A drilling tool fishing device and fishing method for large-diameter well construction

Abstract

The application provides a drilling tool fishing device and fishing method for large-diameter well construction, and belongs to the technical field of drilling tool fishing, and comprises a pipe nipple, a hook-shaped claw, a built-in joint and a thread-making cone. The hook-shaped claw is vertically welded at the lower end of the pipe nipple. The built-in joint is coaxially fixed at the upper end of the pipe nipple. A connecting barrel is elastically and slidably arranged in the built-in joint. A cross-shaped connecting seat is coaxially fixed at the lower end of the connecting barrel. The thread-making cone is coaxially fixed on the cross-shaped connecting seat. The outer arc surface of the pipe nipple is circumferentially and uniformly hinged with clamping claws. The top end of each clamping claw is provided with a guide groove. The end of the cross-shaped connecting seat is fixedly provided with a guide column. The application can quickly right the fish head. The thread-making cone is threadedly connected with the clamping claw to achieve double reliable fixation. The mud can drive the unlocking structure to simplify the operation process, and significantly improve the operation efficiency and construction safety.

Description

Technical Field

[0001] This application relates to the field of drill string retrieval technology, specifically to a drill string retrieval device and retrieval method for large-diameter well construction. Background Technology

[0002] Large-diameter wells are widely used in energy development, municipal construction, and emergency rescue, encompassing various types such as large-diameter gas drainage wells, ice conveying wells, and escape wells. During the construction of these wells, complex geological conditions such as uneven rock hardness and protruding rocks are frequently encountered. Drilling operations are prone to issues like tool breakage and sudden torque increases, leading to drill bit breakage at weak points. If a drill bit that has fallen into the well cannot be retrieved in time, it not only interrupts the construction process but may also render the well unusable, requiring restarting and resulting in significant losses of manpower, materials, and financial resources. Therefore, efficient and reliable drill bit retrieval equipment is crucial for ensuring the successful construction of large-diameter wells.

[0003] Currently, the core tools used in the industry to handle drill string breakage accidents include male cone retrieval tools and slip retrieval tubes. Conventional operations mostly rely on the threaded connection between the male cone and the broken-off drill string head to achieve retrieval. However, for the special scenario of large-diameter wells, the broken-off drill string head often adheres tightly to the well wall, making it difficult for conventional male cone retrieval methods to directly access the inner eye of the broken-off drill string head. Traditional auxiliary positioning methods (such as clay ball photography and camera observation methods) require repeated tripping up and down drilling to adjust the drill string curvature, which is cumbersome, time-consuming, and labor-intensive, and has poor positioning accuracy. Existing retrieval technologies cannot efficiently achieve the righting and precise positioning of drill string heads that are close to the well wall in large-diameter wells, resulting in low retrieval success rates and high construction costs.

[0004] Referring to the Chinese patent document with announcement number CN110219613A, announcement date September 10, 2019, entitled "Drill String Retrieval Device and Drill String Retrieval Method", it includes a snap cone, a guide member, and a hook-shaped member. The guide member includes a hollow body and a guide part for guiding the drill string. One end of the body is connected to the snap cone, and the other end is connected to the hook-shaped member. The guide part is located at the end of the body away from the snap cone to cooperate with the hook-shaped member to straighten the drill string.

[0005] Referring to the above technical solution, the drill string retrieval device has a hook-shaped component installed on the side of the guide body away from the snap-in cone, and a guide part is set at the end of the body away from the snap-in cone. When the top of the retrieved drill string is located in the belly part of the borehole or close to the well wall, the hook-shaped component of the drill string retrieval device is used to hook the drill string and move it away from the belly part or the well wall. Then, with the guidance of the guide part, the drill string is straightened and smoothly enters the body of the guide and the snap-in cone, which facilitates the snap-in cone to snap the drill string and remove it from the borehole. In actual use, the top of the fish head may crack or break, causing the snap-in cone to have an unstable connection when snapping with the fish head. Once it encounters foreign objects, fluctuations in lifting force, or slight tilting of the drill string during the lifting process, the already unstable connection is very easy to loosen, causing the fish head to fall off again. This will not only repeatedly increase the workload of drilling operations, further prolong the construction period and increase the cost of manpower and materials, but may also cause the fish head to get stuck in the wellbore for a second time and form a hard engagement with the well wall, resulting in the failure of the previous straightening and positioning work. Summary of the Invention

[0006] In view of this, this application provides a drilling tool retrieval device and retrieval method for large-diameter well construction, which can not only quickly straighten the fish head, but also achieve double reliable fixation by combining the threaded connection of the threaded cone and the radial clamping of the jaws. Moreover, it can simplify the operation process by using the mud-driven unlocking structure, which significantly improves the operation efficiency and construction safety.

[0007] To solve the above-mentioned technical problems, this application provides a drill string retrieval device for large-diameter well construction.

[0008] In a first aspect, this application provides a drilling tool retrieval device for large-diameter well construction, including a pipe sub, a hook-shaped claw, an internal connector, and a snap-in cone. The hook-shaped claw is vertically welded to the lower end of the pipe sub, and the internal connector is coaxially fixedly disposed at the upper end of the pipe sub. A connecting cylinder is elastically slidably assembled inside the internal connector, and a cross-shaped connecting seat is coaxially fixedly installed at the lower end of the connecting cylinder. A snap-in cone is coaxially fixedly installed on the cross-shaped connecting seat.

