Evaluation of Tubing Integrity with Rectangular Corrosion under Thermo-Chemical-Mechanical Coupling

This study presents a comprehensive mechanical analysis of P110S oil tubing subjected to thermal and chemical coupling effects, with particular attention to the presence of rectangular corrosion defects. Drawing on the material’s stress–strain constitutive behavior, thermal expansion coefficient, thermal conductivity, and electrochemical test data, the research incorporates geometric nonlinearities arising from large deformations induced by corrosion. A detailed three-dimensional finite element (FE) model of the corroded P110S tubing is developed to simulate its response under complex loading conditions. The proposed model is rigorously validated through full-scale burst experiments and analytical calculations based on theoretical formulations. Building upon this validation, the Extended Finite Element Method (XFEM) and a failure criterion grounded in damage evolution mechanics are applied to investigate the mechanical behavior of the tubing under the coupled influences of temperature, stress, and chemical corrosion. Special emphasis is placed on the role of rectangular corrosion features in determining failure mechanisms. To further elucidate the impact of multiple interacting parameters, a sensitivity analysis is performed by integrating grey correlation theory with simulation outcomes. Based on these findings, the study systematically explores the elastic–plastic deformation process, crack initiation and propagation behavior, and the burst failure response of tubing specimens with varying axial lengths and depths of corrosion. The proposed methodology provides a robust predictive framework for petroleum engineers to evaluate fracture pressure, diagnose failure modes, assess operational risks, and optimize production strategies.