Stress identification and gas tightness performance evaluation of casing couplings based on weak magnetic detection technology

At present, the casing leakage problem is still frequent, the new gas sealing buckle has not been completely solved under the influence of complex working conditions and installation errors, and the existing detection means of equipment is a bulky and complicated process. This paper proposes to detect the performance of casing gas sealing based on weak magnetic stress detection technology, aiming to establish a fast and convenient detection method. The research focuses on the p-110 grade TP-G2 casing and establishes a stress-weak magnetic signal detection system, revealing the correlation between the casing’s stress state and the variation of magnetic flux density. The study developed stress distribution models for typical casings under three different gas-tight sealing conditions, analysed the differences in leakage and sealing conditions, and established a mapping relationship between gas-tight performance and stress distribution. Experimental results demonstrate that weak magnetic detection technology can accurately characterise the stress concentration features on the threaded connection sealing end. Through the model, the variations of magnetic flux density, stress distribution, and gas-tight performance for p-110 steel are revealed, providing scientific evidence for stress and sealing performance detection.