Effect of SRB, CO_2, Crude Oil and Chemical Treatment on the Corrosivity of Synthetic Produced Water

摘要

The combined effect of sulphate-reducing bacteria (SRB), CO_2 and crude oil on the corrosion of carbon steel in produced water were investigated using a rotating cage. During the experiment, pH, planktonic SRB, and concentrations of sulphide, sulphate, iron, calcium and magnesium ions were monitored. After the experiment, the sessile SRB were enumerated by serial dilution and optical microscopy, scanning electron microscopy, mass loss and laser profilometry were used to identify corrosion products, bacterial cell and corrosion rate. Both mass loss and localized pitting corrosion were two and three times higher in solutions containing 10 % SRB and 10 % CO_2 respectively compared to solutions containing either 10% CO_2 or 10% SRB alone. The crude oil evaluated has a 50% emulsion inversion point, a mixed-wet wettability and inhibitive characteristic because there was a 26% reduction in mass loss. A commercial package of treatment based on quaternary ammonium salts with filmic corrosion inhibitors, glutaraldehyde with quaternary ammonium salts as a biocide and polyepoxysuccinic acid as a scale inhibitor decreased corrosion rate by 96%, controlled the SRB lower than 102 cells/cm2 and reduce the risk of scales.