Highlights of 10 Years of Research in Petroleum Microbiology

Our research in petroleum microbiology is focused on (i) sulfur cycle management, (ii) corrosion control and (iii) improved production. In (i) we found that the effectiveness of nitrate injections is decreased by formation of zones of nitrate- and sulfate-reducing bacteria along the flow path and increased by partial reduction of nitrate to nitrite (an SRB inhibitor) at high temperature or salinity. Limiting sulfate dispersal is also a good strategy to contain souring. In (ii) we introduced carbon-steel ball-bearings as corrosion probes to show that overdosing of corrosion-preventing chemicals can have the opposite effect and that surface-active biocides decreased corrosion more than biocides with the best kill. In (iii) we found that increasing toluene in heavy oil followed by injection of nitrate is a promising MEOR strategy and that microbial communities in Alberta oil sands, which harboured thermophiles and aerobic fungi, have potential for developing biotechnologies aimed at decreasing bitumen viscosity.