Stress Analysis of Premium Tubing Connection with Different Make-Up Torque in Different Well Depth

In high temperature and high pressure gas wells, premium tubing connections often leak, which lead to the problem of casing pressure rise. In order to know the sealing ability of premium tubing connection in different well depth with different loads as well as different make-up torque, a three-dimensional finite element model of a 88.9 mm × 6.45 mm P110 premium tubing connection is established by finite element software. Based on the material nonlinear and elastic-plastic contact analysis module, the Mises stress and contact pressure distribution of sealing surface, torque shoulder and threads of the premium tubing connection near the wellhead and the bottom of the well are analyzed. At the same time, the influence of different make-up torque on the sealing performance of the connection is analyzed. The research shows that for this premium tubing connection, near the wellhead the max make-up torque recommended by the manufacturer should be used to make up the premium connection, so as to ensure a higher contact pressure on the sealing surface and improve the sealing performance of the premium connection. Near the bottom of the well the min make-up torque shall be used to reduce the Mises stress at the threads and ensure the premium connection will not be damaged.