Microbial Degradation of Film-Forming Inhibitors and Its Possible Effects on Corrosion Inhibition Performance

Abstract

Abstract Organic film-forming inhibitors used in oil and gas production and transport operations could be susceptible to microbial degradation during their use with the consequent loss in efficiency in corrosion inhibition. The performance of one such organic film-forming corrosion formulation to inhibit corrosion of carbon steel was assessed in a simple mineral medium containing 15.0 ppm sodium chloride. The fluid was inoculated with a Pseudomonas fluorescens pure culture or with a mixed culture of sulfate-reducing bacteria. The inhibitor mixture was the sole carbon source in the system. Microbial growth and the corrosion behavior of carbon steel were simultaneously assessed during periods of time ranging between 3 days and 2 months. Linear polarization resistance and corrosion rates were also measured. The degradation products were separated and identified by gas chromatography mass spectrometry (GC-MS). Although a significant microbial growth was confirmed, no reduction in the corrosion inhibition efficacy was found.