High-torsion-resistance air-tight seal screwed joint

Abstract

A high-torsion-resistance air-tight seal threaded joint relates to the technical field of threaded joints, and comprises an internal threaded joint and an external threaded joint, the internal threaded joint comprises an internal thread main step, an internal thread extension section, an internal thread, an internal thread inclined step, an internal thread cylindrical section and an internal thread auxiliary step; the external thread joint comprises an external thread main step, an external thread extension section, an external thread, an external thread cylindrical section, an external thread inclined step, an external thread cylindrical extension section and an external thread auxiliary step; the taper of 1: 6-1: 16 is adopted for connection of the external threads and the internal threads. When the internal thread joint is connected with the external thread joint, the internal thread inclined step is in interference fit with the external thread inclined step, the internal thread extension section is in clearance fit with the external thread extension section, and the internal thread cylindrical section is in clearance fit with the external thread cylindrical extension section; the three anti-torsion sealing structures are arranged, so that the anti-torsion strength and the sealing performance are improved, the stress concentration of the threads is dispersed, and the requirements of oil and gas field drilling for high anti-torsion strength and high internal pressure of the threads are met.

Description

Technical Field

[0001] The utility model relates to the technical field of threaded joints, in particular to a high-torsion-resistant air-sealed threaded joint. Background Art

[0002] The drill pipe threaded connection plays a crucial role in the entire drill string and is also the weakest point in the entire drill string. According to ISO 11961 and API Spec 5DP, the torsional strength ratio between the threaded connection and the pipe body is generally set at 0.8 or above. However, in actual drilling, excessive torsional strength often leads to failure. As drilling depths in Chinese oil fields increase, the mud and gas pressures applied to the drill string increase, leading to frequent seal failures. Utility Model Content

[0003] In view of the shortcomings of the above-mentioned existing technologies, the purpose of the present invention is to provide a highly torsional airtight threaded joint, which can solve the problem that as the drilling depth of the oil field oil layer becomes deeper and deeper, the mud and gas pressure applied to the drill string becomes greater and greater during the drilling process, and the drill pipe is prone to sealing failure and puncture failure.

[0004] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0005] A highly torsionally resistant, airtight threaded joint comprises an internally threaded joint and an externally threaded joint, wherein the internally threaded joint comprises an internally threaded main step, an internally threaded extension section, an internal thread, an internally threaded oblique step, an internally threaded cylindrical section, and an internally threaded secondary step; the externally threaded joint comprises an externally threaded main step, an externally threaded extension section, an external thread, an externally threaded cylindrical section, an externally threaded oblique step, an externally threaded cylindrical extension section, and an externally threaded secondary step; the external and internal threads are connected using a taper of 1:6-1:16; when the internally threaded joint and the externally threaded joint are connected, the internally threaded oblique step and the externally threaded oblique step have an interference fit, and the internally threaded extension section and the externally threaded extension section, as well as the internally threaded cylindrical section and the externally threaded cylindrical extension section, have a clearance fit.

[0006] Preferably, end faces of the internal thread secondary step and the external thread secondary step are both provided with chamfers.

[0007] Preferably, the thread profiles of the internal thread and the external thread adopt a pitch of 5.08 mm, 6.35 mm, 7.257 mm or 8.567 mm.

[0008] Preferably, the external thread and the internal thread are connected with a taper of 1:12.

[0009] Preferably, the inner and outer diameters of the internal threaded joint are equal to those of the external threaded joint.

[0010] Compared with the existing technology, the beneficial effects of the present invention are as follows: in the present invention, by setting the internal thread main step and the external thread main step, the internal thread inclined step and the external thread inclined step, and the internal thread secondary step and the external thread secondary step, the three anti-torsion sealing structures improve the torsional strength and sealing performance, and disperse the stress concentration of the thread, solving the requirements of oil and gas field drilling for high torsional strength and high internal pressure of the thread. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0012] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0013] Figure 2 This is a schematic diagram of the connection of the internal and external threaded joint of the present invention.

