Pressure-building clamping type fishing device and method
By designing a press-holding and clamping salvage device, the clamping communication hole, upper cone hole and lower cone hole are designed to solve the problem that existing tools cannot stably capture the falling fish, achieving stable salvage of falling fish and accurate judgment of the degree of fish entering, and reducing the cost of restoring oil well production.
Patent Information
- Application Number
- CN202311180530.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-13
- Publication Date
- 2025-03-14
AI Technical Summary
The existing salvage tools cannot steadily capture the falling fish, resulting in the failure of salvage and repeated salvage, which increases the workload and the cost of restoring oil and water well production. At the same time, the judgment of the degree of fish entering is inaccurate.
A pressure-holding clamping salvage device is designed, including an upper joint, sleeve, mandrel, shear pin, connecting sleeve, return spring, tile, valve seat and valve core assembly. Through the design of clamping communication holes, upper conical holes and lower conical holes, the clamping of tile and stable salvage of fish are achieved, and the sealing and return spring of valve core assembly is used to ensure the control of the liquid circulation channel and the stability of the salvage process.
The stable capture and salvage of falling fish is achieved, the number of repeated salvages is reduced, the cost of restoring oil and water well production is reduced, and the accuracy of judging the degree of fish is improved through the control of the pressure hold and liquid circulation channels.
Smart Images
Figure CN119616395A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of underground salvage, and relates to a pressure-holding clamping type salvage device and method. Background Art
[0002] With the rapid development of oilfield development technology in my country, various well repair tools have also developed rapidly. Problems often occur during the development process. During the normal development of oil and water wells, various well tools need to be put into the well for well repair operations. During the construction, drill sticking, sand buried pipe string, acid attack and fracture of tools may occur, which may easily cause the tool to fall off. At this time, it is necessary to salvage the tools in the well to restore the oil and water wells to continue production.
[0003] At present, the salvage tool used in the well is generally a slip salvage tube. This salvage tool relies on the tool's own weight and spring preload to clamp the fallen fish. However, due to the long guide shoe and insufficient slip hardness of this salvage tube, it is impossible to hold the fallen fish firmly, and ultimately the salvage fails. Repeated salvage is required, which increases the salvage workload and the cost of restoring oil and water well production. In addition, the existing salvage tools rely on the fish head to block the circulation channel and the increase in pump pressure to judge the degree of fish entry. The ground pump pressure does not change significantly, resulting in inaccurate judgment of the degree of fish entry. Summary of the invention
[0004] The present invention provides a pressure-holding clamping salvaging device and method, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problem that the existing salvaging tools cannot stably catch fallen fish.
[0005] One of the technical solutions of the present invention is achieved through the following measures: a pressure-holding clamping salvage device, including an upper joint, a sleeve, a core shaft, a shear pin, a connecting sleeve, a reset spring, a slip, a valve seat and a valve core assembly, a sleeve is fixedly installed on the outer side of the lower end of the upper joint, a core shaft is fixedly installed on the inner side of the lower end of the upper joint, a connecting sleeve is fixedly installed on the outer side of the lower end of the core shaft through the shear pin, a reset spring is provided on the outer side of the core shaft corresponding to the position between the lower end of the upper joint and the upper end of the connecting sleeve, and a plurality of clamping connecting holes that pass through the inner side and the outer side of the upper part of the core shaft corresponding to the position of the reset spring are provided along the circumference at intervals; an upper conical hole and a lower conical hole are provided at the lower end of the sleeve, the upper conical hole is a truncated cone hole that is larger at the top and smaller at the bottom, and the lower conical hole is a truncated cone hole that is smaller at the top and larger at the bottom, and a slip is fixedly installed on the outer side of the lower end of the connecting sleeve; a valve seat is fixedly installed on the inner side of the lower end of the core shaft, and a valve core assembly that can block the lower end of the core shaft when it moves upward is provided in the valve seat.
