Identification of Microorganisms and Their Effects on Corrosion of Carbon Steel Pipelines

The effects of different types of crude oil, water, and temperature on the growth of microbes and the nature of MIC attack were investigated. The microbes and the nature of environment resulting in pipeline steel damage with a well head oil-water mixture were identified. The types of bacteria were characterized by 16S ribosomal RNA gene sequence analysis. The chemical composition of the biofilm that formed on the surface of the carbon pipeline steel specimens was analyzed. Resulting pit depth and morphology were evaluated. The DNA sequences identified specific types of bacteria involved. The microbiological attack was found to be the result of a complimentary interaction of at least two types of bacteria. One type, aerobic bacteria, produces the biofilm and the other, anaerobic bacteria, subsequently produce most of the corrosion damage. In this investigation the higher manganese pipeline steel experienced more severe MIC. This characterization of oil-water environment and microbes behavior offer specific information on the type of microbes involved to be used for future comprehensive analytical tests for establishing the MIC mechanisms.