[0014] Description of reference numerals:

[0015] 1-Internal thread joint, 11-Internal thread main step, 12-Internal thread extension section, 13-Internal thread, 14-Internal thread oblique step, 15-Internal thread cylindrical section, 16-Internal thread secondary step, 2-External thread joint, 21-External thread main step, 22-External thread extension section, 23-External thread, 24-External thread cylindrical section, 25-External thread oblique step, 26-External thread cylindrical extension section, 27-External thread secondary step, 3-Chamfer. DETAILED DESCRIPTION

[0016] The following describes the invention of the present invention in detail by way of examples in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Example

[0017] like Figures 1 to 2As shown, the utility model discloses a high-torsion airtight threaded joint, comprising an internal threaded joint 1 and an external threaded joint 2, wherein the inner and outer diameters of the internal threaded joint 1 are equal to the inner and outer diameters of the external threaded joint 2; the internal threaded joint 1 comprises an internal thread main step 11, an internal thread extension section 12, an internal thread 13, an internal thread oblique step 14, an internal thread cylindrical section 15 and an internal thread secondary step 16; the external threaded joint 2 comprises an external thread main step 21, an external thread extension section 22, an external thread 23, an external thread cylindrical section 24, an external thread oblique step 25, an external thread cylindrical extension section 26 and an external thread secondary step 27; the external thread 23 and the internal thread 13 are connected with a taper of 1:6-1:16, preferably a taper of 1:12; the internal thread 13 and the external thread The thread profile of thread 23 adopts a pitch of 5.08mm, 6.35mm, 7.257mm or 8.567mm; when the internal thread joint 1 and the external thread joint 2 are connected, the internal thread inclined step 14 and the external thread inclined step 25 are interference fit, and the internal thread extension section 12 and the external thread extension section 22, and the internal thread cylindrical section 15 and the external thread cylindrical extension section 26 are clearance fit; by setting the internal thread main step 11 and the external thread main step 21 to match, the internal thread inclined step 14 and the external thread inclined step 25 to match, and the internal thread secondary step 16 and the external thread secondary step 27 to match, the three anti-torsion sealing structures improve the torsional strength and sealing performance, and disperse the stress concentration of the thread, solving the demand for high torsional strength and high internal pressure of the thread in oil and gas field drilling. The end faces of the internal thread secondary step 16 and the external thread secondary step 27 are both provided with chamfers 3, which are conducive to smooth mud and no vortex generation.

[0018] Principle of use: The internal thread main step 11 and the external thread main step 21, the internal thread sub-step 16 and the external thread sub-step 27 are connected by threaded connection to transmit torque to generate pressure and squeeze them together: the threaded connection transmits torque to make the internal thread main step 11 and the external thread main step 21 fit together to generate strong resistance which is converted into torsional strength; the threaded connection transmits torque to make the internal thread sub-step 16 and the external thread sub-step 27 fit together to generate resistance which is inferior to the internal thread main step 11 and the external thread main step 21 and is converted into torsional strength; the external thread oblique step 25 is inserted into the internal thread oblique step 14 by generating extrusion through torque, and the strong torque generates an interference fit, and the external thread oblique step 25 and the internal thread oblique step 14 generate higher sealing performance, and have a resistance conversion torque lower than the internal thread sub-step 16 and the external thread sub-step 27.

[0019] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and application concept of the present invention, should be covered by the protection scope of the present invention.

Claims

1. A highly torsional airtight threaded joint, comprising an internal threaded joint (1) and an external threaded joint (2), characterized in that: The internal thread joint (1) comprises an internal thread main step (11), an internal thread extension section (12), an internal thread (13), an internal thread oblique step (14), an internal thread cylindrical section (15) and an internal thread secondary step (16); the external thread joint (2) comprises an external thread main step (21), an external thread extension section (22), an external thread (23), an external thread cylindrical section (24), an external thread oblique step (25), an external thread cylindrical extension section (26) and an external thread secondary step (27); the external thread (23) and the internal thread (13) are connected with a taper of 1:6-1:16; when the internal thread joint (1) and the external thread joint (2) are connected, the internal thread oblique step (14) and the external thread oblique step (25) are interference fit, and the internal thread extension section (12) and the external thread extension section (22), the internal thread cylindrical section (15) and the external thread cylindrical extension section (26) are clearance fit.

2. A highly torsional airtight threaded joint according to claim 1, characterized in that: The end faces of the internal thread secondary step (16) and the external thread secondary step (27) are both provided with chamfers (3).

3. A highly torsional airtight threaded joint according to claim 1, characterized in that: The thread profiles of the internal thread (13) and the external thread (23) adopt a pitch of 5.08 mm, 6.35 mm, 7.257 mm or 8.567 mm.

4. A highly torsional airtight threaded joint according to claim 1, characterized in that: The external thread (23) and the internal thread (13) are connected using a taper of 1:

12.

5. A highly torsional airtight threaded joint according to claim 1, characterized in that: The inner and outer diameters of the internal threaded joint (1) are equal to the inner and outer diameters of the external threaded joint (2).

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