Underground fishing device

Abstract

The utility model relates to an underground fishing device which comprises a shell, a driving assembly arranged in an installation 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. The driving assembly is configured to enable the fishing assembly to move in the axial direction, so that the two fishing pieces can move away from each other under the action of the elastic piece when moving to the guide hole, and therefore 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 utility model relates to the technical field of downhole fishing, and particularly relates to a fishing device for downhole. Background Art

[0002] During the process of oil drilling, as the drilling depth increases, the failure rate of the measurement-while-drilling (MWD) instrument will also increase accordingly. Once the MWD instrument fails, it must be fished out in time. Prolonged delay will cause the instrument to be scrapped due to failure to get out of the well in time, affecting subsequent more complex drilling operations. This will not only greatly prolong the drilling time but also increase the drilling cost.

[0003] At present, there are mainly two ways to replace or repair the MWD instrument. The first is to lift the drill string to the surface. That is, after stopping the drilling, the drill pipes are fished out one by one until the drill pipe where the failed MWD instrument is located is fished out of the well, and then the MWD instrument can be repaired or replaced. Lifting the drill pipe to the surface and then disassembling it will cause problems such as increased labor intensity, extended working hours, and low efficiency, resulting in unnecessary economic losses. The second is to use a mechanical fishing tool for fishing, and the wireless MWD equipment is fished out by clamping with a fishing head. Although this saves a lot of time, the existing fishing equipment can only fish but not release. Moreover, during fishing, the fishing head is prone to falling off from the clamping position, affecting the fishing progress. Summary of the Utility Model

[0004] Based on the above problems existing in the prior art, the utility model provides a fishing device for downhole, which can not only fish but also release, and can increase the success rate of fishing.

[0005] The technical solution adopted by the utility model to solve its technical problems is: to provide a fishing device for downhole, including,

[0006] A housing, which has an installation cavity and a cavity separated from the installation cavity inside, and a guiding hole is provided at the lower end of the housing;

[0007] A driving component, which is arranged in the installation cavity; and

[0008] A fishing component, which is arranged in the cavity. The fishing component includes a sliding cylinder connected to the driving component, and at least two relatively arranged fishing parts provided below the sliding cylinder. An elastic part in a compressed state is arranged between the two fishing parts.

[0009] Wherein, the driving component is configured to be able to move the fishing component in the axial direction, so that when the two fishing parts move to the guiding hole, they can move away from each other under the action of the elastic part, so as to engage or release the fishing head of the target device.

[0010] Furthermore, each of the fishing members includes a resisting portion that abuts against the elastic member, and a fishing portion connected to the resisting portion. The two fishing members are configured to move away from each other under the action of the elastic member when moving axially downward at the connecting portion of the resisting portion and the fishing portion to the guiding hole.

[0011] Furthermore, the fishing assembly includes a connecting rod connected to the sliding cylinder, and a mounting rod for connecting the connecting rod and the fishing member. The mounting rod is provided with a mounting member for mounting the fishing member. The mounting member is configured to move the fishing portions of the two fishing members away from each other under the action of the elastic member when moving axially downward at the connecting portion of the resisting portion and the fishing portion to the guiding hole.

[0012] Furthermore, the mounting member is configured to slide along the mounting rod so that the two fishing members can move away from each other under the action of the elastic member when moving axially downward at the connecting portion of the resisting portion and the fishing portion to the guiding hole.

[0013] Furthermore, the mounting member is fixed on the mounting rod, and the mounting member is hinged to the fishing member so that the two fishing members can rotate away from each other under the action of the elastic member when moving axially downward at the connecting portion of the resisting portion and the fishing portion to the guiding hole.

[0014] Furthermore, the two fishing members are also configured to move closer to each other under the guiding action of the guiding hole when moving axially upward at the connecting portion of the resisting portion and the fishing portion, so that the fishing portion can abut against the rod of the fishing head in the radially inward direction, thereby engaging with the fishing head.

