Coupling sleeve milling and fishing device and method

Abstract

The present application relates to the technical field of fishing downhole, and is a collar sleeve milling fishing device and method. The former comprises a sleeve milling connector, a leading shoe and a sleeve milling assembly. The leading shoe is fixedly installed on the inner side of the lower end of the sleeve milling connector through a release shear pin. The sleeve milling device is arranged in the sleeve milling connector. The steps of the latter are as follows: (1) selecting the collar sleeve milling fishing device according to the downhole working condition and the size of the collar of the sleeved pipe string. The present application has reasonable and compact structure, and ingenious design. Through the arrangement of the upper inclined surface, the sleeve milling block can better mill the outer side of the lower end of the collar after contacting the lower end surface of the collar, so as to damage the thread between the collar and the oil pipe below the collar. Through the arrangement of the lower inclined surface, the guiding effect is achieved. After the arc-shaped fixed plate contacts the upper end surface of the collar, the sleeve milling assembly is extended outward under the elasticity of the spring sheet, so that the collar can pass through the inside of the sleeve milling connector. The present application has the characteristics of stability, reliability and good milling effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole fishing, and is a coupling sleeve milling fishing device and method. BACKGROUND

[0002] In the production process of an oil and gas well, with the passage of time, the lower pipe string of the oil and gas well may be deformed and blocked due to sand production of the formation, corrosion of the completion fluid on the metal material, metamorphism of the completion fluid, downhole dropouts, pipe string corrosion and the like, affecting the well production, at which time well repair work needs to be performed, and such an accident is generally resolved by first performing sleeve milling and then gradually performing back-off or cutting of the tubing. For a well with severe corrosion, the tubing body may be corroded and perforated or cracked, and the mechanical strength is greatly reduced, so that the tubing body is deformed and broken when fishing under a large pulling force or torque, resulting in fishing failure. In particular, in the repair of an ultra-deep well, the tripping time is long, and the repair construction time is prolonged due to fishing failure, greatly increasing the fishing cost. Compared with the tubing body, the tubing coupling has a large wall thickness, a small length, is not easy to corrode, and has high mechanical strength, and can bear a large load, so that the success rate of fishing can be increased by processing and fishing the tubing coupling.

[0003] At present, the milling fishing device cannot pass through the tubing coupling above the predetermined depth, and cannot directly mill the tubing coupling at the predetermined depth. SUMMARY

[0004] The present application provides a coupling sleeve milling fishing device and method, which overcomes the deficiencies of the prior art, and effectively solves the problem that the existing milling fishing device cannot directly mill the tubing coupling at the predetermined depth.

[0005] One of the technical solutions of the present application is realized by the following measures: a coupling sleeve milling fishing device, comprising a sleeve milling joint, a leading shoe and a sleeve milling assembly, the leading shoe is fixedly installed on the inner side of the lower end of the sleeve milling joint through a release shear pin, a sleeve milling device is arranged in the sleeve milling joint, the sleeve milling device comprises a sleeve milling assembly, a spring sheet, a support seat and an anti-rotation guide piece, a plurality of rectangular large windows are arranged on the outer side of the upper part of the sleeve milling joint at intervals along the circumference, a rectangular small window that can communicate with each large window is arranged on the outer side of the upper part of the sleeve milling joint at the lower middle position of each large window, a sleeve milling assembly is arranged in the sleeve milling joint at the position of each large window, a support seat is fixedly installed on the inner side of the lower part of the sleeve milling joint at the position below the small window through a start shear pin, an anti-rotation guide piece is arranged between the outer side of the support seat and the sleeve milling joint, and the lower part of each sleeve milling assembly is fixedly installed together with the support seat through a spring sheet, and the upper part of the spring sheet is inclined in an upper inner and lower outer shape.