[0006] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned valve core assembly may include a valve stem and a C-shaped ring, a valve seat is provided with a valve stem with its lower end located below it, a mounting ring groove is provided on the outer side of the upper part of the valve stem, a C-shaped ring is provided in the mounting ring groove, a hanging ring groove is provided on the inner side of the valve seat corresponding to the position of the C-shaped ring, the hanging ring groove includes an upper ring groove and a lower ring groove, and the upper ring groove is in the shape of a truncated cone with a smaller upper part and a larger lower part; a connecting blind hole opening upward is provided on the upper end of the valve stem, a plurality of internal connecting holes that can be connected to the connecting blind hole are provided along the circumference at intervals on the outer side of the middle part of the valve stem corresponding to the position of the connecting blind hole, a connecting ring groove is provided on the inner side of the valve seat corresponding to the position of the internal connecting hole, and external connecting holes that can be connected to the connecting ring groove are provided on the outer side of the valve seat corresponding to the position below the internal connecting hole.
[0007] The valve core assembly may further include a collision head, and the collision head is fixedly mounted on the lower end of the valve stem.
[0008] The above may also include O-rings, at least one O-ring is provided between the core shaft and the upper joint, at least one O-ring is provided between the core shaft and the probe sleeve, at least one O-ring is provided between the core shaft and the connecting sleeve, at least one O-ring is provided between the connecting sleeve and the sleeve, at least one O-ring is provided between the valve seat and the core shaft, and at least one O-ring is provided between the valve seat and the valve stem.
[0009] The above may also include set screws. At least two set screws are provided at intervals along the circumference on the outer side of the upper end of the slip to fix it to the outer side of the lower end of the connecting sleeve.
[0010] The outer side of the lower end of the above-mentioned upper joint can be fixedly installed with a sleeve through a threaded connection, the inner side of the lower end of the upper joint can be fixedly installed with a core shaft through a threaded connection, the outer side of the lower end of the connecting sleeve can be fixedly installed with a slip through a threaded connection, and the inner side of the lower end of the core shaft can be fixedly installed with a valve seat through a threaded connection.
[0011] The second technical solution of the present invention is achieved by the following measures: A method of using the above-mentioned pressure-holding clamping salvage device comprises the following steps: (1) Entering the well: The pressure-holding clamping fishing device is lowered into the well and lowered to the fish landing position. The pump is turned on for circulation near the fish landing head. The circulation channel is kept unobstructed during the lowering process, that is, the liquid can pass through the central channel of the mandrel, the connecting blind hole, the internal connecting hole and the external connecting hole in sequence and then be discharged from the lower end of the sleeve, ensuring that the liquid can circulate normally through the central channel of the mandrel to flush the sand and wash the well; (2) Fish entering: After the fish completely enters the slip, the valve core assembly moves upward, the circulation channel is closed and locked, that is, the inner connecting hole is located above the outer connecting hole. At this time, the liquid cannot be discharged from the lower end of the sleeve through the central channel of the core shaft. The ground shows pressure holding, the lower end of the slip is located above the upper cone hole, and the slip opens; (3) Salvage: Continue to hold the pressure, cut the shear pin, release the spring, and push the connecting sleeve and the slip downward. The slip anchors the fish under the action of the upper cone hole. Under the combined action of the elastic force of the reset spring and the gravity of the fish, the slip holds the fish. The heavier the fish, the tighter the slip holds. The pressure in the pipe is held throughout the whole process until it reaches the wellhead.
[0012] The present invention has a reasonable and compact structure and an ingenious design. By setting a clamping connecting hole, when the valve core assembly blocks the lower end of the core shaft, liquid enters the area between the lower end of the upper joint and the upper end of the connecting sleeve, and acts on the upper end of the connecting sleeve, so that the connecting sleeve moves downward relative to the core shaft, shearing the shear pin, and under the action of the restoring force of the reset spring, the slip valve is assisted to move downward to anchor the fallen fish; by setting an upper tapered hole, the slip valve can hold the fallen fish; by setting a lower tapered hole, it is easy to introduce the fallen fish into the slip valve, and the invention has the characteristics of being fast, stable and efficient. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Attached Figure 1 It is a schematic diagram of the front cross-sectional structure of embodiments 1 to 7 of the present invention.
[0014] Attached Figure 2 For attachment Figure 1 Schematic diagram of the enlarged structure of the main view of the valve seat and valve core assembly.
[0015] Attached Figure 3 It is a schematic diagram of the main cross-sectional structure in the fish-entering state in Example 7.
[0016] Attached Figure 4 It is a schematic diagram of the main cross-sectional structure in the salvage state in Example 7.
