Leakage Failure Analysis of the ERW Steel Pipeline

Abstract

This paper provides a thorough investigation on the leakage reason of the ERW steel pipeline in an oil field. Through appearance inspection, physicochemical inspection, metallographic inspection and scanning electron microscope (SEM), it was found that the main reason of corrosions was caused by residual liquid at the bottom of the pipeline and O2 and CO2 in the air pressure test. The corrosion medium was large volume of O2 and CO2 forming continuously saturated corrosive aqueous solution in small volume of residual liquid, and the corrosion type was the under-deposit corrosion. It is recommended to conduct hot air purging on the pipelined before pressure test for building pipelines in the future, and if the pipeline is not put into use in time, it is recommended to use nitrogen to maintain pressure.