Real-time fitness-for-service assessment method for girth weld of oil and gas pipelines subject to geological hazards

Fracture failure of girth weld of high-grade oil and gas pipelines is the most concerning problem of the oil and gas pipeline industry in China. The fracture failure accidents of pipeline girth weld occurred in recent years show that the girth weld fracture is mainly caused by the soil displacement load induced by geological hazards. To ensure pipeline safety, it is necessary to perform an integrity assessment on the defected pipeline girth welds subjected to soil displacement load. Herein, the research achievements of the oil & gas storage and transportation facility safety group from China University of Petroleum (Beijing) in the last decade were integrated, in terms of the pipe-soil interaction in geological hazard regions, the failure mechanism of girth weld and its fitness-for-service assessment method. Meanwhile, the introduction was made to the establishment of the association relationship between soil displacement and girth weld fracture, as well as the systematic method for real-time fitness-for-service assessment of defected pipeline girth weld. Besides, the relevant theory and methods involved in the specific links were also discussed.