[0006] The following is a further optimization or / and improvement of the above-mentioned one of the technical solutions of the present application:

[0007] The sleeve milling assembly can include a sleeve milling block and an arc-shaped fixing plate, an installation slot is arranged on the inner side of the upper end of the arc-shaped fixing plate, and the sleeve milling block is fixedly installed in the installation slot, the sleeve milling block is in the shape of an arc with an opening facing inward, an upper inclined surface in the shape of a low inner side and a high outer side is arranged on the inner side of the upper end of the sleeve milling block, and a lower inclined surface in the shape of a high inner side and a low outer side is arranged on the inner side of the lower end of the arc-shaped fixing plate.

[0008] The sleeve milling device can further include a countersunk rivet, an upper insertion slot is arranged on the inner side of the lower end of the arc-shaped fixing plate, the upper end of the spring sheet is fixedly installed in the upper insertion slot through the countersunk rivet, a lower insertion slot is arranged on the outer side of the upper end of the support seat corresponding to the position of the upper insertion slot, and the lower end of the spring sheet is fixedly installed in the lower insertion slot through the countersunk rivet.

[0009] The anti-rotation guide can be an anti-rotation guide key block, three large windows are uniformly distributed on the outer side of the upper part of the sleeve milling connector in a circumferential direction at intervals, an anti-rotation guide groove is arranged on the outer side of the lower end of the support seat corresponding to the position between the lower insertion slots of every two adjacent positions, and the anti-rotation guide key block is fixedly installed on the inner side of the sleeve milling connector corresponding to the position of each anti-rotation guide groove and located in the anti-rotation guide groove.

[0010] Hard alloy particles can be inlaid and welded on the upper side and the inner side of each sleeve milling block.

[0011] The upper end and the lower end of the spring sheet can be in the shape of an arc with an opening facing inward.

[0012] The second technical scheme of the present application is realized through the following measures: a method for using the sleeve milling fishing device, including the following steps:

[0013] (1) selecting the sleeve milling fishing device according to the downhole working condition and the size of the sleeve to be sleeved and milled, checking whether the sleeve milling fishing device can pass through the minimum size of the working wellbore, selecting the size of the sleeve milling block according to the connecting sleeve or shoulder of the pipe column to be cut, and connecting the sleeve milling pipe with a sufficient length on the upper part of the sleeve milling fishing device according to the length of the pipe column to be sleeved and milled;

[0014] (2) sequentially fixing and installing the sleeve milling fishing device, the sleeve milling pipe, the variable buckle, the drill pipe and the like from bottom to top and then putting them into the well, and if the sleeved and milled pipe column is stuck by sand, sand or falling objects, it can be rotated and sent;

[0015] (3) in the process of lowering, the lower inclined surface arranged on the inner side of the lower end of the arc-shaped fixing plate first contacts the upper end surface of the sleeve, because the lower inclined surface is a tapered surface with a small upper end and a large lower end, and the sleeve milling assembly is located at the large window position, so that the sleeve milling assembly extends outward under the elasticity of the spring sheet, and the sleeve can pass through the inside of the sleeve milling connector;

[0016] (4) When the predetermined depth is reached, the pipe column is lifted up. The upper inclined surface set on the inner side of the upper end of the sleeve milling block contacts the lower end face of the coupling. The pipe column is lifted up. Under the action of the lower end face of the coupling, the shear pin is started to cut. The sleeve milling device moves down and sits on the upper end face of the guide shoe. At this time, the sleeve milling block is located at the small opening and the sleeve milling block is limited.

[0017] (5) When the tubing string is rotated, the torque is transmitted from the anti-rotation guide to the support seat, so that the milling block rotates relative to the coupling, rotates the tubing string and gives the tubing string a certain lifting force, and the milling block achieves milling of the lower outer side of the coupling, so that the coupling and the tubing connected to its lower part are separated, and then the well is retrieved.

[0018] (6) If the lifting string still cannot lift the fish downhole after a certain period of rotation milling, increase the pulling force of the lifting string to cut the release shear pin, thereby detaching the guide shoe and the milling assembly from the milling joint. The milling joint is then pulled out of the wellhead along with the pipe string that has entered the well, thus releasing the fish.

