Abstract: The application of supercritical CO2 flooding technology brings huge safety risks to the storage，transportation in the downstream of the petroleum industry. The law of corrosion inhibition of HHS-08 oil-soluble corrosion inhibitor (HHS-08 corrosion inhibitor) in the environment of supercritical CO2 flooding oilfield water was studied. HHS-08 inhibitor with different concentration was added to the above oilfield water successively，and polarization curves and electrochemical impedance spectroscopy of the corrosion system were tested by CHI604E electrochemical workstation. The adsorption behavior and mechanism of HHS-08 corrosion inhibitor on the Fe（001） plane were investigated by Materials Studio 8.0. The results of macroscopic morphology，corrosion weight loss test，polarization curves and impedance spectroscopy showed that the inhibition rate increased with the increase of HHS-08 inhibitor dosage. The corrosion inhibition efficiency reached a value of more than 80% at the concentration of 80 mg/L，however，the inhibition efficiency increased little when the dosage was increased further. The results of molecular dynamics showed that the HHS-08 inhibitor molecule could stably adsorb the polar head group (imidazole ring) on the Fe (001) plane through its own torsion deformation, while the alkyl carbon chain deviated from the metal surface to form a hydrophobic film, thus achieving good corrosion inhibition.

Key words: corrosion inhibitor, polarization curve, electrochemical impedance spectroscopy, molecular dynamics simulation