EVALUATION OF OIL-FIELD CORROSION-INHIBITORS IN CO2 CONTAINING MEDIA - A KINETIC-STUDY

Film-forming corrosion inhibitors are extensively used to control CO2 corrosion of steel in oil and gas production plants. The performance o f these inhibitors is connected to the persistence and/or regeneration of the protective film. Their active mechanism in the presence of CO2 is still little understood as far as the kinetics is concerned. In th is paper, some of the factors affecting this mechanism have been studi ed with the aid of polarization curves and electrochemical impedance, using rotating disc and cylinder electrodes. The performance of a comm ercially available film-forming inhibitor used in PETROBRAS, the Brazi lian petroleum company, was evaluated. The results show that the effic iency of the inhibitor depends on its residual concentration and on th e hydrodynamic flow conditions. The impedance diagrams provided inform ation on growth, stability and deterioration of the inhibitor film.