Consortia of MIC Bacteria and Archaea causing Pitting Corrosion in Top Side Oil Production Facilities

In the oil industry most monitoring of microbiologically influenced corrosion (MIC) has in the past only been conducted on sulfate-reducing Bacteria (SRB) carried out by cultivation based techniques. The cultivation based techniques grossly underestimate the actual population sizes by several orders of magnitude since the majority of SRB are not readily viable in culture.
In this paper it is demonstrated that quantitative Polymerase Chain Reaction (qPCR) is yielding improved information about Troublesome Microbes (TM) involved in MIC. The qPCR technique is based on an enzymatic reaction that exponentially copies a specific gene, i.e. the gene for sulfate reduction. qPCR protocols were developed for TM such as sulfate-reducing prokaryotes and methanogens and applied on a piece of corroded piping from the water outlet of a separator from the Halfdan oil field.
The results showed that not only SRB were involved in the observed MIC. High numbers of sulfate-reducing Archaea (SRA) and methanogens were also measured. Furthermore, the methanogens were particular abundant close to the metal/scale interface. The data indicate that the measured TM speed up the corrosion process by efficiently consuming hydrogen during dissolution of iron. Based on the results, the MIC mechanisms involving SRP and methanogens are discussed.