Localized, rather than uniform corrosion, is the principal cause of failure by CO2 corrosion. Flow-loop experiments were conducted to determine the effect of fatty acids present in many oil and gas production streams on the pitting corrosion of carbon steel in air-free CO2 systems. Independent of pH, increase in acidity and in buffer capacity of the solution adjacent to the metal surface was found to decrease the depth of the pits.
Keywords: CO2 corrosion, fatty acids, buffer capacity.