Mechanical internal cutting knife for oil pipe for oil well repair

Abstract

The utility model discloses a mechanical inner cutting knife for a petroleum well repairing oil pipe, and belongs to the technical field of petroleum casing pipe repairing tools. The inner cutting knife comprises a center shaft, a lower guide cone, a friction righting anchoring mechanism, a retracting and stretching transmission mechanism and a cutting mechanism are sequentially arranged on the center shaft, one end of the retracting and stretching transmission mechanism abuts against the friction righting anchoring mechanism, and the other end of the retracting and stretching transmission mechanism abuts against the cutting mechanism. After the inner cutting knife is anchored in the casing pipe through the friction centralizing and anchoring mechanism, the casing pipe is cut through the cutting mechanism, so that the cutting mechanism is good in stability and high in cutting efficiency during cutting, and the service life of the cutting mechanism can be prolonged.

Description

Technical Field

[0001] This utility model relates to a mechanical internal cutting tool for oil well workover, belonging to the technical field of oil casing repair tools. Background Technology

[0002] Internal cutting is a common technique used in oilfield workover operations. When the casing is stuck in the well or the casing to be repaired is difficult to handle by other methods, cutting is often necessary.

[0003] For example, Chinese patent document CN206205843U discloses a hydraulic internal cutting tool, which includes an upper connector, a body, a tool holder, and a tool body. A flow divider valve, a piston, and a compression spring are installed in the central holes of the upper connector and the body. The flow divider valve is installed between the lower end of the upper connector and the body. The outer wall of the upper end of the piston is axially engaged with the body, and the inner wall of the upper end is axially engaged with the flow divider valve. The lower half of the piston is axially slidingly engaged with the central hole of the body. An axial fluid flow hole is provided on the flow divider valve above the piston, and a radial fluid flow hole is provided in the middle of the flow divider valve. The compression spring is fitted outside the piston, with its upper end engaging with the piston and its lower end engaging with the body. It uses hydraulic power to open the blade, making it easy to determine whether the cutting is complete. It is safe and reliable to operate, and has the advantages of smooth, rapid, and easy-to-control cutting.

[0004] However, this hydraulic internal cutter has poor stability when cutting oil pipes, which leads to reduced cutting efficiency and shortened cutting blade life. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides a mechanical internal cutting tool for oil well workover tubing.

[0006] This utility model is achieved through the following technical solution:

[0007] A mechanical internal cutting tool for oil well workover includes a central shaft, on which a lower guide cone, a friction straightening and anchoring mechanism, a tensioning and retracting transmission mechanism, and a cutting mechanism are sequentially arranged. One end of the tensioning and retracting transmission mechanism abuts against the friction straightening and anchoring mechanism, and the other end abuts against the cutting mechanism.

[0008] The lower guide cone is located at one end of the central shaft.

[0009] The friction straightening and anchoring mechanism includes a sliding tooth sleeve, an anchoring component, and multiple friction straightening components. The sliding tooth sleeve is mounted on the central shaft near the lower guide cone. The anchoring component is mounted on the central shaft and connected to the sliding tooth sleeve. Multiple friction straightening components are arranged in a circumferential array on the anchoring component.

[0010] The anchoring assembly includes a straightening cylinder and a sliding toothed plate. The straightening cylinder is movably mounted on the central shaft. Multiple slips are evenly distributed and movably mounted on the end of the straightening cylinder away from the lower guide cone, and the bottom of the slips is provided with a sliding groove A. A groove A is opened along the axial direction on the inner wall of the straightening cylinder. The sliding toothed plate is slidably mounted in the groove A. A leaf spring B is provided on the side of the sliding toothed plate near the straightening cylinder. The leaf spring B abuts against the bottom surface of the groove A, and the sliding toothed plate engages with the sliding toothed plate under the elastic force of the leaf spring B. A toothed positioning ring is connected to the end of the straightening cylinder near the lower guide cone by a screw D, and the toothed positioning ring is in contact with the sliding toothed plate.

[0011] The outer wall of the straightening cylinder is provided with multiple grooves B in a circular array, and multiple friction straightening components are provided one-to-one at the multiple grooves B;

[0012] The friction straightening assembly includes a friction block, which is slidably connected to the groove B. The friction block is connected to the bottom surface of the groove B through multiple compression springs. Multiple limiting screws are threaded onto the straightening cylinder near the groove B. The limiting screws are used to limit the friction block in the radial direction of the central axis.