[0017] The codes in the accompanying drawings are: 1 is the upper joint, 2 is the sleeve, 3 is the core shaft, 4 is the shear pin, 5 is the connecting sleeve, 6 is the return spring, 7 is the slip, 8 is the valve seat, 9 is the clamping connecting hole, 10 is the upper tapered hole, 11 is the lower tapered hole, 12 is the valve stem, 13 is the C-ring, 14 is the upper ring groove, 15 is the lower ring groove, 16 is the connecting blind hole, 17 is the inner connecting hole, 18 is the outer connecting hole, 19 is the collision head, 20 is the O-ring, 21 is the set screw, 22 is the connecting ring groove, and 23 is the fish drop. DETAILED DESCRIPTION
[0018] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.
[0019] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The layout is described in detail, such as the positional relationship of front, back, top, bottom, left, right, etc., which is based on the attached manual. Figure 1 The layout direction is determined by the
[0020] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As attached Figures 1 to 4 As shown, the pressure-holding clamping salvage device comprises an upper joint 1, a sleeve 2, a core shaft 3, a shear pin 4, a connecting sleeve 5, a reset spring 6, a slip 7, a valve seat 8 and a valve core assembly. The sleeve 2 is fixedly installed on the outer side of the lower end of the upper joint 1, the core shaft 3 is fixedly installed on the inner side of the lower end of the upper joint 1, and the connecting sleeve 5 is fixedly installed on the outer side of the lower end of the core shaft 3 through the shear pin 4. A reset spring 6 is provided on the outer side of the core shaft 3 corresponding to the position between the lower end of the upper joint 1 and the upper end of the connecting sleeve 5, and a plurality of clamping connecting holes 9 that penetrate inside and outside are provided along the circumference at intervals on the outer side of the upper part of the core shaft 3 corresponding to the position of the reset spring 6; an upper tapered hole 10 and a lower tapered hole 11 are provided on the lower end of the sleeve 2, the upper tapered hole 10 is a truncated cone hole that is larger at the top and smaller at the bottom, and the lower tapered hole 11 is a truncated cone hole that is smaller at the top and larger at the bottom, and a slip 7 is fixedly installed on the outer side of the lower end of the connecting sleeve 5; a valve seat 8 is fixedly installed on the inner side of the lower end of the core shaft 3, and a valve core assembly that can block the lower end of the core shaft 3 when it goes up is provided in the valve seat 8. During use, the present invention is put into the well and lowered to the position of the fish drop 23. The pump circulation is started near the position of the head of the fish drop 23. The circulation channel is kept unobstructed during the lowering to ensure that the liquid can circulate normally through the central channel of the core shaft 3 to flush the sand and wash the well; after the fish drop 23 completely enters the slip 7, the valve core assembly moves up, the circulation channel is closed and locked, the ground shows that the pressure is blocked, the lower end of the slip 7 is located above the upper cone hole 10, the slip 7 is opened, the pressure is continued to be blocked, the shear pin 4 is cut off, the spring is released, the reset spring 6 pushes the connecting sleeve 5 and the slip 7 downward, and the slip 7 anchors the fish drop 23 under the action of the upper cone hole 10. Under the combined action of the elastic force of the reset spring 6 and the gravity of the fish drop 23, the slip 7 locks the fish drop 23. The heavier the fish drop 23, the tighter the slip 7 will hold, and the whole process in the pipe is smooth. The pressure is held down until it reaches the wellhead. In addition, by setting the clamping connecting hole 9, when the valve core assembly blocks the lower end of the core shaft 3, the liquid enters the area between the lower end of the upper joint 1 and the upper end of the connecting sleeve 5, and acts on the upper end of the connecting sleeve 5, so that the connecting sleeve 5 moves downward relative to the core shaft 3, shearing the shear pin 4. Under the action of the restoring force of the reset spring 6, the assisting cava 7 moves downward to anchor the fallen fish 23. The entire salvage process is holding the pressure. Therefore, the additional restoring force of the reset spring 6 and the liquid pressure always act on the upper end face of the connecting sleeve 5, providing continuous assistance for the cava 7 to anchor the fallen fish 23, effectively preventing the fallen fish 23 from falling off during the salvage process. By setting the upper tapered hole 10, the cava 7 can hold the fallen fish 23. By setting the lower tapered hole 11, it is convenient to introduce the fallen fish 23 into the cava 7.
