Microbial enhanced oil recovery in Baolige Oilfield using an indigenous facultative anaerobic strain Luteimonas huabeiensis sp. nov

A facultative strain Luteimonas huabeiensis sp. nov. HB-2 isolated from Baolige Oilfield of China was examined for its growth, biosurfactant production, hydrocarbon degradation and the effects on interfacial properties of oil recovery system. Specifically, the effects on reduction of fluid surface tension and oil viscosity, and on increase in emulsification activity for crude oil were evaluated. This was attributed to the combination of the strain's activities including the production of biosurfactants (cyclic lipopeptides) and the degradation of crude oil. The produced biosurfactants can effectively reduce the interfacial tension of oil-water and viscosity of crude oil. Meanwhile, the long-chain hydrocarbons (C20-C35) of crude oil also can be degraded by bacteria resulting in the increase in shorter chain (C10-C19). These activities demonstrated the suitability of strain HB-2 for application in microbial enhanced oil recovery (MEOR). This was confirmed by a laboratory-based core column flooding evaluation, showing an average increase of 11% in oil recovery, which was followed by an oilfield test involving two water injection wells and eight oil production wells over 16 months, resulting in a remarkable increase in the average single well oil production from 0.48 ton/day (without MEOR) to 1.77 ton/day with the highest reaching 9.5 ton/day by MEOR.