Evaluation of Corrosion Inhibitors for CO2 Corrosion Using Electrochemical and Non- Electrochemical Techniques

Abstract Corrosion control of carbon steel in oil and gas production with the application of chemicals is widely used due to simplicity of application, availability and economic reasons. The successful corrosion control programs require cost effective corrosion inhibitors that retard the corrosion reactions providing protection. The corrosion inhibitors that are designed to mitigate CO2 corrosion are evaluated using electrochemical and non-electrochemical techniques in this study. These techniques included electrochemical impedance spectroscopy (EIS), polarization resistance, Tafel extrapolation and traditional mass loss measurements. Several corrosion inhibitors with different chemical and physical properties are selected for this study. These chemicals with different characteristics are designed either for batch or continuous treatment in the field. The various electrochemical techniques utilized for the evaluation of the selected corrosion inhibitors provided very consistent results. Furthermore, the EIS technique provided additional information with regards to the protective nature of the inhibitor film that was not attainable from other techniques. The corrosion rates measured for the chemicals based on mass loss data were higher compared to the electrochemical results. However, the ranking of the chemicals with regard to the corrosion protection provided were similar based on each of the selected measurement techniques.