due to the circumferential restraint formed between the housing 10 and the slide 31, the threaded section 232 of the lead screw 23 allows the slide 31 to move axially downward via the nut 311. The slide 31 drives the retrieval component 301 to move axially downward via the connecting rod 32 and the mounting rod 33. During this process, after the connection between the supporting part 303 and the retrieval part 302 moves to the guide hole 13, the supporting parts 303 of the two retrieval components 301 move away from each other under the action of the elastic member 35, thereby increasing the retrieval area of ​​the retrieval assembly 30. Simultaneously, the two mounting members 331 slide away from each other on the mounting rod 33. This allows the retrieval parts 302 of the two retrieval components 301 to move as far apart as possible until the retrieval head 40 can extend between the two retrieval components 301.

[0038] The motor 21 then drives the lead screw 23 to rotate in the opposite direction, causing the slide cylinder 31 to move axially upward. The slide cylinder 31 drives the retrieval component 301 to move axially upward via the connecting rod 32 and the mounting rod 33. During this process, the two retrieval components 301 approach each other under the guidance of the upper edge of the guide hole 13 on the connection between the supporting part 303 and the retrieval part 302, and the two mounting components 331 slide towards each other on the mounting rod 33. This allows the retrieval parts 302 of the two retrieval components 301 to approach each other until the retrieval device 100 engages with the retrieval head 40.

[0039] In some other embodiments, the mounting member 331 is fixed to the mounting rod 33, and the mounting member 331 is hinged to the retrieval member 301.

[0040] In other embodiments, when the retrieval device 100 retrieves the target equipment downhole, the slide 31 drives the retrieval component 301 to move axially downward via the connecting rod 32 and the mounting rod 33. After the connection between the supporting part 303 and the retrieval part 302 moves to the guide hole 13, the supporting parts 303 of the two retrieval components 301 will rotate in a direction away from each other under the action of the elastic member 35. This also allows the retrieval parts 302 of the two retrieval components 301 to be as far apart as possible, thereby increasing the retrieval area of ​​the retrieval assembly 30 until the retrieval head 40 can extend between the two retrieval components 301.

[0041] As the sliding cylinder 31 moves the retrieval component 301 axially upward via the connecting rod 32 and the mounting rod 33, the two retrieval components 301 rotate towards each other under the guidance of the upper edge of the guide hole 13 at the connection between the supporting part 303 and the retrieval part 302. This still allows the retrieval parts 302 of the two retrieval components 301 to approach each other until the retrieval device 100 engages with the retrieval head 40.

[0042] refer to Figure 1 As shown, in some embodiments, the retrieval head 40 of the target device includes a rod 41 arranged in an axial direction and a joint 42 disposed at the end of the rod 41. The rod 41 is used to connect the joint 42 to the target device. The joint 42 extends radially outward at the end of the rod 41, such that a joint surface 421 facing the target device is formed on the joint 42.

[0043] In some embodiments, after the retrieval head 40 extends between the two retrieval components 301, the drive assembly 20 moves the retrieval component 30 axially upward. During this process, the two retrieval components 301 approach each other under the guidance of the upper edge of the guide hole 13 at the connection between the abutment portion 303 and the retrieval portion 302, allowing the retrieval portion 302 to abut the rod 41 radially inward. At this time, the entire retrieval device 100 is lifted, and the mating surface 421 forms an axially limited position with the retrieval portion 302 under the gravity of the target equipment. Continuing to lift the entire retrieval device 100 allows the target equipment to be retrieved from the well.

[0044] In some preferred embodiments, a guide portion 43 is also provided on the joint 42. The guide portion 43 is generally tapered to facilitate engagement between the retrieval head 40 and the retrieval assembly 30 even after the elastic element 35 fails. When the retrieval device 100 is in position below, the elastic element 35 fails due to a malfunction, causing the two retrieval components 301 to move away from each other unexpectedly. As the drive assembly 20 moves the retrieval assembly 30 axially downward, the retrieval portions 302 of the two retrieval components 301 can move away from each other under the guidance of the tapered surface of the guide portion 43 until the retrieval portions 302 move below the joint 42. As the drive assembly 20 moves the retrieval assembly 30 axially downward, the two retrieval components 301 can move closer to each other under the guidance of the upper edge of the guide hole 13 on the connection between the abutment portion 303 and the retrieval portion 302, and the retrieval assembly 30 and the retrieval head 40 can still complete the engagement.

[0045] Combination Figure 1As shown, the retrieval process of the retrieval device 100 for downhole applications provided by this invention is as follows. After the technician lowers the retrieval device 100 into position, the motor 21 drives the lead screw 23 to rotate via the control module. Due to the circumferential limit formed between the housing 10 and the slide cylinder 31, the threaded section 232 of the lead screw 23 can move the slide cylinder 31 axially downward via the nut 311, so that the slide cylinder 31 drives the retrieval component 301 to move axially downward via the connecting rod 32 and the mounting rod 33. After the connection between the supporting part 303 and the retrieval part 302 moves to the guide hole 13, the supporting parts 303 of the two retrieval components 301 will move away from each other under the action of the elastic member 35, thereby increasing the retrieval area of ​​the retrieval assembly 30. This allows the retrieval head 40 to extend between the two retrieval components 301.

