A gas-tight buckle assembly

Abstract

This application provides a gas-tight coupling assembly, belonging to the field of oil casing technology, including an oil pipe and a casing; the outer peripheral wall of the end of the oil pipe has a tapered external thread with a taper of 30°; the inside of the casing has a tapered internal thread that mates with the tapered external thread; the casing has a torque-reversing shoulder at the small end position of the tapered internal thread, the torque-reversing shoulder being a tapered structure with a taper of 15°, and the end of the oil pipe has a concave structure that contacts the torque-reversing shoulder; wherein, the connection position between the torque-reversing shoulder and the small end of the tapered internal thread has a clearance groove, and a gap is formed between the clearance groove and the small end of the tapered external thread; through the above-mentioned configuration of this application, the impact between the tapered external thread at the small end position of the oil pipe and the tapered internal thread of the casing can be reduced, thereby reducing the possibility of damage to the tapered external thread at the small end of the oil pipe.

Description

Technical Field

[0001] This application belongs to the field of oil casing technology, specifically relating to a gas-tight coupling assembly. Background Technology

[0002] Gas-tight special thread is a special thread connection technology designed specifically for the oil and gas industry. It achieves efficient sealing in high-pressure gas or liquid environments through precision structure and materials to prevent leakage. The thread of the gas-tight special thread is a tapered thread, which is suitable for oil tubing in medium and deep wells and gas wells and has good air tightness.

[0003] In the prior art, when the special gas-tight fastener is connected to the oil pipe, the anti-torque shoulder on the special gas-tight fastener limits the end of the oil pipe to ensure the installation position of the oil pipe and the special gas-tight fastener.

[0004] In the existing technology, after the gas-tight special thread is connected to the tubing, the position where the end of the tubing contacts the anti-torque shoulder of the gas-tight special thread is defined as the connection position. The connection position is the small end of the tubing tapered thread, which has poor impact resistance. Under the complex working conditions of running and completing well tools, the tool may collide with the connection position, which can easily lead to damage to the threads of the tubing at the connection position. Utility Model Content

[0005] This application provides a gas-tight fastener assembly, which aims to solve the technical problem that the threads at the small end of the oil pipe are prone to damage in the prior art.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0007] A hermetically sealed buckle assembly is provided, comprising:

[0008] The tubing has a tapered external thread on the outer circumferential wall at the end, with a taper of 30°.

[0009] The casing has a tapered internal thread that mates with a tapered external thread; the casing has a torque-reversing shoulder at the small end of the tapered internal thread, the torque-reversing shoulder being a tapered structure with a taper of 15°, and the end of the tubing has a concave structure that contacts the torque-reversing shoulder.

[0010] The anti-torque shoulder has a clearance groove at the connection position with the small end of the tapered internal thread, and a gap is formed between the clearance groove and the small end of the tapered external thread.

[0011] In one possible implementation, the clearance groove includes a straight section and a tapered section, wherein the angle between the inner peripheral wall of the tapered section and the outer peripheral wall of the tapered external thread is 20°.

[0012] In one possible implementation, the threads of the tapered external thread are inclined on both sides, with the side of the thread facing the small end inclined towards the large end at an angle of 10°; and the side of the thread facing the large end inclined towards the large end at an angle of 3°.

[0013] In one possible implementation, there is a gap between the crest of the tapered external thread and the root wall of the tapered internal thread to reduce sticking.

[0014] In one possible implementation, the inner peripheral wall of the casing between the two anti-torque shoulders is coplanar with the inner peripheral wall of the tubing to reduce the generation of eddies in the fluid within the casing.

[0015] In one possible implementation, the inner circumferential wall between the end of the casing and the large end of the tapered internal thread is a smooth section, so that after the casing is connected to the oil pipe, the tapered external thread is entirely located inside the casing.

[0016] In one possible implementation, the smooth section of the casing has an annular cavity, the top wall of which communicates with the end of the casing; a sealing ring is provided inside the annular cavity, and the inner peripheral wall of the sealing ring abuts against the outer peripheral wall of the tubing.

[0017] The annular cavity has an internal thread near the top of the sleeve, and a retaining ring is provided inside the annular cavity. The retaining ring has an external thread that mates with the thread of the annular cavity; the bottom end of the retaining ring can abut against the sealing ring.

[0018] In one possible implementation, the sealing ring includes an inner support ring and an outer rubber ring; the outer peripheral wall of the oil pipe has an annular groove, and the inner peripheral wall of the outer rubber ring can be located within the annular groove.

