This paper details the processes used to respond to two Top of Line Corrosion (TLC) failures in a sour gas gathering system. The steps used to diagnose and remediate failures, including Root Cause Analysis, modeling of conditions, and changes to operating procedures are presented. The effect of gas cooling rate on water condensation, the pH of the condensed water, and the flow regime in each segment are discussed, as are their effect on the type of corrosion. The effectiveness of batch-filming and continuous inhibition in these lines is presented, as well as changes implemented after the failure incidents to improve corrosion management program effectiveness. Batch filming at proper intervals is shown to be an effective method for preventing TLC.
Keywords: carbon dioxide, corrosive gas, sour gas, hydrogen sulfide, top of line corrosion, condensed water, Root Cause Analysis, modeling, flow regime, pipeline, inhibition