On-Site Trial Study of Denitrification to Suppress Sulfate-Reducing Bacteria (SRB) in Polymer Flooding Wastewater

Sulfate-reducing bacteria (SRB) is a common group of harmful bacteria in oilfield production, capable of reducing oxidized sulfur compounds such as sulfates (SO42-, SO32-) to sulfide ions using various organic materials including petroleum and natural gas as carbon sources. This metabolic process by SRB poses significant hazards to oilfield operations: SRB-induced corrosion by removing hydrogen ions from metal cathodes; safety risks due to the production of hydrogen sulfide; and a decrease in polymer viscosity in polymer flooding oilfields, affecting the effectiveness of polymer flooding. The current effective method to mitigate the hazards of SRB is biological suppression through the introduction or activation of nitrate-reducing bacteria (NRB), leveraging inter-species competition. This paper conducted an on-site trial at a polymer flooding station in Shengli Oilfield, achieving satisfactory results.