Characteristics and mechanism of corrosion film formation on antisulphur steels in CO2/H2S environments.

<title/> The present work investigated the characteristics and mechanism of corrosion product films and the corrosion rates of standard and microalloyed 'antisulphur' steels in H₂S/CO₂ containing oilfield environments at various temperatures. The resistance of antisulphur steels to CO₂/H₂S corrosion was highlighted to provide information for material selection in sour oilfields. The corrosion rates were calculated by weight loss carried out in a high temperature and high pressure autoclave. Meanwhile, the surface morphologies of corrosion product films were studied using scanning electron microscopy with energy dispersive spectrometry. The results indicated that the corrosion product films became more protective, and the corrosion rates of chromium containing antisulphur steels substantially decreased, with increasing temperature. H₂S corrosion dominated the corrosion process under the test conditions. In addition, antisulphur steels P110S and N80SS were found to be superior to common steel P110 in CO₂/H₂S corrosion environments especially at temperatures below 120°C. A model for corrosion product film formation and damage was produced. [ABSTRACT FROM AUTHOR]