[0019] This invention features a reasonable and compact structure with ingenious design. By setting a large opening, the milling joint can pass through the coupling during lowering, allowing the milling assembly to extend outward into the large opening under the action of the spring plate, thus avoiding interference with continued lowering to the predetermined depth. By setting a small opening, the milling assembly is limited after the starting shear pin cuts, moving downward with the support base, resulting in better milling performance. By setting an anti-rotation guide, torque is transmitted while preventing the support base from deflecting during descent, thus avoiding misalignment between the milling assembly and the small opening. By setting an upper inclined surface, the outer side of the lower end of the coupling can be better milled after the milling block contacts the lower end face, thereby damaging the threads between the coupling and the oil pipe below. By setting a lower inclined surface, a guiding function is provided, facilitating the milling assembly to extend outward into the large opening under the elasticity of the spring plate after the arc-shaped fixing plate contacts the upper end face of the coupling, allowing the coupling to pass through the inside of the milling joint. This design features stability, reliability, and excellent milling performance. Attached Figure Description

[0020] Appendix Figure 1 These are schematic diagrams of the main half-section structure of embodiments 1 to 6 of the present invention.

[0021] Appendix Figure 2 For the appendix Figure 1 A schematic diagram of the front half-section structure of the middle sleeve milling joint.

[0022] Appendix Figure 3 For the appendix Figure 1 Enlarged front view sectional view of the middle milling assembly.

[0023] Appendix Figure 4 This is a structural diagram of the usage state of Embodiment 7 of the present invention.

[0024] Appendix Figure 5 For the appendix Figure 4Enlarged structural schematic diagram of the main sectional view of the middle coupling.

[0025] The codes in the attached diagram are as follows: 1 is the milling joint, 2 is the guide shoe, 3 is the milling block, 4 is the spring plate, 5 is the support base, 6 is the large opening, 7 is the small opening, 8 is the countersunk rivet, 9 is the anti-rotation guide key block, 10 is the carbide particle, 11 is the upper slot, 12 is the arc-shaped fixing plate, 13 is the upper slope, 14 is the lower slope, 15 is the fish head, 16 is the coupling, 17 is the sleeve, 18 is the oil pipe, 19 is the oil sleeve annulus, 20 is the upper end face of the coupling, 21 is the lower end face of the coupling, 22 is the starting shear pin, 23 is the release shear pin, and 24 is the milling section. Detailed Implementation

[0026] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0027] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0028] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0029] Example 1: As shown in the attached document Figures 1 to 5 As shown, the coupling milling salvage device includes a milling joint 1, a guide shoe 2, and a milling assembly. The guide shoe 2 is fixedly installed on the inner side of the lower end of the milling joint 1 by a release shear pin 23. The milling joint 1 is equipped with a milling device, which includes a milling assembly, a spring plate 4, a support seat 5, and an anti-rotation guide. The upper outer side of the milling joint 1 is provided with several large rectangular windows 6 at intervals along the circumference. The upper outer side of the milling joint 1 corresponding to the middle position of the lower side of each large window 6 is provided with a small rectangular window 7 that can communicate with it. The milling joint 1 is equipped with a milling assembly corresponding to the position of each large window 6. The lower inner side of the milling joint 1 corresponding to the position below the small window 7 is fixedly installed on the lower inner side by a starter shear pin 22. An anti-rotation guide is provided between the outer side of the support seat 5 and the milling joint 1. The lower part of each milling assembly is fixedly installed together with the support seat 5 by a spring plate 4. The upper part of the spring plate 4 is inclined in an upward-inward and downward-outward shape. During use, by setting a large opening 6, the milling sleeve joint 1 can pass through the coupling during the lowering process, allowing the milling sleeve assembly to extend outward into the large opening 6 under the action of the spring plate 4, thus avoiding interference with the continued lowering to the predetermined depth; by setting a small opening 7, the milling sleeve assembly that descends with the support base 5 after being cut by the starting shear pin 22 is limited, thereby achieving a better milling effect; by setting an anti-rotation guide, torque is transmitted while preventing the support base 5 from deflecting during the descent, thus avoiding misalignment between the milling sleeve assembly and the small opening 7.