[0009] The outer arc surface of the tube section is uniformly hinged with grippers, and each gripper has a guide groove at its top. Each end of the cross-shaped connector is fixed with a guide post, which slides in contact with the inner wall of the corresponding guide groove. When the snap cone connects with the fish head, the tube section moves downward, causing the cross-shaped connector to move upward relative to the tube section and drive the guide post to slide in the guide groove. This drives the lower end of the gripper to rotate into the tube section to clamp the fish head.

[0010] By adopting the above technical solution, after the snap cone is fixed to the fish head, the short pipe section moves downward. The cross-shaped connecting seat moves upward relative to the short pipe section due to the obstruction of the fish head. The cross-shaped connecting seat drives the guide post to slide along the guide groove at the top of the gripper. The guide groove generates a radial guiding effect on the guide post, thereby applying a radial thrust to the top of the gripper, causing the gripper to rotate inside the short pipe section around the hinge axis. The lower end of the gripper gradually approaches and fits against the surface of the fish head, forming a circumferential clamping of the fish head, improving the stability of the fish head clamping, and preventing the fish head from shifting or falling off during the retrieval process. Moreover, no additional drive structure is required, which ensures retrieval efficiency while reducing costs and equipment complexity.

[0011] Optionally, it also includes racks and toothed blocks. The racks are circumferentially and uniformly fixed to the lower surface of the built-in connector, and the racks are in contact with the inner wall of the tube section. Each toothed block is fixedly provided with a connecting post. The connecting posts are slidably connected to the sliding holes circumferentially and uniformly opened on the side wall of the connecting cylinder. Each connecting post is fitted with a spring on its outer arc surface. The two ends of the spring abut against the outer side wall of the connecting cylinder and the toothed block, respectively. Under the action of the spring, the toothed blocks are respectively engaged with the corresponding racks for one-way locking of the cross-shaped connecting seat.

[0012] By adopting the above technical solution, when the cross-shaped connecting seat drives the connecting cylinder to move upward relative to the short section of the pipe, the toothed block moves upward synchronously with the connecting cylinder. The spring always applies a thrust away from the axis of the connecting cylinder to the toothed block, so that the toothed block continues to maintain a meshing state with the rack. The meshing structure between the rack and the toothed block restricts the connecting cylinder from moving downward relative to the built-in joint, thereby fixing the position of the cross-shaped connecting seat and ensuring that the gripper always maintains the clamping force on the fish head, preventing the gripper from loosening due to force fluctuations during the retrieval process.

[0013] Optionally, the built-in connector has a flow channel one in the middle, the buckle cone has a flow channel two in the middle, and the interior of the connecting cylinder is connected to flow channel one and flow channel two respectively.

[0014] By adopting the above technical solution, before the salvage operation, the mud enters the flow channel one of the internal joint from the external drill rod, flows into the flow channel two of the snap-fit ​​cone through the internal channel of the connecting cylinder, and is finally sprayed onto the surface and surrounding area of ​​the fish head. The flow of the mud carries away the mud skin, sand and other impurities attached to the surface of the fish head, and at the same time washes the threaded hole of the inner eye of the fish head, cleaning the surface of the fish head and the threaded hole of the inner eye, providing a clean environment for the precise docking and reliable connection of the snap-fit ​​cone and the fish head.

[0015] Optionally, a transmission cylinder is slidably fitted to the inner wall of the connecting cylinder. A second spring is provided between the lower surface of the transmission cylinder and the upper end face of the buckling cone. A sealing head is coaxially fixedly installed inside the connecting cylinder. When the second spring is in the extended state, the sealing head is inserted into the upper end of the transmission cylinder and seals the inside of the transmission cylinder. A drive bar is provided in the middle of the transmission cylinder. Inclined grooves are provided on the side walls of the connecting column. When the transmission cylinder is pressed and moves downward relative to the connecting cylinder, the drive bar drives the tooth block and the toothed rack to separate by sliding with the adjacent inclined groove, thereby releasing the locking of the gripper.

[0016] By adopting the above technical solution, after the fish head is retrieved to the ground, mud is injected into the first channel. The pressure of the mud acts on the upper end face of the transmission cylinder, overcoming the elastic force of the second spring and pushing the transmission cylinder to move downward relative to the connecting cylinder. The transmission cylinder drives the drive bar in the middle to move downward synchronously. The drive bar contacts and slides relative to the inclined groove on the side wall of the connecting column. The inclined groove is squeezed by the drive bar and generates a radial force, which drives the connecting column to move in the direction of the axis of the connecting cylinder, thereby pulling the tooth block away from the toothed bar, realizing the rapid release of the clamp lock state, and providing convenient conditions for the separation of the fish head and the buckling cone.

[0017] Optionally, the drive bar has a wedge-shaped structure, with the wedge-shaped surface of the drive bar fitting and conforming to the inner wall of the inclined groove, and the groove width of the inclined groove being greater than the thickness of the drive bar.

[0018] By adopting the above technical solution, when the transmission cylinder drives the drive bar to move downward, the wedge-shaped surface of the drive bar fully fits the inner wall of the inclined slide groove. The wedge structure converts the axial force of the transmission cylinder into a radial thrust on the connecting column. At the same time, the wide groove width of the inclined slide groove provides sufficient sliding space for the drive bar, avoiding jamming or interference between the drive bar and the inclined slide groove when the tooth block moves upward relative to the rack.

[0019] Optionally, a connecting pipe is coaxially fixedly provided at the upper end of the connecting cylinder, and the upper end of the connecting pipe is slidably connected to the inner wall of the flow channel. A connecting pipe is coaxially fixedly provided at the lower end of the transmission cylinder, and the lower end of the connecting pipe is slidably connected to the inner wall of the flow channel. A spring is sleeved on the outer arc surface of the connecting pipe.

