Microbial enhanced oil recovery, wettability alteration and interfacial tension reduction by an efficient microbial consortium, ERCPPI-2

Potential of a new bacterial consortium of Enterobacter cloacae and Pseudomonas sp. (ERCPPI-2) which was isolated from Iranian heavy crude oil-contaminated soil has been investigated formicrobial enhanced oil recovery. The obtained results showed that IFT reduction and wettabilityalteration were the main mechanisms for more oil recovery from water-flooded cores. It was also found that at simulated reservoir conditions, the consortium produces a stable biosurfactant mixture with excessive oil spreading and emulsification properties caused substantial oil/water IFTreduction. The experimental data from the designed core holder flooding system demonstrated that in situ bacterial growth altered the wettability of the cores towards more water-wet conditions while the cell-free biosurfactant injection reversed it into more oil-wet conditions. I at simulatedreservoir conditions demonstrated that the oi l recovery efficiency due to cell-free biosurfactant solution injection was 27.2% and bacterium injection was able to reduce residual oil saturation below 3% at optimum conditions in spite of the amount of the residual oil saturation at thebeginning of the microbial process. At more severe conditions of a salinity of 5% (w/v) and temperature. of 60 °C the oil recovery efficiency in core holder flooding system were 24.1 and 39.1%, respectively

کلیدواژه ها:

Enterobacter cloacae ، Pseudomonas sp. ، Microbial enhanced oil recovery ، Biosurfactant ، Wettability alteration ، Extreme conditions