Development of Continuous Application Based Corrosion Inhibitors to Mitigate the Problems Caused by Top of the Line Corrosion in Upstream Oil and Gas Industry

In multiphase wet gas systems with stratified flow, condensation of water and/or hydrocarbon occurs at the top of the line because of a temperature gradient between the internal and external environments of the pipeline. Acidic gases such as carbon dioxide, hydrogen sulfide, and even organic acids may be present in such systems, and they cause a reduction of pH because of their dissolution in the condensed water. In the absence of any buffering agents, this condensed water can cause significant corrosion between the 10 o?clock to 2 o?clock positions, and this deterioration is formally described as top of the line corrosion (TLC). Conventional corrosion inhibitors are transported to the pipeline surface through the produced fluids, and in the absence of turbulence in the pipeline, the effectiveness of conventional continuous inhibitors at the top of the line is drastically reduced. The metal remains unprotected and exposed to these corrosive species resulting in severe damage. Corrosion at the top of the line can severely hamper the safe operation of assets as well as decrease their life of operation, and hence, there is a need for effective chemistries which will mitigate the corrosion issues at the top of the line. This paper describes the development of new, continuous application based, top of the line corrosion inhibitors utilizing an in-house condensation rig for screening applicable candidates. Progress on the development and understanding of applicable chemistries for several generations of TLC inhibitor products will be discussed.