[0020] By adopting the above technical solution, when the connecting cylinder slides up and down relative to the built-in joint, the first connecting pipe slides synchronously along the inner wall of the first flow channel, which guides the sliding direction of the connecting cylinder. At the same time, the second connecting pipe slides along the inner wall of the second flow channel, which provides guidance for the movement of the transmission cylinder. The second spring is sleeved on the outer arc surface of the second connecting pipe. The second connecting pipe restricts the radial deformation of the second spring, avoids the bending and displacement of the second spring when it is compressed, ensures the coaxiality of the connecting cylinder and the transmission cylinder during the sliding process, and avoids the adhesion and accumulation of mud that affects the normal contraction of the second spring, thus extending the service life of the second spring.

[0021] Optionally, the gripping surface of the gripper is provided with anti-slip grooves evenly distributed.

[0022] By adopting the above technical solution, when the gripper rotates into the short section of the pipe to clamp the fish head, the clamping surface of the gripper is in contact with the surface of the fish head. The anti-slip groove is embedded in the tiny bumps and depressions on the surface of the fish head, increasing the contact area between the clamping surface and the fish head. At the same time, it prevents the fish head from sliding axially or circumferentially relative to the gripper, enhances the friction between the gripper and the fish head, further improves the stability of the clamping, and prevents the fish head from slipping during the retrieval process.

[0023] Optionally, the built-in connector has an internal mounting groove, and the outer arc surface of the connecting pipe is fitted with a spring three. The top end of the spring three abuts against the top wall of the mounting groove, and the lower end of the spring three abuts against the upper surface of the connecting cylinder.

[0024] By adopting the above technical solution, when the cross-shaped connecting seat moves the connecting cylinder upward relative to the short section of the pipe, the connecting cylinder squeezes the third spring. The third spring undergoes elastic deformation and generates a reverse elastic force. After the gripper completes the gripping of the fallen fish head, the elastic force of the third spring acts on the connecting cylinder, offsetting part of the downward pulling force on the connecting cylinder during the retrieval process. At the same time, after unlocking, the elastic force of the third spring pushes the connecting cylinder downward to reset, causing the cross-shaped connecting seat and the buckling cone to move downward synchronously, helping to maintain the force balance of the connecting cylinder, facilitating the rapid reset of each component after unlocking, and preparing for the next retrieval operation.

[0025] Secondly, this application provides a method for retrieving drilling tools for large-diameter well construction, applied to the large-diameter well construction drilling tool retrieval device described in the first aspect, the retrieval method comprising:

[0026] S1. After the pipe section is connected to the external drill pipe threaded through the built-in connector, it is lowered into the well. When the hook-shaped claw moves down to below the top of the fish head, the external drill pipe is rotated so that the fish head slides into the inside of the hook-shaped claw along the channel, which drives the fish head away from the well wall and adjusts it to a vertical state, thus completing the fish head straightening operation.

[0027] S2. Use the mud prepared on site to wash the fish head. After cleaning, slowly lower the external drill rod, align the snapping cone with the inner eye of the fish head and insert it accurately. Then slowly drive the external drill rod to rotate. The built-in connector drives the connecting cylinder, cross-shaped connecting seat and snapping cone to rotate synchronously, so that the connecting thread on the outer surface of the snapping cone is tightly drilled into the threaded hole of the inner eye of the fish head, thus achieving the initial fixation of the fish head.

[0028] S3, continue moving the pipe section downwards, keeping the snap cone in fixed contact with the top of the fish head, the cross-shaped connecting seat drives the connecting cylinder to move upwards relative to the pipe section, the guide column slides in the guide groove at the top of the jaw, generating radial thrust to drive the jaw to rotate inside the pipe section around the hinge axis, completing the stable clamping of the fish head, and gradually pulling it upwards with the external drill rod to smoothly lift the fish head out, completing the lifting and retrieval operation;

[0029] S4. Inject mud into the flow channel one of the built-in connector. The mud pressure pushes the transmission cylinder to slide downward against the elastic force of spring two. The wedge-shaped drive bar in the middle of the transmission cylinder slides and engages with the inclined groove on the side wall of the connecting column, driving the tooth block to move closer to the axis of the connecting cylinder. The tooth block separates from the tooth bar, releasing the gripper from the fish head. By manually rotating the fish head, it is disengaged from the connecting thread of the buckle cone, completing the disassembly of the fish head.

[0030] By adopting the above technical solution, the fish head is first straightened by hook-shaped claws, then cleaned by mud washing, and initially fixed by a snap cone. Subsequently, the fish head is further stabilized by gripping with claws, and finally the fish head is disassembled by unlocking the claws with mud pressure. Each step is linked to form a complete retrieval operation process, ensuring that each step provides a guarantee for the subsequent process, achieving efficient and stable retrieval of fish heads in large-diameter wells, reducing the difficulty and risk of retrieval operations, and improving the success rate of operations.

[0031] Optionally, in step S3, the gripper rotates inside the short tube section about the hinge axis, and the elastic force of spring one pushes the toothed block to mesh with the rack, thereby achieving one-way locking of the cross-shaped connecting seat.

[0032] By adopting the above technical solution, when the gripper rotates into the short section of the pipe, the connecting cylinder moves upward synchronously with the cross-shaped connecting seat. The spring continuously applies a pushing force to the toothed block, keeping the toothed block engaged with the rack. The one-way locking structure prevents the connecting cylinder from moving downward, thereby fixing the rotation angle of the gripper and ensuring that the gripper's clamping force on the fish head remains stable. This avoids the gripper loosening due to the downward movement of the connecting cylinder during the retrieval and lifting process, ensuring the stability and safety of the fish head during the lifting process.