[0015] Furthermore, the driving assembly includes a motor disposed in the installation cavity. The output end of the motor is provided with a lead screw screwed to the sliding cylinder. The sliding cylinder and the housing form a circumferential limit so that the sliding cylinder can move axially during the process of the motor driving the lead screw to rotate.

[0016] Furthermore, a filtering portion and a filtering member are provided on the sliding cylinder. The filtering member divides the cavity into a first cavity and a second cavity. The filtering portion and the filtering 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] Furthermore, the lead screw includes a connecting section located in the installation cavity and a threaded section located in the first cavity. The threaded section is screwed to the nut on the sliding cylinder.

[0018] Further, the connecting section is connected to the output end of the motor through a coupling and a gearbox.

[0019] The beneficial effects of the present utility model are as follows: A fishing device for downhole provided by the present utility model includes a housing, a driving assembly disposed in the installation cavity of the housing, and a fishing assembly disposed in the cavity of the housing. The installation cavity and the cavity are separated from each other. A guiding hole is further provided at the lower end of the housing. The fishing assembly includes a sliding cylinder connected to the driving assembly, and at least two relatively arranged fishing members disposed below the sliding cylinder. An elastic member in a compressed state is disposed between the two fishing members. Among them, the driving assembly is configured to be able to move the fishing assembly in the axial direction, so that when the two fishing members move to the guiding hole, they move away from each other under the action of the elastic member, so as to engage or release the fishing head of the target device. The fishing device can not only drive the fishing assembly through the driving assembly to fish the target device downhole, but also place the target device at a predetermined position downhole, thereby effectively improving the downhole efficiency and reducing the operation cost. In addition, a filtering member and a filtering portion are further provided in the fishing device, which can filter the solid particles in the downhole drilling fluid to prevent the solid particles from aggravating the wear of the lead screw in the driving assembly, thereby prolonging the service life of the fishing device. Description of the Drawings

[0020] The present utility model will be further described below with reference to the drawings and embodiments.

[0021] Figure 1 Shown is a schematic structural diagram of a fishing device for downhole.

[0022] Among them, the reference numerals in the drawings: 100, fishing device; 10, housing; 11, connecting portion; 111, installation cavity; 12, cavity; 121, first cavity; 122, second cavity; 13, guiding hole;

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

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

[0025] 40, fishing head; 41, rod member; 42, engaging portion; 421, engaging surface; 43, guiding portion. Detailed Embodiments

[0026] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present utility model in a schematic manner, so it only shows the components related to the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present utility model without creative efforts belong to the scope of protection of the present utility model.

[0027] Referring to Figure 1 As shown, a fishing device 100 for downhole provided by the present utility model includes a housing 10, and a driving assembly 20 and a fishing assembly 30 arranged in sequence along the axial downward direction inside the housing 10. The driving assembly 20 is configured to be able to change the fishing area when the fishing assembly 30 moves in the axial downward direction, so that the fishing assembly 30 can fish a target device to be fished downhole (not shown in the figure) or lower the target device to a predetermined position. It can be understood that the target device can be a measurement while drilling instrument or other downhole devices. A fishing head 40 capable of engaging with the fishing assembly 30 is provided at the upper end of the target device, so that the fishing device 100 can fish the target device.

[0028] Referring to Figure 1 As shown, in some embodiments, the housing 10 is generally a cylindrical structure. A connecting portion 11 for connecting rod-shaped or rope-shaped objects such as drill pipes, wires or ropes is provided at the upper end of the housing 10, so as to lower the fishing device 100 downhole or lift it out of the well. The connecting portion 11 is configured with an installation cavity 111 for installing the driving assembly 20, and the installation cavity 111 is not communicated with the cavity 12 inside the housing 10, so as to prevent fluids such as drilling fluid downhole from entering the installation cavity 111 through the cavity 12 and causing a short-circuit fault of the driving assembly 20. In some of these embodiments, a sealing member (not shown in the figure) is further provided on the connecting portion 11, so that the installation cavity 111 is a sealed chamber, thereby preventing fluids such as drilling fluid downhole from directly entering the installation cavity 111. The sealing member can be a cover plate installed with a sealing ring or a gasket. Regarding this, the present application will not elaborate further.