[0019] In one possible implementation, the tubing and the annular groove have a tapered guide surface on the side facing the tapered internal thread, so that the outer rubber ring can slide from the end of the sleeve into the annular groove.

[0020] In one possible implementation, the top of the clamping ring has a handle, the diameter of which is less than or equal to the diameter of the top of the sleeve; the outer peripheral wall of the handle has a number of spaced notches to facilitate rotation of the handle.

[0021] This application provides a gas-tight fastening assembly. Compared with the prior art, after the tubing and casing are connected, the tapered external thread and tapered internal thread mesh, and the sealing purpose can be achieved through the mutual contact of the sides of the tapered external thread and tapered internal thread. The concave structure at the end of the tubing contacts the anti-torque shoulder, which can enhance the sealing effect. By setting a relief groove between the anti-torque shoulder and the tapered internal thread, after the tubing and casing are connected in place, the tapered external thread at the small end of the tubing is located in the relief groove, which can reduce the impact between the tapered external thread at the small end of the tubing and the tapered internal thread of the casing, thereby reducing the possibility of damage to the tapered external thread at the small end of the tubing. Attached Figure Description

[0022] Figure 1 A schematic diagram of a hermetically sealed buckle assembly provided in an embodiment of this application;

[0023] Figure 2 A cross-sectional view of a hermetically sealed buckle assembly provided in an embodiment of this application;

[0024] Figure 3 for Figure 2 Enlarged diagram of section A in the middle;

[0025] Figure 4 A schematic diagram of the thread bearing surface and thread guide surface of a hermetically sealed fastener assembly provided in this application embodiment;

[0026] Figure 5 A cross-sectional view of the sleeve portion of a hermetically sealed buckle assembly provided in an embodiment of this application;

[0027] Figure 6 for Figure 5 Enlarged diagram of section B in the middle;

[0028] Figure 7 A cross-sectional view of the handle portion of a hermetically sealed fastener assembly provided in an embodiment of this application;

[0029] Figure 8 for Figure 7 Enlarged diagram of section C;

[0030] Figure 9 This is a schematic diagram of the annular groove portion of a hermetically sealed fastener assembly provided in an embodiment of this application.

[0031] Explanation of reference numerals in the attached drawings: 1. Oil pipe; 11. Concave structure; 12. Annular groove; 13. Conical guide surface; 2. Casing; 21. Smooth section; 22. Annular cavity; 3. Anti-torque shoulder; 31. Clearance groove; 311. Straight section; 312. Conical section; 4. Tooth-shaped guide surface; 5. Tooth-shaped bearing surface; 6. Sealing ring; 61. Inner support ring; 62. Outer rubber ring; 7. Anchor ring; 71. Handle; 72. Notch. Detailed Implementation

[0032] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0033] Please refer to the following: Figures 1 to 9 The present application provides a gas-tight fastening assembly. The gas-tight fastening assembly includes an oil pipe 1 and a sleeve 2. The outer peripheral wall of the end of the oil pipe 1 has a tapered external thread with a taper of 30°. The sleeve 2 has a tapered internal thread that mates with the tapered external thread. The sleeve 2 has a torque-reversing shoulder 3 at the small end of the tapered internal thread. The torque-reversing shoulder 3 is a tapered structure with a taper of 15°. The end of the oil pipe 1 has a concave structure 11 that contacts the torque-reversing shoulder 3. A clearance groove 31 is provided at the connection point between the torque-reversing shoulder 3 and the small end of the tapered internal thread, forming a gap between the clearance groove 31 and the small end of the tapered external thread.

[0034] The gas-tight fastener assembly provided in this application, compared with the prior art, after the oil pipe 1 and the casing 2 are connected, the tapered external thread and the tapered internal thread mesh, and the sealing purpose can be achieved through the mutual contact of the sides of the tapered external thread and the tapered internal thread; the concave structure 11 at the end of the oil pipe 1 contacts the anti-torque shoulder 3, which can play a role in strengthening the sealing; by setting a relief groove 31 between the anti-torque shoulder 3 and the tapered internal thread, after the oil pipe 1 and the casing 2 are connected in place, the tapered external thread at the small end of the oil pipe 1 is located in the relief groove 31, which can reduce the impact between the tapered external thread at the small end of the oil pipe 1 and the tapered internal thread of the casing 2, thereby reducing the possibility of damage to the tapered external thread at the small end of the oil pipe 1.