[0033] In summary, compared with the prior art, this application includes the following beneficial technical effects:

[0034] 1. After the snap cone and the fish head are fixed, the short pipe section is moved downwards. The cross-shaped connector is blocked by the fish head and moves upwards relative to the short pipe section. The cross-shaped connector drives the guide post to slide along the guide groove at the top of the gripper. The guide groove generates a radial guiding effect on the guide post, which in turn applies a radial thrust to the top of the gripper, causing the gripper to rotate inside the short pipe section around the hinge axis. The lower end of the gripper gradually approaches and fits against the surface of the fish head, forming a circumferential clamping of the fish head, improving the stability of the fish head clamping, and preventing the fish head from shifting or falling off during the retrieval process. No additional drive structure is required, which ensures retrieval efficiency while reducing costs and equipment complexity.

[0035] 2. The meshing structure of the rack and toothed block restricts the downward movement of the connecting cylinder relative to the built-in connector, thereby fixing the position of the cross-shaped connecting seat and ensuring that the gripper always maintains the gripping force on the fish head, preventing the gripper from loosening due to force fluctuations during the retrieval process.

[0036] 3. After the fish head is retrieved to the ground, mud is injected into the first channel. The pressure of the mud acts on the upper end face of the transmission cylinder, overcoming the elastic force of the second spring and pushing the transmission cylinder to move downward relative to the connecting cylinder. The transmission cylinder drives the drive bar in the middle to move downward synchronously. The drive bar contacts and slides relative to the inclined groove on the side wall of the connecting column. The inclined groove is squeezed by the drive bar and generates a radial force, which drives the connecting column to move in the direction of the connecting cylinder axis, thereby pulling the tooth block away from the toothed bar, realizing the rapid release of the clamp lock state, and providing convenient conditions for the separation of the fish head and the buckling cone. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of a drill string retrieval device for large-diameter well construction according to this application;

[0038] Figure 2 This is a structural schematic diagram of the cross-sectional plane of this application;

[0039] Figure 3 For this application Figure 2 A magnified structural diagram of region A in the middle;

[0040] Figure 4 This is a schematic diagram of the structure of the built-in connector in this application;

[0041] Figure 5 This is a schematic diagram of the transmission cylinder and drive bar of this application;

[0042] Figure 6 This is a schematic diagram of the gripper structure of this application;

[0043] Figure 7 This is a top view of the cross-shaped connector of this application.

[0044] Figure 8 This is a schematic diagram of the toothed block and connecting column of this application;

[0045] Figure 9 This is a schematic diagram of the structure of the connecting cylinder, slider, and connecting pipe of this application.

[0046] Explanation of reference numerals in the attached drawings: 1. Pipe section; 101. Groove; 102. Strip groove; 2. Hook-shaped gripper; 201. Vortex guide groove; 3. Internal connector; 4. Buckling cone; 5. Connecting cylinder; 51. Slider; 6. Cross-shaped connecting seat; 7. Clamping claw; 8. Guide groove; 9. Guide post; 10. Spring three; 11. Rack; 12. Tooth block; 13. Connecting post; 14. Spring one; 15. Flow channel one; 16. Flow channel two; 17. Transmission cylinder; 18. Spring two; 19. Sealing head; 20. Drive bar; 21. Inclined slide groove; 22. Connecting pipe one; 23. Connecting pipe two; 24. Anti-slip groove; 25. Mounting groove. Detailed Implementation

[0047] The following will be described in conjunction with embodiments of this application. Figures 1-9 The technical solutions of the embodiments of this application are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of this application are within the scope of protection of this application.

[0048] Firstly, this application provides a drill string retrieval device for large-diameter well construction, employing the following technical solution:

[0049] Reference Figure 1 and Figure 2 This embodiment provides a drilling tool retrieval device for large-diameter well construction, including a pipe section 1, a hook-shaped claw 2, an internal connector 3, and a snapping cone 4. The hook-shaped claw 2 is vertically welded to the lower end of the pipe section 1. The hook-shaped claw 2 is made of elliptical steel plate. By cutting a vortex guide groove 201 on the elliptical steel plate, a hook-shaped clamping part extending along the vortex trajectory is formed on the edge of the steel plate. The inner end of the vortex guide groove 201 is coaxially arranged with the pipe section 1 to straighten the tilted fish head in the well to a vertical state. The lower end of the pipe section 1 has a groove 101 for the fish head to enter the interior. The internal connector 3 is coaxially fixed to the upper end of the pipe section 1. The internal connector 3 is used to connect the pipe section 1 to the external drill pipe. The internal connector 3 has a connecting cylinder 5 elastically slidingly assembled inside. The top of the connecting cylinder 5 has sliders 51 evenly arranged around its circumference (see reference). Figure 9 The built-in connector 3 has evenly spaced straight grooves on its inner circumference. The slider 51 is slidably connected to the inner wall of the corresponding straight groove. The lower end of the connecting cylinder 5 is coaxially fixed with a cross-shaped connecting seat 6 (see reference). Figure 3 and Figure 7A snap cone 4 is coaxially fixed on the cross-shaped connecting seat 6. The outer surface of the snap cone 4 is provided with connecting threads for threaded connection with the threaded hole of the inner eye of the fish head.