[0029] In some of the preferred embodiments, the installation cavity 111 is also filled with insulating liquid. The insulating liquid can, to a certain extent, balance the pressure inside and outside the installation cavity 111, preventing the connecting portion 11 from deforming under the pressure of the downhole drilling fluid, thereby avoiding the sealing failure between the connecting portion 11 and the sealing member and preventing the downhole drilling fluid from entering the installation cavity 111. In addition, the insulating liquid can also promptly conduct the heat generated by the driving assembly 20 during operation to the housing 10, and then to the downhole drilling fluid, thereby improving the heat dissipation efficiency of the driving assembly 20. The insulating liquid can be insulating hydraulic oil. Regarding this, the present application will not elaborate further.

[0030] Combined with Figure 1 As shown, in some embodiments, a guiding hole 13 is provided on the lower side wall of the housing 10 for the fishing member 301 of the fishing assembly 30 to pass through. The fishing member 301 can extend out of the housing 10 from the guiding hole 13 to increase the fishing area of the fishing assembly 30, and can contract into the cavity 12 inside the housing 10 under the guiding action of the edge of the guiding hole 13. Regarding this, it will be elaborated in detail below.

[0031] Referring again to Figure 1 As shown, in some embodiments, the driving assembly 20 includes a motor 21 disposed in the installation cavity 111, a coupling 22 connected to the output shaft of the motor 21, and a lead screw 23 installed at one end of the coupling 22 away from the motor 21. The motor 21 can be connected to a power source on the ground through a wire, or can be electrically connected to a control module on the ground through a wire. It can be understood that the motor 21 can also be powered by a battery and transmit data and / or instructions to the control module on the ground through a wireless signal. A connecting section 231 located in the installation cavity 111 and a threaded section 232 located in the cavity 12 are provided on the lead screw 23. The connecting section 231 of the lead screw 23 is rotationally and sealingly connected to the housing 10, enabling the lead screw 23 to rotate relative to the housing 10 under the drive of the motor 21 and ensuring that the drilling fluid entering the cavity 12 through the guiding hole 13 cannot enter the installation cavity 111 through the gap between the lead screw 23 and the housing 10.

[0032] In some of these embodiments, a gearbox 24 is further provided between the coupling 22 and the lead screw 23 for converting the high-speed and low-torque power output by the motor 21 into low-speed and high-torque power. In some of these embodiments, the motor 21 can transmit the high-speed and low-torque power to the gearbox 24 through the coupling 22 under the electrical driving action of the power source, and the gearbox 24 converts the high-speed and low-torque power into low-speed and high-torque power and then drives the lead screw 23 to rotate.

[0033] Refer to Figure 1As shown, in some embodiments, the fishing assembly 30 includes a sliding cylinder 31 connected to the threaded section 232 of the lead screw 23, a connecting rod 32 disposed at the lower end of the sliding cylinder 31, and a mounting rod 33 for connecting the connecting rod 32 and the fishing piece 301. A nut 311 screwed to the threaded section 232 is provided on the upper end face of the sliding cylinder 31, and a filtering portion 312 is provided on the side wall of the sliding cylinder 31. A filter element 34 is further provided between the sliding 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 in sequence in the axially downward direction. The threaded section 232 of the lead screw 23 is completely located inside the first cavity 121 and the sliding cylinder 31. The filter element 34 and the filtering portion 312 are configured to prevent solid particles in the drilling fluid from entering the inside of the sliding cylinder 31 and the first cavity 121, thereby preventing the solid particles in the drilling fluid from adhering to the threads between the threaded section 232 and the nut 311. This can effectively reduce the wear between the lead screw 23 and the nut 311 and improve the service life of the lead screw 23 and the nut 311.

