Internal corrosion failures in oil and water pipeline networks are frequently implicated from microbiologically influenced corrosion (MIC). Corrosive microorganisms can contribute to potential corrosion risks and metal loss, but their presence does not always correlate to MIC occurring. 22 oil and sludge samples were collected from various crude oil pipelines for microbiological and compositional analyses to verify the quality of the internal pipeline and assess the possible microbial contributions to the corrosion products accumulated within those pipelines. Three pipelines were shown to have very high number of corrosive microbes (sulfate-reducing bacteria and methanogens) in the crude oil they transport. Three sludge samples were detected to contain high wt.% of various iron sulfide compounds, Greigite [Fe3S4], Mackinawite [FeS]), and Pyrite [FeS2]. Two Sludge samples comprised more than 85% of elemental sulfur. Some of the assessed pipelines are currently under monthly monitoring program for microbial activities. If high number of corrosive microbes is persistently detected, enhanced corrosion mitigation measures such as biocide treatment may be implemented.
Microbiologically influenced corrosion (MIC) has been an emerging concern in the oil and gas industry. Pipeline networks of different services, such as sour crude, sweet crude, water, and gas are subjected to various corrosion types, including MIC from microbial activities present within these systems. Such microbial activities can hinder the pipeline integrity and lead to metal deterioration [1]. MIC failures attribute to 20-40% of serious corrosion cases, in addition to the majority of internal pipeline leaks being caused by MIC microorganism's localized corrosion [2].
Moreover, various microorganisms prosper in oil, water, and gas systems due to the presence of nutritious elements within those systems [1]. Thriving microorganisms require carbon source, water, and an electron donor and acceptor, all of which can be present in those systems [1,2].
Representatives of the microorganism types present in pipeline systems associated with MIC are Sulfate-Reducing Bacteria (SRB), Iron-Oxidizing Bacteria (IOB), and Methanogenic Archaea (MET) [3].