[0030] The above-mentioned coupling sleeve milling and fishing device can be further optimized and / or improved according to actual needs:

[0031] Example 2: As shown in the attached document Figures 1 to 3 As shown, the milling assembly includes a milling block 3 and an arc-shaped fixing plate 12. The arc-shaped fixing plate 12 has an inner mounting groove on its upper end, in which the milling block 3 is fixedly installed. The milling block 3 is an inwardly opening arc shape. The inner upper end of the milling block 3 has an upper inclined surface 13 that slopes downwards from the inside to the outside, and the inner lower end of the arc-shaped fixing plate 12 has a lower inclined surface 14 that slopes downwards from the inside to the outside. During use, the upper inclined surface 13 allows for better milling of the outer lower end of the coupling after the milling block 3 contacts the lower end face 21, thereby damaging the threads between the coupling and the oil pipe 18 below it. The lower inclined surface 14 acts as a guide, facilitating the milling assembly to extend outwards from the large opening 6 under the elasticity of the spring plate 4 after the arc-shaped fixing plate 12 contacts the upper end face 20 of the coupling, allowing the coupling to pass through the inside of the milling joint 1.

[0032] Example 3: As shown in the attached document Figures 1 to 3 As shown, the milling device also includes countersunk rivets 8. An upper slot 11 is provided on the inner side of the lower end of the arc-shaped fixing plate 12. The upper end of the spring plate 4 is fixedly installed in the upper slot 11 by the countersunk rivets 8. A lower slot is provided on the outer side of the upper end of the support base 5 corresponding to the position of the upper slot 11. The lower end of the spring plate 4 is fixedly installed in the lower slot by the countersunk rivets 8. This arrangement facilitates the fixing of the spring plate 4 during use.

[0033] Example 4: As shown in the appendix Figures 1 to 3 As shown, the anti-rotation guide component is an anti-rotation guide key block 9. Three large openings 6 are evenly distributed circumferentially on the upper outer side of the milling joint 1. Corresponding to each pair of adjacent lower slots, the lower outer side of the support base 5 is provided with an anti-rotation guide groove. An anti-rotation guide key block 9, with its upper end located within the anti-rotation guide groove, is fixedly installed on the inner side of the milling joint 1 at each anti-rotation guide groove position. During use, by setting the anti-rotation guide key block 9, torque can be transmitted, and on the other hand, it serves as an anti-rotation guide, preventing the support base 5 from deflecting during its downward movement and causing misalignment between the milling assembly and the small openings 7.

[0034] Example 5: As shown in the attached document Figures 1 to 3 As shown, each milling block 3 has carbide particles 10 welded to its upper and inner sides. This configuration provides better milling results during use.

[0035] Example 6: As attached Figures 1 to 3 As shown, the upper and lower ends of the spring sheet 4 are both arc-shaped with inward openings. During use, this design allows the ends of the spring sheet 4 to fit against the arc-shaped fixing plate 12 and the support base 5 of the tubular structure, respectively, thus facilitating fixation.

[0036] Example 7: As attached Figures 1 to 5 As shown, a method for using the above-mentioned coupling sleeve milling salvage device includes the following steps:

[0037] (1) Select the coupling milling and fishing device according to the downhole working conditions and the coupling size of the milling string, and verify whether the coupling milling and fishing device can pass through the minimum size of the working well. Select the size of the milling block 3 according to the connecting coupling or shoulder of the cut string. Connect a milling pipe of sufficient length to the upper part of the coupling milling and fishing device according to the length of the string to be milled and fished.

[0038] (2) After fixing and installing the coupling milling and fishing device, milling pipe, variable coupling, drill pipe, etc. together from bottom to top, it is inserted into the well. If the milling and fishing string is buried in sand, stuck in sand, or stuck by falling objects, it can be rotated and sent in.