[0050] The pipe section 1 is connected to the external drill pipe via the internal connector 3. The external drill pipe is then lowered into the well, driving the pipe section 1. When the hook-shaped claw 2 moves to a position 100mm-150mm below the top of the fish head, the external drill pipe is rotated approximately 90 degrees using pipe wrenches. Since the inner end of the vortex guide groove 201 of the hook-shaped claw 2 is coaxial with the pipe section 1, rotating the external drill pipe guides the fish head along the groove into the inside of the claw. Simultaneously, the 90-degree rotation causes the hook-shaped clamping part to engage with the shoulder of the fish head. The vortex guide groove 201 guides the fish head into the inside of the hook-shaped claw 2, and the hook-shaped clamping part engages with the shoulder of the fish head, causing the fish head to leave the well wall and be adjusted to a vertical position. The internal connector 3 has a flow channel 15 in the middle, and the buckling cone 4 has a... There is a flow channel 2 16. The interior of the connecting cylinder 5 is connected to the flow channel 1 15 and the flow channel 2 16 respectively. The mud prepared on site is used to flush the fish head in the well through the flow channel 1 15, the connecting cylinder 5 and the flow channel 2 16 in sequence. Then, the external drill pipe is slowly lowered so that the fish head in the well enters the pipe section 1. Since the hook claw 2 has already straightened the fish head to be coaxial with the pipe section 1, when the external drill pipe is slowly lowered, the snap cone 4 is naturally aligned with the inner eye of the fish head under the coaxial guidance and is accurately inserted into it. The external drilling tool is slowly started. The external drill pipe drives the internal connector 3 to rotate. The straight sliding groove sidewall of the internal connector 3 drives the connecting cylinder 5 and the cross-shaped connecting seat 6 to rotate through the slider 51, so that the snap cone 4 is tightly drilled into the inner eye of the fish head and the fish head is initially fixed.

[0051] Reference Figure 1 and Figure 2 The outer arc surface of the pipe section 1 is uniformly hinged with clamps 7, and the side wall of the pipe section 1 is uniformly provided with strip grooves 102 for avoiding the clamps 7 (see reference). Figure 1 The gripping surfaces of the claws 7 are evenly provided with anti-slip grooves 24. The anti-slip grooves 24 increase the friction between the claws and the fish head, and at the same time prevent the claws 7 from failing to adhere tightly to the surface of the fish head due to sand particles adhering to the side of the fish head. The top of each claw 7 is provided with a guide groove 8, and the top of the guide groove 8 is inclined towards the axis of the tube section 1 (refer to...). Figure 6 The ends of the cross-shaped connector 6 are all fixedly provided with guide posts 9, which slide in cooperation with the inner walls of the corresponding guide grooves 8. The built-in connector 3 has an installation groove 25 inside, and a spring 10 is installed in the installation groove 25 (see reference). Figure 2 The top end of spring 310 abuts against the top wall of mounting groove 25, and the lower end of spring 310 abuts against the upper surface of connecting cylinder 5.

[0052] After the snap cone 4 is threadedly connected to the fish head, the pipe section 1 is moved downward. At this time, since the snap cone 4 is fixedly abutted against the top of the fish head, the cross-shaped connecting seat 6 drives the connecting cylinder 5 to move upward relative to the pipe section 1. The spring 10 is compressed, and the cross-shaped connecting seat 6 drives the guide post 9 to slide in the guide groove 8, generating a radial thrust on the top of the clamp 7. This drives the clamp 7 to rotate inside the pipe section 1 around the hinge axis. The lower end of the clamp 7 passes through the strip groove 102 to clamp the fish head, improving the fixing effect of the fish head.

[0053] Reference Figure 2 and Figure 3 It also includes racks 11 and toothed blocks 12. The racks 11 are circumferentially and uniformly fixed to the lower surface of the built-in connector 3. The racks 11 are all in contact with the inner wall of the pipe section 1 to ensure that the racks 11 are axially fixed and do not shift radially. Each toothed block 12 is fixedly provided with a connecting post 13. The connecting posts 13 are slidably connected to the sliding holes that are uniformly opened circumferentially on the side wall of the connecting cylinder 5. The outer arc surface of each connecting post 13 is fitted with a spring 14. The two ends of the spring 14 abut against the outer side wall of the connecting cylinder 5 and the toothed block 12, respectively. Under the elastic force of the spring 14, the toothed block 12 moves in a direction away from the axis of the connecting cylinder 5 and respectively engages with the corresponding rack. During the upward movement of the cross-shaped connecting seat 6 relative to the tube section 1, the teeth of both the rack 11 and the toothed block 12 are unidirectional helical teeth. When the cross-shaped connecting seat 6 moves upward, the helical tooth surface of the rack 11 presses against the helical tooth surface of the toothed block 12, forcing the toothed block 12 to contract in the axial direction, and the spring 14 is compressed. When the toothed block 12 moves to the adjacent tooth groove position of the rack 11, the elastic force of the spring 14 pushes the toothed block 12 to reset, so that the teeth and tooth grooves mesh, which is used for the unidirectional locking of the cross-shaped connecting seat 6, preventing the connecting cylinder 5 and the built-in connector 3 from moving downward relative to the tube section 1, so that the gripper 7 keeps the fish head clamped.

