Oil bushing threaded joint

Abstract

The invention relates to an oil bushing threaded joint which comprises a coupling and a pipe. The oil bushing threaded joint is characterized in that the coupling is provided with an internal taperedthread, an inner sealing tapered surface with a groove and a reverse stopping circular bead; after the end of the pipe is necked down, a necked-down opening is formed, and the pipe is provided with anexternal tapered thread, an external sealing tapered surface and an oblique end face; the internal tapered thread includes an internal tapered thread tooth bottom, an internal tapered thread bearingsurface, an internal tapered thread tooth top and an internal tapered thread guide surface, wherein the internal tapered thread tooth bottom and the internal tapered thread tooth top are both parallelto the coupling axis; and the external tapered thread includes an external tapered thread guide surface, an external tapered thread tooth top, an external tapered thread bearing surface and an external tapered thread tooth bottom, wherein the external tapered thread tooth top and the external tapered thread tooth bottom are both parallel to the pipe axis. The oil bushing threaded joint has the advantages of the good air-sealing performance and the high connection efficiency, and also has the advantages of being strong in anti-twisting ability and less prone to sticking.

Description

technical field [0001] The invention relates to an oil casing threaded joint, which belongs to the technical field of oil pipe threaded connection. Background technique [0002] Oil casing refers to oil pipe and casing. The outer diameter of oil pipe is generally less than 114.3mm, and the outer diameter of casing is generally greater than 114.3mm but less than 508mm. In the process of exploiting oil and natural gas, hundreds of oil and casing pipes are connected by threaded joints to form a pipe string with a length of thousands of meters. The pipe string bears very complex loads, including internal pressure, external pressure, tension, Due to bending, torsion and temperature loads, the joint is the weakest link in the whole pipe string, and it is easy to cause joint fracture and leakage failure. [0003] At present, most of the joints used in oil casing are API joints. API joints are joints processed and manufactured in accordance with API (American Petroleum Institute) ...

AI Technical Summary

Problems solved by technology

The disadvantages are: 1) After the joint is tightened, there is a gap between the internal and external meshing threads, so the sealing performance is poor, especially the air sealing performance is worse; 2) The stress concentration of the thread is serious, and the non-thickened tubing uses a 10-tooth round thread, This kind of fine-pitch thread is difficult to confirm and is easy to make mistakes, and often fails to stick and buckle, which cannot meet the requirements of multiple loading and unloading

Its disadvantages are: 1) protruding threads are not easy to detect and process

Rely on the protruding thread to block the leakage channel. The processing requirements of the protruding thread are very strict. If the protruding thread is set on one of the 4th to 7th threads of the female thread, it is difficult to detect with existing detection tools.

2) There is a serious stress concentration in the part of the meshing thread

Where the protruding thread and the external tapered thread cooperate, there will be stress concentration, which is unfavorable to the use of the joint

[0006] In addition to the above-mentioned patents, there are many patents that have proposed their own solutions to make up for the defects and deficiencies of API joints. Some optimize the thread shape, some increase the torque shoulder, and some develop special thread compound. Although these technologies are all Achieved certain effects, but also have their own shortcomings, so this technical problem has not been well resolved

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