Microbiologically Influenced Corrosion (MIC) is a well-documented phenomenon that involves microorganisms and affects multiple industries with untold economic impact. The most well- known microorganisms within the oilfield, by far, are Sulphate-Reducing Bacteria (SRB). It is thought that through SRB respiration, corrosion of metals can occur. An exact figure for MIC responsibility in overall corrosion is currently unknown. However estimates of between 10-50% are not uncommon, when coupled with estimated costs of metal corrosion in developed countries to be between 2-3% of Gross Domestic Product (GDP), suddenly the cost implications of MIC gain significance. The technical and economic implications have gained recognition within the oil and gas industry within the last thirty to forty years and monitoring techniques to detect microorganisms and corrosion have progressed and developed through increased interest in microorganisms commonly found within the oilfield. As with human nature, the ability to predict the future, rather than deal with the consequence is a preferred approach, which is one of the main driver's to pro-active monitoring techniques for detection of microorganisms to help determine the risk of MIC to occur, rather than a reliance on rate of corrosion alone. This approach has led to increased research in to the subject of oilfield microbiology and development of modern molecular techniques, often borrowed from other industries such as medical microbiology, that have come to the fore recently. However a significant focus on cost saving practices within the oil and gas industry has a significant and direct impact on the type and frequency of monitoring applied (if any).
The objective of this review is to discuss and evaluate the available techniques and review the most common problems associated with microorganisms within the oil and gas industry. To determine effective monitoring practices in a practicable and economically viable manner to ensure monitoring can be carried out effectively, understood and evaluated while implementing control and mitigation strategies with confidence.