[0021] The above-mentioned pressure-holding clamping salvage device can be further optimized and / or improved according to actual needs: Embodiment 2: As attached Figures 1 to 4As shown, the valve core assembly includes a valve stem 12 and a C-shaped ring 13. The valve seat 8 is provided with the valve stem 12 with its lower end located below it, and the upper outer side of the valve stem 12 is provided with a mounting ring groove, and the C-shaped ring 13 is provided in the mounting ring groove. A hanging ring groove is provided on the inner side of the valve seat 8 corresponding to the position of the C-shaped ring 13, and the hanging ring groove includes an upper ring groove 14 and a lower ring groove 15. The upper ring groove 14 is a truncated cone with a small upper part and a large lower part; a connecting blind hole 16 with an opening upward is provided on the upper end of the valve stem 12, and a plurality of internal connecting holes 17 that can communicate with the connecting blind hole 16 are provided along the circumference at intervals on the outer side of the middle part of the valve stem 12 corresponding to the position of the connecting blind hole 16, and a connecting ring groove 22 is provided on the inner side of the valve seat 8 corresponding to the position of the internal connecting hole 17, and an external connecting hole 18 that can communicate with the connecting ring groove 22 is provided on the outer side of the valve seat 8 corresponding to the position below the internal connecting hole 17. During use, an upper annular groove 14 with a truncated cone shape that is smaller at the top and larger at the bottom is provided to facilitate the withdrawal of the C-shaped ring 13 from the upper side of the mounting annular groove; a lower annular groove 15 with a straight hole is provided to prevent the C-shaped ring 13 from withdrawing from the lower side of the mounting annular groove; a valve stem 12 with its lower end located below the valve seat 8 is provided in the valve seat 8, so that only when the fish 23 is introduced into the interior of the present invention and introduced in place, the circulation channel will be completely closed, causing a significant change in the surface pump pressure, thereby accurately judging the degree of fish entry; a connecting annular groove 22 is provided to facilitate the communication between the inner connecting hole 17 and the outer connecting hole 18; in addition, in the well state, the liquid can pass through the central channel of the core shaft 3, the connecting blind hole, and the like in sequence. 16, the inner connecting hole 17 and the outer connecting hole 18 are then discharged from the lower end of the sleeve 2, thereby keeping the circulation channel unobstructed, and sand flushing and well washing operations can be carried out to create a good wellbore environment for subsequent salvage operations; in the fish-in state, the valve stem 12 moves upward under the action of the fish drop 23, and closes the circulation channel, creating a good wellbore environment for subsequent salvage operations; in the salvage state, since the head of the fish drop 23 contacts the lower end of the valve stem 12 and provides an upward supporting force for the core shaft 3, the liquid in the core shaft 3 enters the area between the lower end of the upper joint 1 and the upper end of the connecting sleeve 5 through the clamping connecting hole 9, acts on the upper end of the connecting sleeve 5, causes the connecting sleeve 5 to move downward relative to the core shaft 3, and cuts off the shear pin 4.
[0022] Embodiment 3: As attached Figures 1 to 4 As shown, the valve core assembly also includes a collision head 19, and the collision head 19 is fixedly installed at the lower end of the valve stem 12. During use, through such a setting, the contact area between the valve stem 12 and the head of the fish drop 23 is increased. According to the requirements, the distance between the upper side of the collision head 19 and the lower side of the valve seat 8 is the first distance, and the distance between the inner connecting hole 17 and the upper end of the connecting ring groove 22 is the second distance. The first distance is greater than the second distance, thereby effectively ensuring that the fish drop 23 is introduced in place and the circulation channel is completely blocked, and the degree of fish entry is accurately judged.
[0023] Embodiment 4: As attached Figures 1 to 4As shown, it also includes an O-ring 20, at least one O-ring 20 is arranged between the core shaft 3 and the upper joint 1, at least one O-ring 20 is arranged between the core shaft 3 and the probe sleeve 2, at least one O-ring 20 is arranged between the core shaft 3 and the connecting sleeve 5, at least one O-ring 20 is arranged between the connecting sleeve 5 and the sleeve 2, at least one O-ring 20 is arranged between the valve seat 8 and the core shaft 3, and at least one O-ring 20 is arranged between the valve seat 8 and the valve stem 12. In the process of use, through such an arrangement, the sealing between the components is guaranteed.
