Corrosion product compositions of Methanogen-induced microbiologically influenced corrosion (Mi-MIC) are impact by environmental conditions

Microbiologically influenced corrosion (MIC) is a well-known phenomenon in the reservoir and oil industry. However, the role of methanogen (Mi-MIC) are often neglected (< 0.065 mm/yr) since siderite, the only known corrosion product, is not electrically conductive. In previous studies static incubations were used for the determination of the corrosion rates. Utilizing these approaches for this purpose is resulting in insufficient information on the corrosion rate and corrosion product. A unique approach, a multiport flow column, was used to simulate the natural environment. With the multiport flow column, we could gain much higher corrosions rates (0.72 mm/yr). Corrosion products were further analysed with a combination of ToF-SIMS, SEM-EDS and SEM-FIB, indicating the dominant corrosion products contained phosphorus, oxygen, magnesium, calcium and iron. The corrosion layer also lacked carbon-related species, indicating siderite is not the sole corrosion product, which was previously reported. Methanogens may have influenced the nucleation process of siderite, converting bicarbonate into carbon dioxide for methanogenesis, resulting in increased localized corrosion and reduced siderite formation. To verify and further our understanding of Mi-MIC, we are currently studying the influence of pH on Mi-MIC. Our observations can help to optimize mitigation strategies in the reservoir and oil industry as well as to understand the corrosion mechanism behind Mi-MIC.