Bacillus mojavensis JF-2 produces a lipopeptide biosurfactant that lowers the interfacial tension between oil and water to values 0.01 mN/m. This organism grows in the absence of air and at elevated temperatures and salinities. These are the environmental conditions found in many domestic oil reservoirs. For these reasons, we chose this organism for our studies. Core displacement experiments at elevated pressure showed that about 23% of the residual oil remaining in Berea sandstone cores was recovered. Oil recovery was highly correlated to the amount of biosurfactant produced. In sand-packed columns, substantial amounts of residual oil (up to 43%) were recovered when about 20 g/l of the biosurfactant was used in conjunction with a mobility control agent. A microbially enhanced oil recovery simulator was used to relate oil recovery to biosurfactant concentration. From the model and our data, we found that the minimum biosurfactant concentration needed to recovery substantial amounts of residual oil was about 1 mg/l. At this concentration, about 12% of the residual oil is recovered. With this information and the yield values for the amount of biosurfactant produced from glucose determined from experimental analyses, we estimated that residual oil could be recovered at a cost of about 0.40 to 3.90 dollars per barrel, depending on the size of the amount of nutrients injected in the oil reservoir.
PDF
download
878987797
028-85220240