[0024] Embodiment 5: As attached Figures 1 to 4 As shown, it also includes a set screw 21, and at least two set screws 21 are arranged at intervals along the circumference of the outer side of the upper end of the slip 7 to fix it to the outer side of the lower end of the connecting sleeve 5. During use, through such an arrangement, the connection between the slip 7 and the connecting sleeve 5 is more stable and reliable.
[0025] Embodiment 6: As attached Figures 1 to 4 As shown, a sleeve 2 is fixedly installed on the outer side of the lower end of the upper joint 1 through a threaded connection, a core shaft 3 is fixedly installed on the inner side of the lower end of the upper joint 1 through a threaded connection, a slip 7 is fixedly installed on the outer side of the lower end of the connecting sleeve 5 through a threaded connection, and a valve seat 8 is fixedly installed on the inner side of the lower end of the core shaft 3 through a threaded connection. In the process of use, this arrangement facilitates the connection and disassembly of various components.
[0026] Embodiment 7: As attached Figures 1 to 4 As shown, a method of using the above-mentioned pressure-holding clamping salvage device includes the following steps: (1) Entering the well: The pressure-holding clamping fishing device is lowered into the well and lowered to the position where the fish 23 is dropped. The pump is turned on for circulation near the position where the fish 23 is dropped. When lowering, the circulation channel is kept unobstructed, that is, the liquid can pass through the central channel of the mandrel 3, the connecting blind hole 16, the internal connecting hole 17 and the external connecting hole 18 in sequence and then be discharged from the lower end of the sleeve 2, ensuring that the liquid can circulate normally through the central channel of the mandrel 3 to flush the sand and wash the well; (2) Fish entry: After the fish 23 completely enters the slip 7, the valve core assembly moves upward, the circulation channel is closed and locked, that is, the inner communication hole 17 is located above the outer communication hole 18. At this time, the liquid cannot be discharged from the lower end of the sleeve 2 through the central channel of the core shaft 3. The ground shows pressure holding, the lower end of the slip 7 is located above the upper cone hole 10, and the slip 7 is open; (3) Salvage: Continue to hold the pressure, cut the shear pin 4, release the spring, and push the connecting sleeve 5 and the slip 7 downward. The slip 7 anchors the fish 23 under the action of the upper cone hole 10. Under the combined action of the elastic force of the reset spring 6 and the gravity of the fish 23, the slip 7 holds the fish 23. The heavier the fish 23, the tighter the slip 7 will hold. The pressure in the pipe is held throughout the whole process until it is lifted to the wellhead.
[0027] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.
Claims
1. A pressure-holding clamping salvage device, characterized in that It includes an upper joint, a sleeve, a core shaft, a shear pin, a connecting sleeve, a reset spring, a slip, a valve seat and a valve core assembly. A sleeve is fixedly installed on the outer side of the lower end of the upper joint, a core shaft is fixedly installed on the inner side of the lower end of the upper joint, a connecting sleeve is fixedly installed on the outer side of the lower end of the core shaft through a shear pin, a reset spring is provided on the outer side of the core shaft corresponding to the position between the lower end of the upper joint and the upper end of the connecting sleeve, and a plurality of clamping connecting holes that penetrate inside and outside are provided along the circumference at intervals on the outer side of the upper part of the core shaft corresponding to the position of the reset spring; an upper tapered hole and a lower tapered hole are provided on the lower end of the sleeve, the upper tapered hole is a frustum hole that is larger at the top and smaller at the bottom, and the lower tapered hole is a frustum hole that is smaller at the top and larger at the bottom, and a slip is fixedly installed on the outer side of the lower end of the connecting sleeve; a valve seat is fixedly installed on the inner side of the lower end of the core shaft, and a valve core assembly that can block the lower end of the core shaft when it moves upward is provided in the valve seat.
2. The pressure-holding clamping salvage device according to claim 1 is characterized in that The valve core assembly includes a valve stem and a C-shaped ring. A valve stem with its lower end located below the valve seat is provided in the valve seat. A mounting ring groove is provided on the outer side of the upper part of the valve stem. A C-shaped ring is provided in the mounting ring groove. A hanging ring groove is provided on the inner side of the valve seat corresponding to the position of the C-shaped ring. The hanging ring groove includes an upper ring groove and a lower ring groove. The upper ring groove is in the shape of a truncated cone with a smaller upper part and a larger lower part. A connecting blind hole opening upward is provided on the upper end of the valve stem. A plurality of internal connecting holes that can be connected to the connecting blind hole are provided along the circumference at intervals on the outer side of the middle part of the valve stem corresponding to the position of the connecting blind hole. A connecting ring groove is provided on the inner side of the valve seat corresponding to the position of the internal connecting hole. External connecting holes that can be connected to the connecting ring groove are provided on the outer side of the valve seat corresponding to the position below the internal connecting hole.