[0054] Reference Figure 2 and Figure 3 The inner wall of the connecting cylinder 5 is slidably fitted with a transmission cylinder 17. A second spring 18 is provided between the lower surface of the transmission cylinder 17 and the upper end face of the buckling cone 4. A sealing head 19 is coaxially fixedly installed inside the connecting cylinder 5. When the second spring 18 is in the extended state, the sealing head 19 is inserted into the upper end of the transmission cylinder 17 and seals the inside of the transmission cylinder 17. A drive bar 20 is provided in the middle of the transmission cylinder 17. The side walls of the connecting column 13 are all provided with inclined sliding grooves 21 (see reference). Figure 8 When the transmission cylinder 17 is pressed and moves downward relative to the connecting cylinder 5, the drive bar 20, through sliding engagement with the adjacent inclined groove 21, drives the toothed block 12 to overcome the elastic force of the spring-14 and move towards the center of the connecting cylinder 5, thereby separating the toothed block 12 and the rack 11 to release the locking of the gripper 7. The drive bar 20 has a wedge-shaped structure (see reference). Figure 5The wedge-shaped surface of the drive bar 20 is adapted to fit the inner wall of the inclined slide groove 21. The width of the groove of the inclined slide groove 21 is greater than the thickness of the drive bar 20, so as to ensure that when the connecting cylinder 5 drives the toothed block 12 to move upward relative to the rack 11, the radial displacement generated by the toothed block 12 will not cause the inclined slide groove 21 and the drive bar 20 to jam, and there is always a margin of movement between them.

[0055] When the slurry cone 4 is not connected to the top of the fish head, the prepared mud is injected into the interior of the flow channel 15. At this time, the mud squeezes the transmission cylinder 17 downward, causing the transmission cylinder 17 to overcome the elastic force of the spring 18 and slide downward. The top of the transmission cylinder 17 separates from the sealing head 19. The mud enters the flow channel 16 from the interior of the transmission cylinder 17 and washes the fish head. The sealing head 19 is initially inserted into the upper end of the transmission cylinder 17 to achieve a seal. However, when the mud is injected, the mud pressure can push the transmission cylinder 17 downward to release the seal. Therefore, it will not affect the washing operation of the fish head before retrieval. After the fish head is retrieved, the lower end of the gripper 7 keeps the side of the fish head clamped, and cannot rotate the fish head to separate it from the slurry cone 4. At this time, the mud is injected again into the flow channel 15. The prepared mud is injected into the interior of channel 15. The mud squeezes the transmission cylinder 17 downward, causing the transmission cylinder 17 to overcome the elastic force of spring 2 18 and slide downward. The transmission cylinder 17 drives the drive bar 20 to move downward, so that the drive bar 20 drives the tooth block 12 to move closer to the axis of the connecting cylinder 5 through sliding engagement with the inclined slide groove 21. The tooth block 12 separates from the toothed bar 11. At this time, the lower end of the gripper 7 no longer applies pressure to the side of the fish head. The elastic force of spring 3 10 pushes the connecting cylinder 5 to reset downward. At the same time, the fish head, under its own weight, drives the buckle cone 4 and the cross-shaped connecting seat 6 to move downward relative to the short section 1 of the pipe. The lower end of the drive gripper 7 rotates in the opposite direction and separates from the fish head. Then, the fish head is rotated manually to separate the fish head from the buckle cone 4 and remove it.

[0056] Reference Figure 2 A connecting pipe 22 is coaxially fixed to the upper end of the connecting cylinder 5. The upper end of the connecting pipe 22 is slidably connected to the inner wall of the flow channel 15. A spring 10 is sleeved on the outer arc surface of the connecting pipe 22. A connecting pipe 23 is coaxially fixed to the lower end of the transmission cylinder 17. The lower end of the connecting pipe 23 is slidably connected to the inner wall of the flow channel 16. A spring 18 is sleeved on the outer arc surface of the connecting pipe 23 (see reference). Figure 3 Connecting pipe 22 limits the movement of spring 10 to prevent it from bending excessively under pressure. Connecting pipe 23 limits the movement of spring 18 to prevent it from bending excessively under pressure. At the same time, both connecting pipe 22 and connecting pipe 23 guide the flow of mud to prevent it from accumulating inside the built-in joint 3 and cross-shaped connecting seat 6 and drying out, which would affect the normal use of spring 10 and spring 18.

[0057] The implementation principle of a drill string retrieval device for large-diameter well construction according to an embodiment of this application is as follows:

[0058] After the pipe section 1 is connected to the external drill pipe threadedly through the built-in connector 3, it is lowered into the well. When the hook-shaped claw 2 moves down to a position 100mm-150mm below the top of the fish head, the external drill pipe is rotated about 90 degrees with pipe wrenches. With the help of the hook-shaped clamping part extending along the vortex trajectory on the hook-shaped claw 2, and the guiding effect of the vortex guide groove 201, the fish head slides into the inside of the hook-shaped claw 2 along the groove. At the same time, the hook-shaped clamping part is engaged with the shoulder of the fish head, which drives the fish head away from the well wall and adjusts it to a vertical state, thus completing the straightening operation of the fish head.

[0059] After straightening, the mud prepared on-site is used to carry out cleaning operations. The mud is injected into the well through the flow channel 15 of the built-in connector 3, the connecting cylinder 5, and the flow channel 2 16 of the buckling cone 4 in sequence to specifically flush the fish head until there are no loose pieces or mud residues on the surface and inside the fish head, clearing obstacles for subsequent connection operations.

[0060] After cleaning, the external drill rod is slowly lowered so that the vertical fish head can smoothly enter the pipe section 1. Since the hook-shaped claw 2 has achieved coaxial guidance, the snap cone 4 is naturally aligned with the inner eye of the fish head and accurately inserted. Then, the external drill rod is slowly driven to rotate. The internal connector 3 drives the connecting cylinder 5 and the cross-shaped connecting seat 6 to rotate synchronously through the cooperation of the straight sliding groove and the slider 51. This allows the connecting thread on the outer surface of the snap cone 4 to be tightly drilled into the threaded hole of the inner eye of the fish head, thus achieving the initial fixation of the fish head.