[0039] (3) During the lowering process, the lower inclined surface 14 provided on the inner side of the lower end of the arc-shaped fixing plate 12 first contacts the upper end surface 20 of the coupling. Since the lower inclined surface 14 is an inner conical surface with a smaller upper part and a larger lower part, and the milling assembly is located at the position of the large opening 6, the milling assembly extends outward to avoid the spring plate 4 under the elasticity, so that the coupling can pass through the inside of the milling joint 1.

[0040] (4) When the predetermined depth is reached, the pipe column is lifted up. The upper inclined surface 13 set on the inner side of the upper end of the sleeve milling block 3 contacts the lower end face 21 of the coupling. The pipe column is lifted up. Under the action of the lower end face 21 of the coupling, the shear pin 22 is activated to cut. The sleeve milling device moves down and sits on the upper end face of the guide shoe 2. At this time, the sleeve milling block 3 is located at the small opening 7 and the sleeve milling block 3 is limited.

[0041] (5) When rotating the tubing, the torque is transmitted from the anti-rotation guide to the support 5, thereby causing the milling block 3 to rotate relative to the coupling, rotating the tubing and giving the tubing a certain upward force. The milling block 3 achieves the connection of the lower outer side of the coupling 16 (as shown in the attached figure). Figure 5 The milling of section 24 (as shown in the milling section) separates the coupling 16 from the oil pipe 18 connected to its lower part, thereby allowing it to be retrieved from the well.

[0042] (6) If the lifting string still cannot lift the fish downhole after a certain period of rotation milling, the pulling force of the lifting string is increased to cut the release shear 23, thereby realizing that the guide shoe 2 and the milling assembly are both separated from the milling joint 1, and the milling joint 1 is pulled out of the wellhead along with the pipe string that has entered the well, thus realizing the release.

[0043] During use, the present invention can pass through multiple tubing couplings 16 and directly mill the tubing couplings 16 at a predetermined depth, effectively solving the problem that the tubing couplings 16 are difficult to mill due to their large wall thickness, short length, resistance to corrosion, high mechanical strength, and ability to withstand large loads, thereby improving the salvage rate.

[0044] The above technical features constitute the best embodiments of the present application, which have strong adaptability and optimal implementation effects. Non-essential technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A collar mill fishing device characterized by The application relates to a sleeve milling joint, a leading shoe and a sleeve milling assembly, the lower inner side of the sleeve milling joint is fixedly provided with the leading shoe through a releasing shear pin, a sleeve milling device is arranged in the sleeve milling joint, the sleeve milling device comprises a sleeve milling assembly, spring sheets, supporting seats and anti-rotation guide pieces, a plurality of rectangular large windows are arranged on the upper outer side of the sleeve milling joint at intervals along the circumference, a small window in a rectangular shape which can communicate with each large window is arranged on the upper outer side of the sleeve milling joint at the middle position of the lower side of each large window, the sleeve milling assembly is arranged in the sleeve milling joint at the position of each large window, the supporting seat is fixedly arranged on the lower inner side of the sleeve milling joint at the position below the small window through a starting shear pin, the anti-rotation guide piece is arranged between the outer side of the supporting seat and the sleeve milling joint, the lower part of each sleeve milling assembly is fixedly arranged with the supporting seat through the spring sheet, and the upper part of the spring sheet is inclined in an upper inner lower outer shape.

2. The collar mill fishing device of claim 1, wherein The sleeve milling assembly comprises a sleeve milling block and an arc-shaped fixing plate, the inner side of the upper end of the arc-shaped fixing plate is provided with a mounting groove, the sleeve milling block is fixedly arranged in the mounting groove, the sleeve milling block is in a circular arc shape with an opening directed inwards, the inner side of the upper end of the sleeve milling block is provided with an upper inclined surface which is inclined in an inner low outer high shape, and the inner side of the lower end of the arc-shaped fixing plate is provided with a lower inclined surface which is inclined in an inner high outer low shape.