[0034] In some of these embodiments, a chute-slider structure (not shown in the figure) is further provided between the filter element 34 and the housing 10 in the axial direction, so that the housing 10 can form a circumferential limit on the filter element 34, thereby preventing relative rotation between the sliding cylinder 31 and the housing 10. In some other embodiments not shown, the chute-slider structure may also be provided between the sliding cylinder 31 and the housing 10, as long as relative rotation between the sliding cylinder 31 and the housing 10 is prevented.

[0035] Combined Figure 1 As shown, in some embodiments, mounting members 331 are provided on both sides of the mounting rod 33 where it is located on the connecting rod 32 for connecting the fishing piece 301. An elastic member 35 in a compressed state is provided between the two fishing pieces 301 for adjusting the distance between the two fishing pieces 301 during the axial movement of the sliding cylinder 31, so as to adjust the fishing area of the fishing assembly 30. The fishing piece 301 includes a fishing portion 302 for engaging with the fishing head 40 and a abutting portion 303 for abutting against the elastic member 35. One end of the abutting portion 303 is connected to the fishing portion 302, and the other end of the abutting portion 303 is connected to the mounting member 331.

[0036] In some of these embodiments, the mounting member 331 is configured to be slidable on the mounting rod 33. Specifically, the mounting member 331 is a sliding ring sleeved on the mounting rod 33. The mounting member 331 is fixedly connected to the abutting portion 303 of the fishing piece 301.

[0037] In some of these embodiments, when the fishing device 100 fishes for the target device downhole, the lead screw 23 rotates under the driving action of the motor 21. Since circumferential limitation is formed between the housing 10 and the sliding cylinder 31, the threaded section 232 of the lead screw 23 can move the sliding cylinder 31 in the axial downward direction through the nut 311. The sliding cylinder 31 drives the fishing member 301 to move in the axial downward direction through the connecting rod 32 and the mounting rod 33. During this process, after the connecting part of the abutting part 303 and the fishing part 302 moves to the guiding hole 13, the abutting parts 303 of the two fishing members 301 will move away from each other under the action of the elastic member 35, so that the fishing area of the fishing assembly 30 is increased. At the same time, the two mounting members 331 slide in the mounting rod 33 in the direction away from each other. This can make the fishing parts 302 of the two fishing members 301 as far away from each other as possible until the fishing head 40 can extend between the two fishing members 301.

[0038] The motor 21 then drives the lead screw 23 to rotate in the reverse direction, so that the sliding cylinder 31 moves in the axial upward direction. The sliding cylinder 31 drives the fishing member 301 to move in the axial upward direction through the connecting rod 32 and the mounting rod 33. During this process, the two fishing members 301 approach each other under the guiding action of the upper edge of the guiding hole 13 on the connecting part of the abutting part 303 and the fishing part 302, and the two mounting members 331 slide in the mounting rod 33 in the direction approaching each other. This can make the fishing parts 302 of the two fishing members 301 approach each other until the fishing device 100 engages with the fishing head 40.

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

[0040] In some other embodiments, when the fishing device 100 fishes for the target device downhole, the sliding cylinder 31 drives the fishing member 301 to move in the axial downward direction through the connecting rod 32 and the mounting rod 33. After the connecting part of the abutting part 303 and the fishing part 302 moves to the guiding hole 13, the abutting parts 303 of the two fishing members 301 will rotate away from each other under the action of the elastic member 35. This can also make the fishing parts 302 of the two fishing members 301 as far away from each other as possible, so that the fishing area of the fishing assembly 30 is increased until the fishing head 40 can extend between the two fishing members 301.

[0041] During the process that the sliding cylinder 31 drives the fishing member 301 to move in the axial upward direction through the connecting rod 32 and the mounting rod 33, the two fishing members 301 rotate towards each other under the guiding action of the upper edge of the guiding hole 13 on the connecting part of the abutting part 303 and the fishing part 302. This can still make the fishing parts 302 of the two fishing members 301 approach each other until the fishing device 100 engages with the fishing head 40.