[0061] After initial fixation, the tube section 1 continues to move downwards. Because the snap cone 4 remains in fixed contact with the top of the fish head, the cross-shaped connecting seat 6 drives the connecting cylinder 5 to move upwards relative to the tube section 1. The spring 10 is compressed, and the guide post 9 at the end of the cross-shaped connecting seat 6 slides in the guide groove 8 at the top of the gripper 7, generating radial thrust to drive the gripper 7 to rotate around the hinge axis inside the tube section 1. The anti-slip groove 24 on the gripping surface of the gripper 7 increases the friction with the fish head. At the same time, under the elastic force of the spring 14, the tooth block 12 meshes with the rack 11 on the lower surface of the built-in connector 3, realizing the one-way locking of the cross-shaped connecting seat 6, preventing the gripper 7 from loosening, and completing the stable clamping of the fish head.

[0062] After securing the fish firmly, gently lift the drill bit and gradually pull it upwards using the external drill rod to smoothly lift the fish head out, completing the lifting and retrieval operation.

[0063] After being retrieved to the ground, when it is necessary to disassemble the fish head, mud is injected into the flow channel 15 of the internal connector 3. The mud pressure pushes the transmission cylinder 17 to slide downward against the elastic force of the spring 18. The wedge-shaped drive bar 20 in the middle of the transmission cylinder 17 slides and engages with the inclined groove 21 on the side wall of the connecting column 13, driving the tooth block 12 to move towards the axis of the connecting cylinder 5. The tooth block 12 separates from the rack 11, and the locking state is released. Under its own gravity, the fish head drives the buckle cone 4 and the cross-shaped connecting seat 6 to move downward relative to the pipe section 1. The clamp 7 rotates in the opposite direction and separates from the fish head. Finally, the fish head is manually rotated to disengage it from the connecting thread of the buckle cone 4, thus completing the disassembly of the fish head.

[0064] Secondly, this application provides a method for retrieving drilling tools for large-diameter well construction, applied to the drilling tool retrieval device for large-diameter well construction described in the first aspect. The retrieval method includes:

[0065] S1. After the pipe section 1 is connected to the external drill pipe threadedly through the built-in connector 3, it is lowered into the well. When the hook-shaped claw 2 moves down to below the top of the fish head, the external drill pipe is rotated so that the fish head slides into the inside of the hook-shaped claw 2 along the channel, which drives the fish head away from the well wall and adjusts it to a vertical state, thus completing the straightening operation of the fish head.

[0066] S2, use the mud prepared on site to wash the fish head. After cleaning, slowly lower the external drill rod, align the snap cone 4 with the inner eye of the fish head and insert it accurately. Then slowly drive the external drill rod to rotate. The internal connector 3 drives the connecting cylinder 5 and the cross-shaped connecting seat 6 to rotate synchronously through the cooperation of the straight slide groove and the slider 51, so that the connecting thread on the outer surface of the snap cone 4 is tightly drilled into the threaded hole of the inner eye of the fish head, and the fish head is initially fixed.

[0067] S3, continue to move the pipe section 1 downwards, the snap cone 4 remains fixedly abutting against the top of the fish head, the cross-shaped connecting seat 6 drives the connecting cylinder 5 to move upwards relative to the pipe section 1, the guide post 9 slides in the guide groove 8 at the top of the gripper 7, generating radial thrust to drive the gripper 7 to rotate inside the pipe section 1 around the hinge axis, completing the stable clamping of the fish head. During this process, the elastic force of the spring 14 pushes the tooth block 12 to mesh with the rack 11, realizing the one-way locking of the connecting cylinder 5 and the internal connector 3. By gradually pulling upwards through the external drill rod, the fish head is smoothly lifted out, completing the lifting and retrieval operation.

[0068] S4, inject mud into the flow channel 15 of the built-in connector 3. The mud pressure pushes the transmission cylinder 17 to slide downward against the elastic force of the spring 18. The wedge-shaped drive bar 20 in the middle of the transmission cylinder 17 slides and engages with the inclined groove 21 on the side wall of the connecting column 13, driving the tooth block 12 to move closer to the axis of the connecting cylinder 5. The tooth block 12 separates from the rack 11, releasing the gripper 7 from the fish head. By manually rotating the fish head, it is disengaged from the connecting thread of the buckle cone 4, completing the disassembly of the fish head.

[0069] Furthermore, in the description of this application, the terms "installation", "connection", "linking", and "setting" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

