Control of Top-of-Line Corrosion in a Sour Gas Gathering Pipeline with Corrosion Inhibitors

This paper first reviews laboratory and field investigations of top-of-line  corrosion. A particular oxygen contaminated,  wet sour gathering pipeline is described  which experienced severe corrosion in the vapor zone. Pigging could not be accomplished, therefore a corrosion inhibitor with oxygen tolerance and vapor space capabiltiy was applied.

Corrosion in the line was subsequently monitored with coupons, ultrasonic thickness measurements, and periodic visual inspection. Corrosion inhibitor was detected in gas samples pulled from the line. All indicators pointed to adequate corrosion control in this pipeline even though operated in the same regime as before.