[0042] Reference Figure 1 As shown, in some embodiments, the fishing head 40 of the target device includes a rod member 41 arranged along the axial direction, and a joint portion 42 provided at the end of the rod member 41. The rod member 41 is used to connect the joint portion 42 to the target device. The joint portion 42 extends in the radially outward direction at the end of the rod member 41, so that a joint surface 421 facing the target device is formed on the joint portion 42.

[0043] In some embodiments, after the fishing head 40 extends between the two fishing members 301, the driving assembly 20 moves the fishing assembly 30 in the upward axial direction. During this process, the two fishing members 301 approach each other under the guiding action of the connecting portion of the abutting portion 303 and the fishing portion 302 at the upper edge of the guiding hole 13, so that the fishing portion 302 can abut against the rod member 41 in the radially inward direction. At this time, when the entire fishing device 100 is lifted, the joint surface 421 forms an axial limit with the fishing portion 302 under the gravity of the target device. Continuing to lift the entire fishing device 100 can lift the target device out of the well.

[0044] In some preferred embodiments, a guiding portion 43 is further provided on the joint portion 42. The guiding portion 43 is generally in a conical structure to facilitate the engagement of the fishing head 40 and the fishing assembly 30 even after the elastic member 35 fails. When the lower part of the fishing device 100 reaches the position, the elastic member 35 fails due to a fault, so that the two fishing members 301 cannot move away from each other as expected. During the process of the driving assembly 20 moving the fishing assembly 30 in the downward axial direction, the fishing portions 302 of the two fishing members 301 can move away from each other under the guiding action of the conical surface of the guiding portion 43 until the fishing portion 302 moves below the joint portion 42. During the process of the driving assembly 20 moving the fishing assembly 30 in the downward axial direction, the two fishing members 301 approach each other under the guiding action of the connecting portion of the abutting portion 303 and the fishing portion 302 at the upper edge of the guiding hole 13, and the fishing assembly 30 and the fishing head 40 can still complete the combination.

[0045] Combine Figure 1As shown in the figure, the fishing process of the fishing device 100 provided by the present utility model for underground use is as follows. After the technician positions the lower part of the fishing device 100 in place, the control module is used to drive the lead screw 23 to rotate by the motor 21. Since circumferential limitation is formed between the housing 10 and the sliding cylinder 31, the threaded section 232 of the lead screw 23 can move the sliding cylinder 31 in the axial downward direction through the nut 311, so that the sliding cylinder 31 drives the fishing member 301 to move in the axial downward direction through the connecting rod 32 and the mounting rod 33. After the connecting part of the abutting portion 303 and the fishing portion 302 moves to the guiding hole 13, the abutting portions 303 of the two fishing members 301 will move away from each other under the action of the elastic member 35, thereby increasing the fishing area of the fishing assembly 30. In this way, the fishing head 40 can extend between the two fishing members 301.

[0046] The technician then uses the control module to drive the lead screw 23 to rotate in the reverse direction through the motor 21, so that the threaded section 232 of the lead screw 23 moves the sliding cylinder 31 in the axial upward direction through the nut 311, and further makes the sliding cylinder 31 drive the fishing member 301 to move in the axial upward direction through the connecting rod 32 and the mounting rod 33. During this process, the two fishing members 301 approach each other under the guiding action of the upper edge of the guiding hole 13 on the connecting part of the abutting portion 303 and the fishing portion 302, so that the fishing portion 302 can abut against the rod member 41 in the radially inward direction. At this time, the entire fishing device 100 is lifted, and the joint surface 421 forms an axial limit with the fishing portion 302 under the gravity of the target device. Continuing to lift the entire fishing device 100 can lift the target device out of the well.

[0047] The fishing device 100 provided by the present utility model can also release the target device at a predetermined position underground, and the release process is opposite to the above fishing process. Regarding this, this application will not elaborate too much.