[0035] It should be noted that in oil and gas drilling and completion operations, various tools (such as drill pipe, drill collar, casing, etc.) need to be frequently lifted from the wellhead or lowered into the well. This process is called "tripping and lowering operations". Completion tools usually include various equipment used for downhole operations, such as packers, bridge plugs, perforating guns, etc.

[0036] The anti-torque shoulder 3 provides positive torque stop, thus ensuring accurate upper torque; the tapered setting of the anti-torque shoulder 3 can disperse circumferential stress, thus reducing circumferential stress at the small end of the joint after the tubing 1 is connected to the casing 2.

[0037] By cooperating with the concave structure 11 on the oil pipe 1, the tapered design of the anti-torque shoulder 3 can disperse the impact after the tool collides with the inner peripheral wall of the anti-torque shoulder 3, reducing the damage to the tapered external thread at the small end of the oil pipe 1.

[0038] The pitch of the tapered external thread and the tapered internal thread is 4 threads / in. In this application, the outer diameter of the sleeve 2 is greater than or equal to 244.48 mm.

[0039] In some embodiments, such as Figures 1 to 9 As shown, the clearance groove 31 includes a straight cylindrical section 311 and a tapered cylindrical section 312, and the angle between the inner peripheral wall of the tapered cylindrical section 312 and the outer peripheral wall of the tapered external thread is 20°.

[0040] The tapered section 312 of the clearance groove 31 can gradually increase the distance between the inner peripheral wall of the clearance groove 31 and the outer peripheral wall of the tapered external thread; the straight section 311 of the clearance groove 31 can control the distance between the clearance groove 31 and the tapered external thread within a reasonable range, so as to avoid the tapered section 312 extending too far and affecting the thread fit between the tubing 1 and the casing 2.

[0041] By setting the taper of the tapered section 312 to 20°, the distance between the tapered section 312 and the tapered external thread can be increased. When the distance between the tapered section 312 and the tapered external thread is within one or two pitch ranges, the straight section 311 restricts the continued outward expansion of the tapered section 312, thus limiting the range of the clearance groove 31 to one or two pitch ranges.

[0042] In some embodiments, such as Figures 1 to 9 As shown, the threads of the tapered external thread are inclined on both sides. The side of the thread facing the small end is inclined towards the large end at an angle of 10°; the side of the thread facing the large end is inclined towards the large end at an angle of 3°.

[0043] The side of the thread facing the small end is the thread guide surface 4, with an angle of 10°, which is consistent with the angle of the conventional API trapezoidal thread, making it easy to identify the thread. The side of the thread facing the large end is the thread bearing surface 5, which is designed at 3° to reduce the occurrence of thread slippage failure and improve the reliability of the threaded connection.

[0044] In some embodiments, such as Figures 1 to 9 As shown, there is a gap between the top of the thread teeth of the tapered external thread and the bottom wall of the root of the tapered internal thread to reduce sticking.

[0045] By setting a gap between the tooth tip of the tapered external thread and the tooth root wall of the tapered internal thread, the tooth tip of the tapered external thread will not contact the tooth root wall of the tapered internal thread during the tightening process. This reduces wear on the tooth tip and tooth root, thereby reducing the occurrence of seizing.

[0046] In some embodiments, such as Figures 1 to 9As shown, the inner circumferential wall between the two anti-torque shoulders 3 inside the casing 2 is the sealing surface. The sealing surface is coplanar with the inner circumferential wall of the oil pipe 1 to reduce the eddy current phenomenon generated by the fluid inside the casing 2.

[0047] With the above configuration, the two anti-torque shoulders 3 inside the casing 2 are connected together, and the inner peripheral wall of the connection position is coplanar with the inner peripheral wall of the oil pipe 1. When the fluid flows through the connection position of the two oil pipes 1, the diameter difference between the two oil pipes 1 at the connection position can be reduced, thereby reducing the occurrence of eddies in the fluid at the connection position of the two oil pipes 1.

[0048] After the two anti-torque shoulders 3 are connected together, the connection between the anti-torque shoulders 3 and the sleeve 2 can be enhanced, the mechanical properties of the anti-torque shoulders 3 can be improved, and the occurrence of damage to the anti-torque shoulders 3 can be reduced.

[0049] In some embodiments, such as Figures 1 to 9 As shown, the inner circumferential wall between the end of the casing 2 and the large end of the tapered internal thread is a smooth section 21, so that after the casing 2 is connected to the oil pipe 1, the tapered external thread is completely located inside the casing 2.