[0013] The tensioning and retraction transmission mechanism includes a thrust ring, a hinge ring, a main spring, a main spring seat, a slip cone, and multiple pusher blocks. Multiple sliding grooves B are arranged in a circular array on the central shaft, and the sliding grooves B are arranged along the axial direction of the central shaft. The multiple pusher blocks are slidably connected to the multiple sliding grooves B in a one-to-one correspondence. The thrust ring and the hinge ring are both fitted onto all the pusher blocks. One end of the slip cone is fitted onto the hinge ring, and the other end is fitted onto the central shaft. The main spring and the main spring seat are both fitted onto the central shaft. One end of the main spring pushes the main spring seat against the stepped surface inside the slip cone, and the other end of the main spring abuts against one end of all the pusher blocks.

[0014] The cone surface of the slip cone is provided with multiple slide rails arranged in a circumferential array, and the multiple slide rails are slidably connected to the slide grooves A at the bottom of the multiple slips in a one-to-one correspondence.

[0015] The cutting mechanism includes multiple cutting components, each of which is correspondingly located in a plurality of grooves B on the central shaft.

[0016] The cutting assembly includes a support block, a leaf spring A, and a blade. The support block is rotatably connected to the two side walls of the slide groove B via screw A. The blade is rotatably connected to the two side walls of the slide groove B via screw B, and the arc-shaped head of one end of the blade extends into the arc-shaped groove at one end of the support block. One end of the leaf spring A is connected to the support block via screw C, and the other end is pressed onto the blade.

[0017] The end of the blade away from the support block abuts against the pusher block in the slide groove B.

[0018] The beneficial effects of this utility model are as follows: since the inner cutter is anchored in the sleeve by the friction straightening and anchoring mechanism, and then the sleeve is cut by the cutting mechanism, the cutting mechanism has good stability and high cutting efficiency, and helps to extend the service life of the cutting mechanism. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 for Figure 1 Sectional view along AA;

[0021] Figure 3 for Figure 1 A cross-sectional view along BB.

[0022] In the diagram: 1-Central shaft, 2-Support block, 3-Leaf spring A, 4-Blade, 5-Thrust ring, 6-Opening and closing threaded ring, 7-Pusher block, 8-Main spring, 9-Main spring seat, 10-Clip cone, 11-Limit screw, 12-Compression spring, 13-Friction block, 14-Toothed positioning ring, 15-Sliding sleeve, 16-Lower guide cone, 17-Sliding blade, 18-Straightening cylinder, 19-Leaf spring B, 20-Screw A, 21-Clip, 22-Screw B, 23-Screw C, 24-Screw D. Detailed Implementation

[0023] The technical solution of this utility model is further described below, but the scope of protection is not limited to what is described.

[0024] like Figures 1 to 3 As shown, the mechanical internal cutting tool for oil well workover of this utility model includes a central shaft 1. A lowering cone 16, a friction-aligning anchoring mechanism, a tensioning transmission mechanism, and a cutting mechanism are sequentially mounted on the central shaft 1. One end of the tensioning transmission mechanism abuts against the friction-aligning anchoring mechanism, and the other end abuts against the cutting mechanism. When the internal cutting tool needs to be lowered, the central shaft 1 is rotated clockwise. The friction-aligning anchoring mechanism moves upward relative to the central shaft 1, and its end near the tensioning transmission mechanism gradually opens outward until the internal cutting tool is anchored inside the casing (oil tubing). Simultaneously, the friction-aligning anchoring mechanism pushes the tensioning transmission mechanism upward relative to the central shaft 1, causing the cutting mechanism to open outward. Then, the central shaft 1 drives the cutting mechanism to rotate, thus cutting the casing. Because the friction-aligning anchoring mechanism anchors the internal cutting tool inside the casing before the cutting mechanism cuts the casing, the cutting mechanism has good stability and high cutting efficiency, and helps extend the service life of the cutting mechanism.

[0025] The lower guide cone 16 is located at one end of the central shaft 1. In use, the lower guide cone 16 is used to guide the inner cutter into the sleeve and to axially limit the lower end of the friction straightening and anchoring mechanism.

[0026] The friction straightening and anchoring mechanism includes a sliding tooth sleeve 15, an anchoring component, and multiple friction straightening components. The sliding tooth sleeve 15 is fitted on the central shaft 1 near the lower guide cone 16. The anchoring component is fitted on the central shaft 1 and connected to the sliding tooth sleeve 15. The multiple friction straightening components are arranged in a circumferential array on the anchoring component.