Claims

1. A drilling tool fishing device for large-diameter well construction, comprising a pipe spool, a hook-shaped grab claw, an internal joint and a make-up cone, the hook-shaped grab claw being vertically welded to the lower end of the pipe spool, the internal joint being coaxially fixedly arranged at the upper end of the pipe spool, an elastic connection sleeve being elastically and slidably arranged in the internal joint, a cross-shaped connecting seat being coaxially fixedly arranged at the lower end of the connection sleeve, and the make-up cone being coaxially fixedly arranged at the connecting seat, characterized in that: a plurality of clamping claws are circumferentially and uniformly hinged to the outer arc surface of the pipe spool, a guide groove is formed at the top end of each clamping claw, a guide column is fixedly arranged at the end of the cross-shaped connecting seat, and the guide column is in sliding fit with the inner wall of the corresponding guide groove, when the make-up cone is connected with the fish head, the pipe spool is moved downward, the cross-shaped connecting seat is moved upward relative to the pipe spool, and the guide column is slid in the guide groove, so as to drive the lower end of the clamping claw to rotate to the inside of the pipe spool, thereby clamping the fish head; a rack is circumferentially and uniformly fixed to the lower surface of the internal joint, the rack is in abutment with the inner wall of the pipe spool, a connecting column is fixedly arranged at the rack, the connecting column is in sliding connection with the sliding hole circumferentially and uniformly formed in the side wall of the connection sleeve, the outer arc surface of the connecting column is sleeved with a spring, and the two ends of the spring are in abutment with the outer side wall of the connection sleeve and the rack, respectively, so that the rack is in meshing connection with the corresponding rack under the action of the spring, thereby achieving one-way locking of the cross-shaped connecting seat. a flow channel one is formed in the middle of the internal joint, a flow channel two is formed in the middle of the make-up cone, and the inside of the connection sleeve is in communication with the flow channel one and the flow channel two, respectively. a transmission sleeve is in sliding fit with the inner wall of the connection sleeve, a spring two is arranged between the lower surface of the transmission sleeve and the upper end surface of the make-up cone, a sealing head is coaxially and fixedly arranged in the inside of the connection sleeve, when the spring two is in an extended state, the sealing head is inserted into the inside of the upper end of the transmission sleeve and blocks the inside of the transmission sleeve, a driving strip is arranged in the middle of the transmission sleeve, and the side wall of the connecting column is formed with an inclined sliding groove, when the transmission sleeve is pressed and moves downward relative to the connection sleeve, the driving strip is driven to separate the rack and the rack through the sliding fit with the adjacent inclined sliding groove, thereby releasing the locking of the clamping claw.

2. A large-diameter well construction drill pipe fishing device according to claim 1, characterized in that: the driving strip is in a wedge-shaped structure, the wedge surface of the driving strip is in abutment with the inner wall of the inclined sliding groove, and the width of the slot of the inclined sliding groove is greater than the thickness of the driving strip.

3. A large diameter well construction drill pipe fishing device according to claim 2, characterized in that: a communication pipe one is coaxially and fixedly arranged at the upper end of the connection sleeve, the upper end of the communication pipe one is in sliding connection with the inner wall of the flow channel one, a communication pipe two is coaxially and fixedly arranged at the lower end of the transmission sleeve, the lower end of the communication pipe two is in sliding connection with the inner wall of the flow channel two, and the spring two is sleeved with the outer arc surface of the communication pipe two.

4. A large diameter well construction drill pipe fishing device according to claim 3, characterized in that: the clamping surface of the clamping claw is uniformly formed with an anti-skid clamping groove.

5. A large diameter well construction drill pipe fishing device according to claim 3, characterized in that: an installation groove is formed in the inside of the internal joint, a spring three is sleeved with the outer arc surface of the communication pipe one, the top end of the spring three is in abutment with the top wall of the installation groove, and the lower end of the spring three is in abutment with the upper surface of the connection sleeve.

6. A large diameter well construction drill pipe fishing device according to claim 1, characterized in that: ​ 7. A large diameter well construction drill pipe fishing device according to claim 5, characterized in that: ​ 8. A method for fishing a drilling tool for large-diameter well construction, applied to the drilling tool fishing device for large-diameter well construction according to claim 7, characterized in that, ​ S1, the pipe section is connected with the external drill pipe through the built-in joint, and then is lowered into the well, when the hook-shaped grab claw is lowered to the bottom of the fish head, the external drill pipe is rotated, the fish head is slid into the inside of the hook-shaped grab claw along the groove, the fish head is driven to leave the well wall and is adjusted to the vertical state, and the centralizing operation of the fish head is completed; S2, the mud prepared on site is used to flush the fish head, after the cleaning is completed, the external drill pipe is slowly lowered, the make-up cone is accurately inserted into the inside eye of the fish head, then the external drill pipe is slowly driven to rotate, the built-in joint drives the connecting barrel, the cross-shaped connecting seat and the make-up cone to rotate synchronously, the connecting thread on the outer surface of the make-up cone is tightly screwed into the thread hole in the inside eye of the fish head, and the preliminary fixing of the fish head is realized; S3, the pipe section is continuously moved downwards, the make-up cone is kept in fixed abutment with the top of the fish head, the connecting barrel is driven to move upwards relative to the pipe section by the cross-shaped connecting seat, the guide column slides in the guide groove at the top end of the grab claw, the radial thrust drives the grab claw to rotate towards the inside of the pipe section around the hinge shaft, the stable clamping of the fish head is completed, the fish head is steadily lifted by the external drill pipe, the fishing operation is completed; S4, the mud is injected into the flow channel one of the built-in joint, the mud pressure drives the transmission barrel to slide downwards to overcome the elastic force of the spring two, the wedge-shaped driving strip in the middle of the transmission barrel is in sliding cooperation with the inclined sliding groove on the side wall of the connecting column, the gear block is driven to move towards the axis of the connecting barrel, the gear block is separated from the gear rack, the clamping of the grab claw on the fish head is released, the fish head is manually rotated to be separated from the connecting thread of the make-up cone, and the disassembly of the fish head is completed.

9. The method of claim 8, wherein: In step S3, when the grab claw rotates around the hinge shaft towards the inside of the pipe section, the elastic force of the spring one drives the gear block to engage with the gear rack, and the one-way locking of the cross-shaped connecting seat is realized.

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