Failure Analysis of Corrosion and Perforation and Life Prediction of Natural Gas Pipeline

The reasons for corrosion and perforation of a natural gas pipeline in Sichuan province were analyzed by means of on-site investigation, external environment analysis, physical and chemical analysis of soil around pipeline and property testing of failed pipeline. A judgement formula of pipeline corrosion failure was fitted by Matlab software, and a test of verification was carried out. The results show that a part of coating on the outer wall of the failed pipeline was peeled off, and then the pipeline steel was corroded in contact with O₂, CO₂ and H₂O, and the outer wall of the pipeline was also corroded by sulfate reducing bacteria. The pipeline corrosion failure judgment formula had good accuracy,as the error between blasting pressure from calculation by the formula and from the verification test result was small. It was predicted that one of the corrosion pits would be corroded and perforated.