[0050] By setting a smooth section 21 inside the casing 2, after the oil pipe 1 and the casing 2 are threaded together, all the tapered external threads on the oil pipe 1 can be set inside the casing 2. That is, the tapered external threads on the oil pipe 1 are hidden inside the casing 2, which can protect the tapered external threads of the oil pipe 1 and make the tapered external threads mate with the tapered internal threads of the casing 2 as much as possible, thereby improving the tensile strength.

[0051] Compared to the design where part of the tapered external thread on tubing 1 is located outside casing 2, the above-mentioned design in this application can protect the tapered external thread on tubing 1 and reduce damage to the tapered external thread on tubing 1.

[0052] In some embodiments, such as Figures 1 to 9 As shown, the smooth section 21 of the casing 2 has an annular cavity 22, the top wall of the annular cavity 22 is connected to the end of the casing 2; a sealing ring 6 is provided in the annular cavity 22, and the inner peripheral wall of the sealing ring 6 abuts against the outer peripheral wall of the oil pipe 1.

[0053] With the above configuration, the outer peripheral wall of the sealing ring 6 abuts against the inner peripheral wall of the annular cavity 22, and the inner peripheral wall of the sealing ring 6 abuts against the outer peripheral wall of the oil pipe 1, which can play a secondary sealing role and reduce the leakage of fluid in the oil pipe 1.

[0054] In order to fix the position of the sealing ring 6, a retaining ring 7 is provided in the annular cavity 22; the annular cavity 22 has an internal thread near the top of the sleeve 2, and the retaining ring 7 is provided in the annular cavity 22. The retaining ring 7 has an external thread that mates with the thread of the annular cavity 22; the bottom end of the retaining ring 7 can abut against the sealing ring 6.

[0055] By providing an external thread on the outer peripheral wall of the clamping ring 7 and an internal thread in the annular cavity 22, the clamping ring 7 and the annular cavity 22 can be threadedly engaged. After the clamping ring 7 is installed in place, the bottom of the clamping ring 7 can abut against the sealing ring 6, and the bottom of the sealing ring 6 can abut against the bottom wall of the annular cavity 22, thus confining the sealing ring 6 within the annular cavity 22.

[0056] When leakage occurs at the connection between the tapered external thread and the tapered internal thread, the sealing ring 6 at the position of the annular cavity 22 can play a secondary sealing role, reducing the leakage of fluid from the sleeve 2.

[0057] By pressing the sealing ring 6 against the inner circumferential wall of the annular cavity 22 and the outer circumferential wall of the oil pipe 1, the gap between the casing 2 and the oil pipe 1 at the position of the annular cavity 22 can be filled, thereby achieving a sealing effect.

[0058] In some embodiments, such as Figures 1 to 9 As shown, the sealing ring 6 includes an inner support ring 61 and an outer rubber ring 62; the outer peripheral wall of the oil pipe 1 has an annular groove 12, and the inner peripheral wall of the outer rubber ring 62 can be located within the annular groove 12.

[0059] The inner support ring 61 is made of metal, the outer rubber ring 62 is made of rubber, and the sealing ring 6 is processed by vulcanization.

[0060] By setting the inner support ring 61, the overall strength of the sealing ring 6 can be improved; by setting the outer rubber ring 62, it mainly plays a sealing role; after installation, part of the sealing ring 6 is located in the annular groove 12 and the other part is located in the annular cavity 22, so it can seal the gap between the casing 2 and the oil pipe 1.

[0061] After the annular groove 12 is provided on the outer peripheral wall of the oil pipe 1, a part of the outer rubber ring 62 can be located in the annular groove 12; when the fluid leaks to the position of the outer rubber ring 62, the fluid applies pressure to the outer rubber ring 62, and the outer rubber ring 62 can press against the annular groove 12, thus improving the secondary sealing performance of the sealing ring 6.

[0062] In some embodiments, such as Figures 1 to 9 As shown, the tubing 1 has a tapered guide surface 13 on the side of the annular groove 12 facing the tapered internal thread, so that the outer rubber ring 62 can slide from the end of the sleeve 2 into the annular groove 12.

[0063] By providing a tapered guide surface 13 on the oil pipe 1, when the sealing ring 6 is removed from the oil pipe 1, the outer rubber ring 62 on the sealing ring 6 can deform along the tapered guide surface 13, then slide onto the outer peripheral wall of the oil pipe 1, and finally slide out from the tapered external thread position at the end of the oil pipe 1.

