Gas gathering pipelines have played and will continue to play a critical role in safe, reliable transportation of sour gas. Highly corrosive gases and unstable operating conditions in gathering pipelines often contributes and results in serious internal corrosion.
This study focuses on statistical analysis of the in-line inspection (ILI) data on sour gas gathering pipelines to understand the parametric effects on internal corrosion of the pipeline.
The ILI data showed that the bottom of the pipeline does not experience appreciable corrosion. The serious corrosion was observed to always occur at the interface between gas and liquid phases. Studies also showed that internal corrosion defects were more likely to occur on the uphill segment of pipeline than the downhill segment.
Simulations of the flow patterns in the pipelines confirm that the uphill segment has the slug flow pattern which is likely a key factor in causing internal corrosion.