Oil conduit screwed connection structure

Abstract

The invention relates to an oil pipe threaded connection structure, which is formed by screwing an oil pipe end (10) with an outer thread together with a pipe joint (11) with an inner thread. The threads adopted by the oil pipe end (10) and the pipe joint (11) are both approximate trapezoidal tapered threads; the head part of the oil pipe end (10) is provided with a circular arc surface (4); a circular conical surface (3) in interference fit with the circular arc surface is arranged on the pipe joint (11); the head part of the oil pipe end (10) is provided with an outer torque step (8); an inner torque step (7) matched with the outer torque step (8) is arranged on the pipe joint (11); the middle segment of the heat part of the oil pipe end (10) is provided with an outer cylindrical surface (2); an inner cylindrical surface (1) in interference fit with the outer cylindrical surface (2) is arranged on the pipe joint (11). The structure has the advantages of high threaded connection strength, good sealing performance, easy buckling, difficult buckling separation, good thread gluing preventing performance, strong over-torque preventing capability, etc.

Description

technical field [0001] The invention relates to the technical field of threaded connection of oil pipes, in particular to a threaded connection structure of oil pipes. It is mainly used in oil and gas fields in the oil and gas industry, and is used in oil and gas wells requiring high connection strength and sealing performance, such as deep wells, ultra-deep wells, high-pressure gas wells, ultra-high temperature wells, directional wells, and wells with complex formation structures. Background technique [0002] Oil pipe is a special pipe used to form a pipe string for collecting oil and gas medium or liquid injection in oil and gas wells. The tubing string is usually connected by threaded tubing at both ends, and the connection part of the tubing string is the weak point of its performance. In order to ensure the tightness and connection strength of the joint, there are strict requirements on the accuracy of the oil pipe thread. [0003] With the development of oil drillin...

AI Technical Summary

Problems solved by technology

[0004] The API round thread has good liquid sealing performance. The design of the API round thread does not directly contact the top and bottom of the thread of the internal and external threads, which determines that the connection strength of the thread part is only 60-80% of the pipe body part, and because of its There is a leakage channel after the threaded connection, and the sealing effect is generated by blocking the leakage channel with thread grease, so its sealing performance to the gas medium is poor

In addition, the design of the API round thread determines that when the external thread of the tubing is connected to the coupling, there is a distance of 2 J values ​​between the two ends of the coupling. That is, after the API round thread is connected, due to the There is a space in the middle, resulting in a sudden change in the diameter of the inner hole of the pipe and the internal thread of the coupling. This sudden change is likely to generate eddy currents during oil or gas production. If it is used in a well with strong corrosion, it is easy to cause corrosion in this part. cause an accident

[0005] Although the API buttress thread has high connection strength, the sealing performance of the thread is not ideal

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