Physical simulation experiment of oil displacement by bacillus subtilis for enhanced oil recovery

Based on the limitation of conventional oil mining technology and the low oil recovery, in this study, with the method of single factor, the fermentation conditions of a strain of bacillus subtilis isolated from contamination soil was optimized, and microbial enhanced oil recovery experiment was carried on.Glucose was determined as the sole carbon source by optimized condition experiment, and the optimum medium formula was(g/L):C₆H₁₂O₆, 30.0;NH₄NO₃, 1.0;KH₂PO₄, 4.1;Na₂HPO₄·12H₂O, 14.3;MgSO₄, 0.096;CaCl₂, 0.000 8;FeSO₄, 0.001 1;C₁₀H₁₆N₂Na₂O₈, 0.0015.It was found that the surface tension of culture medium decreased from 65 mN/m to 25 mN/m.The physical simulation of oil displacement with microbial degradation indicated that the emulsification appeared during the treatment and biodegradation of crude oil resulted in decrease of heavy component in crude oil.In the oil displacement experiments, separately injected fermented liquid and injected microbes first then injected inorganic medium, the oil recovery enhanced of 26.1% and 31.4% respectively.Bacillus subtilis has good prospect in promoting the displacement of residual oil in reservoir.