[0064] During installation, first, the clamping ring 7 is fitted onto the oil pipe 1, and then the sealing ring 6 is fitted onto the oil pipe 1. At this time, the sealing ring 6 can be slid to the position of the annular groove 12. Then, the oil pipe 1 and the sleeve 2 are threaded together. After the oil pipe 1 and the sleeve 2 are threaded together, the sealing ring 6 is squeezed between the annular groove 12 and the annular cavity 22, which plays a preliminary role in restricting the sealing ring 6.

[0065] Sliding the clamping ring 7 into the annular cavity 22 and threading the clamping ring 7 into the annular cavity 22 allows the clamping ring 7 to press against the sealing ring 6, thus finally restricting the position of the sealing ring 6 and enabling the sealing ring 6 to seal the gap between the casing 2 and the oil pipe 1.

[0066] In some embodiments, such as Figures 1 to 9 As shown, the top of the clamping ring 7 has a handle 71, the diameter of which is less than or equal to the diameter of the top of the sleeve 2; the outer peripheral wall of the handle 71 has several notches 72 spaced apart to facilitate the rotation of the handle 71.

[0067] This embodiment is illustrated by taking the case where the diameter of the handle 71 is the same as the top diameter of the sleeve 2. By setting the handle 71 on the clamping ring 7 and setting the notch 72 on the handle 71, it is convenient for the operator to rotate the handle 71, thereby making the clamping ring 7 press against the sealing ring 6. When tightening the handle 71, the operator can apply torque to the handle 71 with a tool.

[0068] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A gas-tight clasp assembly, characterized in that, include: The tubing has a tapered external thread on the outer circumferential wall at the end, with a taper of 30°. The casing has a tapered internal thread that mates with a tapered external thread; the casing has a torque-reversing shoulder at the small end of the tapered internal thread, the torque-reversing shoulder being a tapered structure with a taper of 15°, and the end of the tubing has a concave structure that contacts the torque-reversing shoulder. The anti-torque shoulder has a clearance groove at the connection position with the small end of the tapered internal thread, and a gap is formed between the clearance groove and the small end of the tapered external thread.

2. A gas-tight clasp assembly as defined in claim 1, wherein, The clearance groove includes a straight section and a tapered section, and the angle between the inner circumferential wall of the tapered section and the outer circumferential wall of the tapered external thread is 20°.

3. A gas-tight clasp assembly as defined in claim 1, wherein, The tapered external thread has its threads inclined on both sides. The side of the thread facing the small end is inclined towards the large end at an angle of 10°, and the side of the thread facing the large end is inclined towards the large end at an angle of 3°.

4. A gas-tight clasp assembly as defined in claim 1, wherein, The tapered external thread has a gap between the tooth crest and the tooth root bottom wall of the tapered internal thread to reduce sticking.

5. A gas-tight clasp assembly as defined in claim 1, wherein, The inner circumferential wall of the casing between the two anti-torque shoulders is coplanar with the inner circumferential wall of the tubing to reduce the eddy current phenomenon generated by the fluid in the casing.

6. A gas-tight clasp assembly as defined in claim 1, wherein, The inner circumferential wall between the end of the casing and the large end of the tapered internal thread is a smooth section, so that after the casing is connected to the oil pipe, the tapered external thread is completely located inside the casing.

7. A gas-tight clasp assembly as defined in claim 6, wherein, The smooth section of the casing has an annular cavity, the top wall of which is connected to the end of the casing; a sealing ring is provided inside the annular cavity, and the inner peripheral wall of the sealing ring abuts against the outer peripheral wall of the tubing. The annular cavity has an internal thread near the top of the sleeve, and a retaining ring is provided inside the annular cavity. The retaining ring has an external thread that mates with the thread of the annular cavity; the bottom end of the retaining ring can abut against the sealing ring.

8. A gas-tight clasp assembly as defined in claim 7, wherein, The sealing ring includes an inner support ring and an outer rubber ring; the outer peripheral wall of the oil pipe has an annular groove, and the inner peripheral wall of the outer rubber ring can be located within the annular groove.

9. A gas-tight clasp assembly as defined in claim 8, wherein, The tubing and the annular groove have a tapered guide surface on the side facing the tapered internal thread, so that the outer rubber ring can slide from the end of the sleeve into the annular groove.

10. A gas-tight clasp assembly as defined in claim 7, wherein, The top of the clamping ring has a handle, the diameter of which is less than or equal to the diameter of the top of the sleeve; the outer peripheral wall of the handle has several notches spaced apart to facilitate rotation of the handle.

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