Influence of corrosion products on the inhibition effect of pyrimidine derivative for the corrosion of carbon steel under supercritical CO2 conditions

The effect of corrosion products on the inhibition effect of pyrimidine derivative inhibitor (DABTP) for the corrosion of N80 carbon steel in supercritical CO2 oilfield produced water was studied by electrochemical measurements, surface characterization, and theoretical calculations. It is found that DABTP exhibits high inhibition performance for bare carbon steel, while the formation of corrosion products (Fe3C, FeCO3) after pre-corrosion reduces the inhibition effect of DABTP. Theoretical calculations indicate that DABTP preferentially adsorb on FeCO3 film instead of Fe surface, which results in the reduction of inhibition effect of DABTP after FeCO3 film formed on the carbon steel surface.