Challenges and Opportunities in Petroleum Microbiology
Reservoir souring is a well-known microbiological issue in the oil and gas sector; the production of hydrogen sufide (H2S) by sulfate-reducing bacteria (SRB) creates a safety hazard, lowers the quality of the produced gas and oil, and contributes to microbially induced corrosion (MIC). Whereas achieving microbial control in oil field settings to combat souring and corrosion can be achieved by biocide application, microbial ecology and an appreciation of reservoir habitats and microbiomes offers other routes for souring mitigation and management. Injecting nitrate has the potential to control souring by stimulating nitrate-reducing bacteria that can compete for substrates with SRB and, in some cases, oxidize H2S directly. However, nitrate may have unintended consequences by exacerbating corrosion via intermediate S and N metabolites.
Our group is investigating these questions in both conventional and unconventional (shale) reservoirs that typically harbour extremophiles (thermophiles; halophiles). Survival of extremophiles may be aided by spore formation, enabling certain problematic Clostridia to survive through the various stages of oil field water use and recycling.
The Geomicrobiology Group’s research on petroleum microbiology is and has been funded by NSERC and Chevron.