3. The pressure-holding clamping salvage device according to claim 2 is characterized in that The valve core assembly also includes a collision head, and the collision head is fixedly installed at the lower end of the valve stem.
4. The pressure-holding clamping salvage device according to claim 1, 2 or 3, characterized in that It also includes an O-ring. At least one O-ring is provided between the core shaft and the upper joint at upper and lower intervals, at least one O-ring is provided between the core shaft and the probe sleeve at upper and lower intervals, at least one O-ring is provided between the core shaft and the connecting sleeve at upper and lower intervals, at least one O-ring is provided between the connecting sleeve and the sleeve at upper and lower intervals, at least one O-ring is provided between the valve seat and the core shaft at upper and lower intervals, and at least one O-ring is provided between the valve seat and the valve stem at upper and lower intervals.
5. The pressure-holding clamping salvage device according to claim 1, 2 or 3, characterized in that It also includes fixing screws. At least two fixing screws are arranged at intervals along the circumference on the outer side of the upper end of the slip to fix it with the outer side of the lower end of the connecting sleeve.
6. The pressure-holding clamping salvage device according to claim 4, characterized in that It also includes fixing screws. At least two fixing screws are arranged at intervals along the circumference on the outer side of the upper end of the slip to fix it with the outer side of the lower end of the connecting sleeve.
7. The pressure-holding clamping salvage device according to claim 1, 2, 3 or 6, characterized in that A sleeve is fixedly installed on the outer side of the lower end of the upper joint through a threaded connection, a core shaft is fixedly installed on the inner side of the lower end of the upper joint through a threaded connection, a slip is fixedly installed on the outer side of the lower end of the connecting sleeve through a threaded connection, and a valve seat is fixedly installed on the inner side of the lower end of the core shaft through a threaded connection.
8. The pressure-holding clamping salvage device according to claim 4, characterized in that A sleeve is fixedly installed on the outer side of the lower end of the upper joint through a threaded connection, a core shaft is fixedly installed on the inner side of the lower end of the upper joint through a threaded connection, a slip is fixedly installed on the outer side of the lower end of the connecting sleeve through a threaded connection, and a valve seat is fixedly installed on the inner side of the lower end of the core shaft through a threaded connection.
9. The pressure-holding clamping salvage device according to claim 5, characterized in that A sleeve is fixedly installed on the outer side of the lower end of the upper joint through a threaded connection, a core shaft is fixedly installed on the inner side of the lower end of the upper joint through a threaded connection, a slip is fixedly installed on the outer side of the lower end of the connecting sleeve through a threaded connection, and a valve seat is fixedly installed on the inner side of the lower end of the core shaft through a threaded connection.
10. A method for a pressure-holding clamping fishing device according to any one of claims 2 to 9, characterized in that The steps include: (1) Entering the well: The pressure-holding clamping fishing device is lowered into the well and lowered to the fish landing position. The pump is turned on for circulation near the fish landing head. The circulation channel is kept unobstructed during the lowering process, that is, the liquid can pass through the central channel of the mandrel, the connecting blind hole, the internal connecting hole and the external connecting hole in sequence and then be discharged from the lower end of the sleeve, ensuring that the liquid can circulate normally through the central channel of the mandrel to flush the sand and wash the well; (2) Fish entering: After the fish completely enters the slip, the valve core assembly moves upward, the circulation channel is closed and locked, that is, the inner connecting hole is located above the outer connecting hole. At this time, the liquid cannot be discharged from the lower end of the sleeve through the central channel of the core shaft. The ground shows pressure holding, the lower end of the slip is located above the upper cone hole, and the slip opens; (3) Salvage: Continue to hold the pressure, cut the shear pin, release the spring, and push the connecting sleeve and the slip downward. The slip anchors the fish under the action of the upper cone hole. Under the combined action of the elastic force of the reset spring and the gravity of the fish, the slip holds the fish. The heavier the fish, the tighter the slip holds. The pressure in the pipe is held throughout the whole process until it reaches the wellhead.