An in-line integrity inspection revealed unusual, yet substantial top of line
corrosion in a low flow, moderately corrosive wet gas pipeline, despite apparently
successful bottom-of-line corrosion control. Following the in-line inspection a
root-cause corrosion investigation was conducted, including further detailed
analysis of the inline inspection data, a failure analysis of pipeline cut-out
samples, and a corrosion modeling assessment using an in-house corrosion
prediction tool. The corrosion modeling prediction, which provided a reasonable
interpretation of where and why corrosion occurred, proved to be a major
element in identifying the cause of the corrosion. Also, the corrosion modeling
was key to identifying needed performance improvements for the pipeline
corrosion control.