Residual strength of a casing with corrosion semi-ellipsoid defect in high-sulfur gas wells

There are few studies on the residual strength of semi-ellipsoid defect casing considering the bending moment load in high sulfur gas well. In this paper, a numerical model of a casing with corrosion defects exposed to bending moment is proposed. The effect of the defect positions along the circumference on the residual strength of the casing with bending moment is investigated. Parametric studies highlight that defect size have significant effect on the residual strength of the casing, and the circumferential defect and the axial defect can change the critical internal pressure and the critical axial load. This finding has a significant guidance for residual intensity evaluation of a casing with defect.