Use of electrochemical impedance spectroscopy for study of CO2corrosion prevention by batch treatment inhibitor films

Abstract Electrochemical impedance spectroscopy (EIS) was used to study and evaluate commercial batch treatment inhibitors which are used for protecting oil wells, gas wells, and pipelines from CO2 corrosion, focusing on the evaluation of inhibitor film persistency. It was found that theformation and deterioration of batch treatment inhibitor films were accompanied by typical impedance spectral changes. During the formation of inhibitor films, electrode impedance showed a rapid increase and the Bode phase angle plots also showed a sudden change. Thus, the formation of inhibitor film was a very fast process. During the deterioration of inhibitor films, electrode impedance showed a gradual decrease and the Bode phase angle plots showed changes which characterised the three stages of the inhibitor film deterioration process. The relationships between EIS and corrosion rate are discussed, including comparisons with weight loss measurements. Based on the experimental findings in the present work, a method is s...