Evaluation of the characterization and oil displacement ability of a new type of temperature-and salt-tolerant microbial polysaccharide
To address the problem of increased planar and vertical heterogeneity during water flooding in high-temperature and high-salinity reservoirs,which leads to water breakthrough and low water injection utilization,the existing polymer system cannot fully meet development needs.In this study,a new type of temperature-and salt-tolerant microbial polysaccharide was obtained via fermentation.The structural characteristics of microbial polysaccharides were analyzed and clarified using different methods.The microbial polysaccharide maintained high viscoelasticity after being stored at high temperature of 90 ℃ and high salt concentration of 50 000 mg/L for 60 days,demonstrating its suitability for high temperature and high salinity reservoirs.Through the displacement experiments by cemented cores with different permeabilities,it is confirmed that the polysaccharide can establish the displacement pressure difference at different sites of the core with permeability＞300 × 10-3μm2,migrate to the deep part of the cores and expand the sweep range.The physical displacement experiments improved the displacement efficiency by 13.2％on the basis of blank experiment,with a maximum decrease of 18.4％in water cut.In conclusion,the microbial polysaccharides developed in this study provide a feasible technical solution for improving oil recovery from high-temperature,high-salinity reservoirs.
high temperature and high salinity oil reservoirmicrobial polysaccharideviscoelasticitymigrationdisplacement efficiency
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