3. The collar mill fishing device of claim 2, wherein The sleeve milling device further comprises a countersunk rivet, the inner side of the lower end of the arc-shaped fixing plate is provided with an upper insertion groove, the upper end of the spring sheet is fixedly arranged in the upper insertion groove through the countersunk rivet, the outer side of the upper end of the supporting seat at the position of the upper insertion groove is provided with a lower insertion groove, and the lower end of the spring sheet is fixedly arranged in the lower insertion groove through the countersunk rivet.

4. The collar mill fishing device of claim 1 or 2 or 3, wherein The anti-rotation guide piece is an anti-rotation guide key block, three large windows are arranged on the upper outer side of the sleeve milling joint at intervals along the circumference, the anti-rotation guide groove is arranged on the outer side of the lower end of the supporting seat at the position between the lower insertion grooves of every two adjacent positions, and the anti-rotation guide key block is fixedly arranged in the anti-rotation guide groove on the inner side of the sleeve milling joint at the position of each anti-rotation guide groove.

5. The collar mill fishing device of claims 2 or 3, wherein Hard alloy particles are inlaid and welded on the upper side and the inner side of each sleeve milling block.

6. The collar mill fishing device of claims 1 or 2 or 3, wherein The upper end and the lower end of the spring sheet are in a circular arc shape with an opening directed inwards.

7. The collar mill fishing device of claim 4, wherein The upper end and the lower end of the spring sheet are in a circular arc shape with an opening directed inwards.

8. The collar mill fishing device of claim 5, wherein The upper end and the lower end of the spring sheet are in a circular arc shape with an opening directed inwards.

9. A method of using a collar mill fishing device as claimed in any one of claims 2 to 8, characterised in that The steps are as follows: The collar sleeve milling fishing device is selected according to the downhole working condition and the size of the collar of the sleeved pipe column, the minimum size of the working borehole is used to check whether the collar sleeve milling fishing device can pass, the size of the sleeve milling block is selected according to the connecting collar or the shoulder of the cut pipe column, and the sleeve milling pipe with sufficient length is connected to the upper part of the collar sleeve milling fishing device according to the length of the pipe column to be prepared for sleeve milling fishing; The collar sleeve milling fishing device, the sleeve milling pipe, the variable buckle and the drill pipe are fixedly arranged from bottom to top and then are lowered into the well, and the sleeved pipe column is rotated and sent in if the sleeved pipe column is stuck by sand, sand or falling objects; During the lowering process, the lower inclined surface arranged on the inner side of the lower end of the arc-shaped fixing plate first contacts the upper end surface of the collar, the lower inclined surface is a small upper large lower inner tapered surface, and the sleeve milling assembly is located at the position of the large window, so that the sleeve milling assembly is elastically extended outward to avoid the sleeve milling assembly under the elasticity of the spring sheet, and the collar can pass through the inside of the sleeve milling joint. When reaching the predetermined depth, the pipe string is pulled up, the upper inclined surface arranged on the inner side of the upper end of the milling block contacts the lower end surface of the coupling, the pipe string is continuously pulled up, the shear pin is cut off under the action of the lower end surface of the coupling, the milling device moves down and seats on the upper end surface of the guide shoe, at this time the milling block is located at the small window and achieves the limiting of the milling block; When rotating the pipe string, the torque is transmitted from the anti-rotation guide to the support seat, so that the milling block rotates relative to the coupling, the pipe string is rotated and a certain pulling force is applied to the pipe string, the milling block mills the lower outer side of the coupling, the coupling and the tubing connected below are separated, and then the well is fished out; If the pipe string cannot be pulled up after rotating and milling for a certain time, the pulling force of the pipe string is increased, the shear pin is cut off, so that the guide shoe and the milling assembly are separated from the milling joint, the milling joint is pulled out of the wellhead with the pipe string into the well, and the release is achieved.

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