[0046] Technicians then use the control module to drive the motor 21 to rotate the lead screw 23 in the opposite direction. This causes the threaded section 232 of the lead screw 23 to move the slide cylinder 31 axially upward via the nut 311. The slide cylinder 31 then drives the retrieval component 301 axially upward via the connecting rod 32 and the mounting rod 33. During this process, the two retrieval components 301 approach each other under the guidance of the upper edge of the guide hole 13 at the connection between the supporting part 303 and the retrieval part 302, allowing the retrieval part 302 to abut against the rod 41 radially inward. At this point, lifting the entire retrieval device 100 causes the mating surface 421 to form an axially limited position with the retrieval part 302 under the weight of the target equipment. Continuing to lift the entire retrieval device 100 allows the target equipment to be retrieved from the well.

[0047] The salvage device 100 provided by this invention can also release the target equipment from a predetermined position underground, and the release process is the reverse of the salvage process described above. This application will not elaborate further on this.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] It should be understood that the terms "length", "width", "up", "down", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0050] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The 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 fishing device for use in a well, comprising, a housing (10) internally configured with a mounting cavity (111) and a cavity (12) separated from the mounting cavity (111), the lower end of the housing (10) being provided with a guide hole (13); a driving assembly (20) arranged in the mounting cavity (111); and a fishing assembly (30) arranged in the cavity (12), the fishing assembly (30) comprising a sliding cylinder (31) connected with the driving assembly (20), and at least two oppositely arranged fishing pieces (301) arranged below the sliding cylinder (31), an elastic piece (35) in a compressed state being arranged between the two fishing pieces (301), wherein the driving assembly (20) being configured to enable the fishing assembly (30) to move in an axial direction, so that the two fishing pieces (301) can move away from each other under the action of the elastic piece (35) when moving to the guide hole (13) to engage or release a fishing head (40) of a target device.

2. A fishing device for use downhole as claimed in claim 1, characterised in that, Each of the fishing pieces (301) comprises an abutting portion (303) abutting against the elastic piece (35), and a fishing portion (302) connected with the abutting portion (303), the two fishing pieces (301) being configured to move away from each other under the action of the elastic piece (35) when moving to the guide hole (13) in an axial downward direction at the connection part of the abutting portion (303) and the fishing portion (302).

3. A fishing device for use downhole as claimed in claim 2, characterised in that, The fishing assembly (30) comprises a connecting rod (32) connected with the sliding cylinder (31), and a mounting rod (33) for connecting the connecting rod (32) and the fishing pieces (301), the mounting rod (33) being provided with a mounting piece (331) for mounting the fishing pieces (301), the mounting piece (331) being configured to enable the fishing portions (302) of the two fishing pieces (301) to move away from each other under the action of the elastic piece (35) when moving to the guide hole (13) in an axial downward direction at the connection part of the abutting portion (303) and the fishing portion (302).

4. The fishing device for use downhole according to claim 3, characterized in that, The mounting piece (331) is configured to slide along the mounting rod (33) to enable the two fishing pieces (301) to move away from each other in the direction under the action of the elastic piece (35) when moving to the guide hole (13) in an axial downward direction at the connection part of the abutting portion (303) and the fishing portion (302).

5. The fishing device for use downhole according to claim 3, characterized in that, The mounting piece (331) is fixed on the mounting rod (33), and the mounting piece (331) is hinged with the fishing piece (301) to enable the two fishing pieces (301) to rotate away from each other in the direction under the action of the elastic piece (35) when moving to the guide hole (13) in an axial downward direction at the connection part of the abutting portion (303) and the fishing portion (302).

6. The fishing device for use downhole of claim 1, wherein, The two fishing members (301) are also configured to move towards each other under the guidance of the guide hole (13) when the connecting part of the abutting part (303) and the fishing part (302) moves in the direction of upward axial movement, so that the fishing part (302) can abut the rod member (41) of the fishing head (40) in the direction of inward radial movement, thereby engaging with the fishing head (40).

7. A fishing device for use downhole according to any of claims 1-6, characterized in that, The driving assembly (20) comprises a motor (21) arranged in the mounting cavity (111), and an output end of the motor (21) is provided with a lead screw (23) screwed with the sliding cylinder (31), and the sliding cylinder (31) is limited in the circumferential direction with the shell (10), so that the sliding cylinder (31) can move in the axial direction during the rotation of the lead screw (23) driven by the motor (21).

8. The fishing device for use downhole according to claim 7, characterized in that, The sliding cylinder (31) is provided with a filter part (312) and a filter member (34), the filter member (34) divides the cavity (12) into a first cavity (121) and a second cavity (122), and the filter part (312) and the filter member (34) are configured to filter solid impurities in the drilling fluid, so that the solid impurities can only be located in the second cavity (122).

9. The fishing device for use downhole according to claim 8, characterized in that, The lead screw (23) comprises a connecting section (231) located in the mounting cavity (111), and a threaded section (232) located in the first cavity (121), and the threaded section (232) is screwed with a nut (311) on the sliding cylinder (31).

10. The fishing device for use downhole according to claim 9, characterized in that, The connecting section (231) is connected with the output end of the motor (21) through a shaft coupling (22) and a gear box (24).

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