Pitting and Uniform Corrosion of X65 Carbon Steel in Sour Corrosion Environments: The Influence of CO2, H2S, and Temperature

Abstract

Localized corrosion of carbon steel pipelines in oilfield environments is a serious concern. In environments containing both CO2 and H2S gases, pitting corrosion of carbon steel is considered to be a common occurrence which is particularly complex and still not fully understood. This paper presents a parametric study investigating the pitting corrosion behavior of carbon steel in CO2-H2S-containing environments. The work presented is divided into two parts. Part one focuses on understanding the impact of changes in three key process parameters (namely: temperature, absence/presence of 10% H2S, and absence/presence of CO2 in the gas phase) on FeS film formation process and overall the corrosion behavior of carbon steel with emphasis on general corrosion of carbon steel in a 3.5 wt% NaCl brine at 30°C and 80°C. Part two focuses on understanding the early and later stages of the pitting corrosion process, with consideration afforded to general corrosion and iron sulfide (FeS) film formation mechanisms, kinet...