Table of Contents
ABSTRACT
This chapter presents an overview of the microbiology influenced corrosion caused by sulfate-reducing bacteria (SRB) and how to determine its effects on metal structures in oil and gas industries. Sulfate reducing bacteria are a group of specialized microorganisms that occur in aqueous environments in the absence of oxygen. The nutrition for SRB depends on the simple organic acids as carbon source in presence of molecular hydrogen (H2) from decomposing natural organic matter. The hydrogen sulfide, H2S is produced as metabolites from the process of metabolism as a result of reduction of sulfate to sulfide.
The formed H2S is the main factor in the dangerous effects caused by SRB as well as it contaminates gas and stored oil, precipitates ferrous sulfide that plugs injection wells and promotes corrosion. The corrosion of iron and steel will occur exactly in the absence of oxygen (anaerobic corrosion). The mechanism by which SRB are involved in corrosion is concerned with their ability to depolarize iron surfaces by consumption of cathodically formed hydrogen and it is briefly explained. The measure of growth of the SRB is carried out by serial dilution method and the most probable number was used to detect the bacterial counts presented.
On the basis of measured growth characteristics of the SRB, possibilities for controlling their activity are discussed. Possibilities for controlling their activity are discussed. The control of SRB by using biocides is well discussed and briefly done by using alternatively injection of oxidized and none oxidized biocides.
