Efficacy and Risks of Nitrate Application for the Mitigation of SRB-Induced Corrosion

Abstract

Abstract Sulfate-reducing bacteria (SRB) are one of the most damaging bacteria to the oil and gas industries, and nitrate has been adopted as selective inhibitor of SRB activity to reduce or eliminate the H2S formation and H2S-associated problems. However, the effect of nitrate application on the metal corrosion has been contradictory. In this study, we tested the efficacy of nitrate application alone and nitrate and denitrifying bacteria in combination in mitigation of SRB-induced corrosion under different conditions simulating the field operations. Multiple corrosion-related data were collected with a real-time electrochemical corrosion-monitoring device, and analyzed along with concentrations of SRB, denitrifying bacteria, sulfate, sulfide, nitrate, and nitrite in bacteria culturing and corrosion monitoring units in an attempt to determine the relationship of corrosion rates and metabolic activities of SRB and denitrifying bacteria under various treatment conditions. The results showed that, compared to nitrate application alone, simultaneous application of both nitrate and denitrifying bacteria were more effective in mitigating the SRB-induced corrosion. Effectiveness, benefits, and risks of this approach have been extensively discussed and can be used as guideline for the mitigation of SRB-induced corrosion in gas and oil industry.