Simulation and analysis of force on connection of casing thread under alternating load of gas storage

Abstract

Underground gas storage as the main system of natural gas peak regulation, its construction demand continues to grow in the world. Different from other common oil and gas well strings, the service time of the gas storage string is longer and the service environment is worse, which poses a greater challenge to the integrity design of the string joint. In this paper, starting from the most important connection and sealing performance of the pipe string joint, aiming at the special threaded joint suitable for the gas storage pipe string, based on the analysis of the force and deformation of the gas storage pipe string, the joint connection strength and sealing performance of the pipe string joint under the axial load, internal and external pressure and long-term alternating load are considered. Based on the FINITE element model of VAM TOP special threaded joint, the deformation and sealing behavior of the joint under different composite loads were numerically simulated, and the variation law of joint connection stress and sealing contact pressure with load was obtained, and the most vulnerable failure position and the most dangerous working condition were analyzed.