Failure Reason of a Subsea Pipeline

A subsea pipeline leaked only after going into operation for three years. The leak reasons were analyzed by means of inspection data analysis, corrosion rate simulation calculation, testing of failed pipe, internal corrosion simulation experiment and corrosion inhibitor effectiveness analysis. The results showed that CO2 and H2S contents were increased in oil after starting production, the effect of corrosion inhibitors was undesirable, thus serious CO2 localized corrosion occured, which was the main reason causing the corrosion failure of the subsea pipeline. Some practical measurements for safe operation of similar subsea pipelines were put forward.