Stress Analysis of Tubing Thread of the Gas Seal Test in Deep Gas Well

摘要

Seal test of tubing thread in high pressure gas well is a new technology currently, but there is no uniform standard regarding the accurate sealing test pressure, frequently improper sealing test pressure can easily lead to damage and fatigue failure of tubing threads. In order to solve the above problems, in this paper the axisymmetric finite element mechanical model of the BEAR threads based on the theory of elastic-plastic mechanics was established, and the finite element software used to calculate the results. The results showed that when the test pressure was equal to 100 and 50% of the RIP (Resistance to internal pressure) of tubing, the plastic deformation of the tubing thread occurred, and the plastic deformation area generated in the roots of the last three buckle, when the test pressure was equal to 25% of the RIP of the tubing, the maximum stress of all types of tubing threads was less than the yield strength. Based on this model, the stress of the tubing thread of the high-pressure gas well can be quantitatively and fully evaluated, and the gas seal test technology can be provided with theoretical reference.