[0048] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection, it can be a mechanical connection, it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0049] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0050] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A fishing device for downhole, characterized in that, including, a housing (10) having an installation cavity (111) formed inside thereof and a cavity (12) separated from the installation cavity (111), and a guiding hole (13) provided at the lower end of the housing (10); a driving assembly (20) disposed in the installation cavity (111); and a fishing assembly (30) disposed in the cavity (12), the fishing assembly (30) including a sliding cylinder (31) connected to the driving assembly (20), and at least two oppositely arranged fishing members (301) provided below the sliding cylinder (31), and an elastic member (35) in a compressed state is provided between the two fishing members (301), wherein the driving assembly (20) is configured to be able to move the fishing assembly (30) in the axial direction, so that when the two fishing members (301) move to the guiding hole (13), they can move away from each other under the action of the elastic member (35) to engage or release the fishing head (40) of the target device.

2. The fishing device for downhole according to claim 1, wherein Each of the fishing members (301) includes a resisting portion (303) that abuts against the elastic member (35), and a fishing portion (302) connected to the resisting portion (303), and the two fishing members (301) are configured to be able to move away from each other under the action of the elastic member (35) when moving downward in the axial direction at the connecting portion of the resisting portion (303) and the fishing portion (302) to the guiding hole (13).

3. The fishing device for downhole according to claim 2, characterized in that, The fishing assembly (30) includes a connecting rod (32) connected to the sliding cylinder (31), and a mounting rod (33) for connecting the connecting rod (32) and the fishing member (301), and a mounting member (331) for mounting the fishing member (301) is provided on the mounting rod (33), and the mounting member (331) is configured to be able to move the fishing portions (302) of the two fishing members (301) away from each other under the action of the elastic member (35) when moving downward in the axial direction at the connecting portion of the resisting portion (303) and the fishing portion (302) to the guiding hole (13).

4. The fishing device for downhole according to claim 3, characterized in that, The mounting member (331) is configured to be able to slide along the mounting rod (33), so that the two fishing members (301) can move away from each other under the action of the elastic member (35) when moving downward in the axial direction at the connecting portion of the resisting portion (303) and the fishing portion (302) to the guiding hole (13).

5. The fishing device for downhole according to claim 3, characterized in that, The mounting member (331) is fixed on the mounting rod (33), and the mounting member (331) is hinged to the fishing member (301), so that the two fishing members (301) can rotate away from each other under the action of the elastic member (35) when moving downward in the axial direction at the connecting portion of the resisting portion (303) and the fishing portion (302) to the guiding hole (13).

6. The fishing device for downhole according to claim 2, characterized in that, The two fishing members (301) are further configured to move closer to each other under the guiding action of the guiding hole (13) when moving in the axial upward direction at the connecting part of the abutting part (303) and the fishing part (302), so that the fishing part (302) can abut against the rod (41) of the fishing head (40) in the radially inward direction, thereby engaging with the fishing head (40).

7. The fishing device for downhole according to any one of claims 1-6, characterized in that, The driving assembly (20) includes a motor (21) disposed in the installation cavity (111), and a lead screw (23) is provided at the output end of the motor (21) and is screwed to the sliding cylinder (31). The sliding cylinder (31) and the housing (10) form a circumferential limit, so that the sliding cylinder (31) can move in the axial direction during the process of the motor (21) driving the lead screw (23) to rotate.

8. The fishing device for downhole according to claim 7, characterized in that, A filtering part (312) and a filtering element (34) are provided on the sliding cylinder (31). The filtering element (34) divides the cavity (12) into a first cavity (121) and a second cavity (122). The filtering part (312) and the filtering element (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 downhole according to claim 8, wherein, The lead screw (23) includes a connecting section (231) located in the installation cavity (111) and a threaded section (232) located in the first cavity (121). The threaded section (232) is screwed to the nut (311) on the sliding cylinder (31).

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

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