Observations on the Influences of Dissolved Hydrocarbon Gases and Variable Water Chemistries on Corrosion of an API-L80 Steel

Accelerated electrochemical techniques were used to study the corrosion of carbon steel in laboratory-simulated aqueous environments representing typical produced waters from natural gas production wells. Specifically, the separate and conjoint effects of the various ionic species in the electrolyte, and the influences of dissolved methane and propane on corrosion of the steel were investigated. Tests were performed at temperatures and pressures up to 95 C and 700 kPa, respectively. Some kinetic parameters were evaluated from both anodic and cathodic polarization measurements. The results showed that the reduction of H₂O and HCO₃^– ions is important in explaining the cathodic polarization characteristics. The partial reactions occurring in the system were defined and explained, in part, from theoretical reconstruction of the experimental polarization curves.