RESEARCH On MICROBE ENHANCING OIL RECOVERY And CONTROL MICROBE CORROSION

Six strains Bacillus producing biosurfactant are screened from Changqing oil-field and they are tolerant to heat and salt-tolerant. The research on four strains candida Berkhout isolated from yeasts in our Laboratory indicated they are salt-tolerart. In oil industry, the two kinds of microbe can both enhancing the oil recovery. Experiment showed the best proportion of coculturing them is 1∶4 and the optimum medium is consisted of 0.8% sucrose, 0.8% (NH4)2SO4, 0.11% kcl, 0.11% NaNO3, 0.34% KH2PO4 0.44% K2HPO4, 0.05% MgSO4, 0.05% yeast extract paste, 4% oil, 0.8% mineral elemental solution, the surface tension and viscosity of oil is decreased by 46.5% and 78.8% respectively.Furthermore, the feasibility of Bacillus, yeasts and heterotrophic bacteria compete with SRB to control the Microbe corrosion. The conclusion of coculturing them is that it is not very eviden to control the corrosion and improve the oil, which probably account for the competition among them and the inhibition from H2S. But to some extent, combinating the Microbe corrosion control and Microbe the oil recovery is feasible.