Analysis of Longitudinal Cracks of Casing in Heavy Oil Thermal Recovery Well

Abstract This paper investigates cracking failure of the casing tube. There were longitudinal cracks in heavy oil thermal recovery well occurred an field. The fracture cause was analyzed by macrographic observation, chemical composition analysis, mechanical property test, metallographic scanning electron microscope (SEM) and residual stress calculation. results showed that crack failed originates from external surface pipe has characteristic intergranular propagation. characteristics are brittle fracture. conclusion corrosion cracking(SCC) is main well. Under combined action corrosive media internal stress, SCC generated on casing, propagate along grain boundaries finally lead to casing. Some recommendations proposed avoid similar failures.