Anaerobic microbial communities and their potential for bioenergy production in heavily biodegraded petroleum reservoirs

Heavy oil constitutes the largest fraction of the global oil inventory, representing a resource size of 5.6 trillion barrels. Balancing environmental consequences with economic and energetic needs means that strategies may be necessary to reduce the carbon footprint of heavy oil production. The biogenic conversion of oil to methane has been considered for years, yet no research has been done on the potential of heavily degraded oil, such as Athabasca oil sands, to for biogenic methane production. Here we have investigated this potential with unique long-term incubation experiments (>3000 days) of oil sands and formation water with no external carbon source and no external microbial community added. The results of this work set a benchmark of at the high-end of the degraded oil scale, analyses potential roles of native microorganisms and limitations for biogenic methane production from oil sands.