| The microbial combination flooding is a method of Microbial Enhanced Oil Recovery,which use the composite system produced by biopolymers and bio-surfactants to drive oil.Through the fermental cultivation of biopolymer-producing bacteria and biosurfactant-producing bacteria above the ground, biopolymers and bio-surfactants will be obtained, andthen their fermentation broth will be injected into oil reservoir to enhance oil recovery. Withthe combined synergistic effects of biopolymers and bio-surfactants, the biologicalcombination flooding not only has the characteristics of microbial flooding, but also has theadvantages of compound flooding. Therefore, it has much more advantages than the ordinarymicrobial enhanced recovery, and is safer and cleaner than the chemical combinationflooding.In this paper, five biosurfactant-producing bacteria and one biopolymer-producingbacterium were separated and purified from the Daqing oil factory produced water. And weevaluated the reservoir adaptabilities of these strains and selected their optimal fermentationconditions. According to the experimental results, two strains of biosurfactant-producingbacteria and one strain of biopolymer-producing bacteria were screened, which wereendogenous bacteria B2and B4and exogenous bacterium DJ. Then, studied the ability ofadapting to the reservoir, the B2/DJ compound system and the B4/DJ compound system havetheir respective application conditions. It was found that the B2/DJ compound system wassuperior to the B4/DJ compound system. The adaptation interval of B2/DJ were thattemperature was in40℃~90℃, the concentration of NaCl was in0~200g/L, pH was in5~10and shear velocity was in0~10000r/min. And it could be stored at room temperature for30days. Finally, with the oil displacement experiment in laboratory, evaluated the oilrecovery efficiency of B2/DJ compound system, it drew a conclusion that the oil recoverywas improved obviously after water flooding. The oil recovery was enhanced13%. |
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