Corrosion Inhibitor Performance: Challenges in Low Temperature Conditions

Abstract Application of corrosion inhibitors as remedy to the corrosion of carbon steel pipelines has been a common practice in the oil and gas industry. Availability and lower life cycle cost of carbon steel and corrosion inhibitor combination over corrosion resistant alloys make such inhibitors the preferred corrosion control option of the users. Many examples of corrosion inhibitors for a wide range of temperatures, acid gas pressures and aqueous phase properties are available in literature. Generally, the higher the application temperature, more challenging for an inhibitor to perform, especially beyond 100°C. Mostly corrosion inhibitors are evaluated at temperatures 25°C and above. However, application conditions with temperatures as low as 12°C exist, especially near the outlets of subsea pipelines running 100s of kilometres. Due to high solubility of acid gases, the corrosivity of some brines may be high even at such low temperature conditions. Recently, it was observed in the lab that the used corrosion inhibitors performed better at higher temperatures compared to seabed temperatures. At times, such conditions impose tough challenges to qualify a corrosion inhibitor. This paper describes the findings of some low temperature corrosion inhibitor performance studies, attempting to explain the possible reasons of low performance and the possible remedies.