MECHANISTIC AND KINETIC STUDIES OF MICROBIOLOGICALLY INFLUENCED CORROSION(MIC) IN THE PRESENCE OF DOMINANT SULPHATE REDUCING BACTERIA (SRB) METABOLIC SPECIES

Microbiologically influenced corrosion (MIC) is a serious problem in the oil andgas industry. The most common microorganism responsible for MIC is sulphate reducing bacteria (SRB) which produces detrimental sulphide ions into the environment. Therefore, many studies have been conducted to study the effect of sulphide ions on the corrosion rate of mild steel using inorganic solution chemistry but ignored the possible effects of other SRB metabolic species which are produced along with sulphide such as sulphite, lactate, acetate, pyruvate and thiosulphate. The exclusion of other metabolic species implies some deficiency of the current understanding of MIC problem. Thus, the objective of this work is to elucidate the mechanistic and kinetic of MIC with the presence of dominant SRB metabolic species by which a better MIC prediction could be formulated. The work was conducted in simulated solution containing dominant SRB metabolic species of sulphide, sulphite, lactate, acetate, pyruvate and thiosulphate. Three electrochemical measurement methods were used in this work i.e. linear polarization resistance (LPR) test, Tafel polarization (TP) and electrochemical impedance spectroscopy (EIS)