[0027] The anchoring assembly includes a straightening cylinder 18 and a sliding tooth 17. The straightening cylinder 18 is movably mounted on the central shaft 1. Multiple slips 21 are evenly distributed and movably mounted on the end of the straightening cylinder 18 away from the lower guide cone 16, and the bottom of each slip 21 has a sliding groove A. A groove A is axially formed on the inner wall of the straightening cylinder 18, and the sliding tooth 17 is slidably disposed within the groove A. A leaf spring B19 is provided on the side of the sliding tooth 17 near the straightening cylinder 18, and the leaf spring B19 abuts against the bottom surface of the groove A. Under the elastic force of the leaf spring B19, the sliding tooth 17 engages with the sliding tooth sleeve 15. A toothed positioning ring 14 is connected to the end of the straightening cylinder 18 near the lower guide cone 16 via a screw D24, and the toothed positioning ring 14 contacts the sliding tooth 17. In use, the toothed positioning ring 14 limits the lower end of the sliding tooth 17, preventing the sliding tooth 17 from sliding out of the groove A.

[0028] The outer wall of the straightening cylinder 18 is provided with a plurality of grooves B arranged in a circular array, and a plurality of friction straightening components are respectively provided at the plurality of grooves B.

[0029] The friction straightening assembly includes a friction block 13, which is slidably connected to the groove B. The friction block 13 is connected to the bottom surface of the groove B via multiple compression springs 12. Multiple limiting screws 11 are threaded onto the straightening cylinder 18 near the groove B. These limiting screws 11 are used to limit the friction block 13 radially along the central axis 1. During use, the friction block 13 partially protrudes outside the groove B under the spring force of the compression springs 12.

[0030] The tensioning and retraction transmission mechanism includes a thrust ring 5, a hinge ring 6, a main spring 8, a main spring seat 9, a slip cone 10, and multiple pusher blocks 7. Multiple sliding grooves B are arranged in a circular array on the central shaft 1, and the sliding grooves B are arranged along the axial direction of the central shaft 1. The multiple pusher blocks 7 are slidably connected to the multiple sliding grooves B in a one-to-one correspondence. The thrust ring 5 and the hinge ring 6 are both fitted on all the pusher blocks 7. One end of the slip cone 10 is fitted on the hinge ring 6, and the other end is fitted on the central shaft 1. The main spring 8 and the main spring seat 9 are both fitted on the central shaft 1. One end of the main spring 8 pushes the main spring seat 9 against the stepped surface inside the slip cone 10, and the other end of the main spring 8 abuts against one end of all the pusher blocks 7.

[0031] The conical surface of the slip cone 10 is provided with multiple slide rails arranged in a circumferential array, and the multiple slide rails are slidably connected to the slide grooves A at the bottom of the multiple slips 21.

[0032] The cutting mechanism includes multiple cutting components, each of which is correspondingly located in a plurality of grooves B on the central shaft 1.

[0033] The cutting assembly includes a support block 2, a leaf spring A3, and a blade 4. The support block 2 is rotatably connected to the two side walls of the slide groove B by screw A20. The blade 4 is rotatably connected to the two side walls of the slide groove B by screw B22, and the arc head of one end of the blade 4 extends into the arc groove at one end of the support block 2. One end of the leaf spring A3 is connected to the support block 2 by screw C23, and the other end is pressed on the blade 4.

[0034] The end of the blade 4 away from the support block 2 abuts against the pusher block 7 in the slide groove B.

[0035] The working principle or usage process of the mechanical internal cutting tool for oil well workover of this utility model is as follows:

[0036] First, lower the lower end of the inner cutter into the sleeve, then rotate the central shaft 1 clockwise. Because the friction block 13 protrudes out of the groove B under the spring force of the compression spring 12, there is a large friction force between it and the inner wall of the sleeve. Therefore, the friction straightening assembly and the anchoring assembly do not rotate with the central shaft 1. At the same time, because the sliding tooth 17 meshes with the sliding tooth sleeve 15, the friction straightening assembly and the anchoring assembly move upward relative to the central shaft 1. At this time, all the slips 21 gradually open outward under the guidance of the conical surface at the lower end of the slip cone 10 and the slide rail. When the slip 21 abuts against the inner wall of the sleeve, the sliding tooth 17 disengages from the sliding tooth sleeve 15, and the two are no longer engaged. Then, the inner cutter is lowered, and the central shaft 1 moves downward relative to the friction-aligning assembly and the anchoring assembly. That is, all the slips 21, slip cones 10, main spring seats 9, opening and closing screw rings 6, thrust rings 5, and pusher blocks 7 move upward together relative to the central shaft 1. The main spring 8 is compressed, and the pusher blocks 7 push the blade 4 to overcome the force of the leaf spring A3 and open outward around the screw B22. When the blade 4 contacts the inner wall of the sleeve, rotating the central shaft 1 drives the blade 4 to rotate, thus cutting the sleeve. After cutting is completed, the inner cutter is lifted up, and the friction straightening assembly and the anchoring assembly move downward relative to the central axis 1 until the lower end of the anchoring assembly abuts against the lower guide cone 16. At this time, all the slips 21 retract inward and lose their wedging effect. Under the action of their own weight and the spring force of the main spring 8, the slip cone 10 and the pusher block 7 move downward relative to the central axis 1, and the leaf spring A3 pushes the blade 4 inward, so that the inner cutter can be pulled out of the well.

