Analysis on cracking of repaired tubing used in surface gas injection pipeline in a western oilfield in China

According to the cracking accident of repaired tubing used in surface gas injection pipeline in a western oilfield in China, the cause of the failure tubing was analysed by means of macroscopic analysis, non-destructive testing, chemical analysis, mechanical testing, metallographic examination, macro and micro fracture analysis. Combined with the working environment of the repaired tubing, conclusions were made that the failure cause of the tubing was sulfide stress corrosion cracking (SSCC) and the crack originated from the clamp area of make -and-break test in the outside surface of the tubing. Finally, suggestions and measures for prevention congener failure were put forward.