Claims

1. A mechanical internal cutting tool for oil well workover, characterized in that: It includes a central shaft (1), on which a lower guide cone (16), a friction straightening and anchoring mechanism, a tensioning and retracting transmission mechanism and a cutting mechanism are sequentially provided. One end of the tensioning and retracting transmission mechanism abuts against the friction straightening and anchoring mechanism, and the other end abuts against the cutting mechanism. The friction straightening and anchoring mechanism includes a sliding tooth sleeve (15), an anchoring component and multiple friction straightening components. The sliding tooth sleeve (15) is fitted on the central shaft (1) near the lower guide cone (16). The anchoring component is fitted on the central shaft (1) and connected to the sliding tooth sleeve (15). Multiple friction straightening components are arranged in a circumferential array on the anchoring component. The anchoring assembly includes a straightening cylinder (18) and a sliding tooth plate (17). The straightening cylinder (18) is movably mounted on the central shaft (1). Multiple slips (21) are evenly distributed and movably provided on the end of the straightening cylinder (18) away from the lower guide cone (16). The bottom of the slips (21) is provided with a sliding groove A. The inner wall of the straightening cylinder (18) is provided with a groove A along the axial direction. The sliding tooth plate (17) is slidably disposed in the groove A. A leaf spring B (19) is provided on the side of the sliding tooth plate (17) near the straightening cylinder (18). The leaf spring B (19) abuts against the bottom surface of the groove A. Under the elastic force of the leaf spring B (19), the sliding tooth plate (17) meshes with the sliding tooth sleeve (15). A toothed positioning ring (14) is connected to the end of the straightening cylinder (18) near the lower guide cone (16) by a screw D (24). The toothed positioning ring (14) contacts the sliding tooth plate (17). The tensioning and retraction transmission mechanism includes a thrust ring (5), a hinge ring (6), a main spring (8), a main spring seat (9), a slip cone (10), and multiple pusher blocks (7). Multiple sliding grooves B are arranged in a circular array on the central shaft (1), and the sliding grooves B are arranged along the axial direction of the central shaft (1). Multiple pusher blocks (7) are slidably connected to multiple sliding grooves B one by one. The thrust ring (5) and the hinge ring (6) are both fitted on all pusher blocks (7). One end of the slip cone (10) is fitted on the hinge ring (6), and the other end is fitted on the central shaft (1). The main spring (8) and the main spring seat (9) are both fitted on the central shaft (1). One end of the main spring (8) pushes the main spring seat (9) against the step surface inside the slip cone (10), and the other end of the main spring (8) abuts against one end of all pusher blocks (7). The cone surface of the slip cone (10) is provided with multiple slide rails arranged in a circular array, and the multiple slide rails are slidably connected to the slide grooves A at the bottom of the multiple slips (21).

2. The mechanical internal cutting tool for oil well workover as described in claim 1, characterized in that: The lower guide cone (16) is located at one end of the central shaft (1).

3. The mechanical internal cutting tool for oil well workover as described in claim 1, characterized in that: The outer wall of the straightening cylinder (18) is provided with a plurality of grooves B in a circular array, and a plurality of friction straightening components are provided in a corresponding manner at the plurality of grooves B; The friction straightening assembly includes a friction block (13), which is slidably connected to the groove B. The friction block (13) is connected to the bottom surface of the groove B through multiple compression springs (12). Multiple limiting screws (11) are threaded on the straightening cylinder (18) near the groove B. The limiting screws (11) are used to limit the friction block (13) in the radial direction of the central axis (1).

4. The mechanical internal cutting tool for oil well workover tubing as described in claim 1, characterized in that: The cutting mechanism includes multiple cutting components, each of which is correspondingly located in a plurality of grooves B on the central shaft (1).

5. The mechanical internal cutting tool for oil well workover tubing as described in claim 4, characterized in that: The cutting assembly includes a support block (2), a leaf spring A (3), and a blade (4). The support block (2) is rotatably connected to the two side walls of the slide groove B by screw A (20). The blade (4) is rotatably connected to the two side walls of the slide groove B by screw B (22). The arc head of one end of the blade (4) extends into the arc groove at one end of the support block (2). One end of the leaf spring A (3) is connected to the support block (2) by screw C (23), and the other end is pressed on the blade (4).

6. The mechanical internal cutting tool for oil well workover tubing as described in claim 5, characterized in that: The end of the blade (4) away from the support block (2) abuts against the pusher block (7) in the groove B.

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