In order to deeply understand the mechanism of polymer flooding and optimize the parameters of the flooding, the kinetic mathematic model is established for the oil saturation changed with the time in the course of polymer flooding with the help of fractional flow theory. On the bases of the knowledges of the acting mechanism and migration laws between the crude oil and polymer solution, the existence of the crude oil enriched and aggregated process is exposed in theory for the front of polymer solution in the flooded reservoir, finally the oil bank is formed as result of gradual accumulation of the crude oil. According to the flowing properties of the polymer solution in the porous media, the influencing factors on the oil enrichment and aggregation are investigated and researched by the established model: the polymer mass concentration gradients in the front; the relation between the polymer viscosity and mass concentration; the polymer solution elasticity and the water relative permeability reduction caused by the polymer. The study results show that the polymer flooding with higher molecular weight and higher concentration has a big potential to enhance the oil recovery, thus the achievements stated above have provided sci-entific theoretical foundation for the choices of the relative molecular weight and injected mass concentration in the course of polymer flooding.%为了深入认识聚合物驱油机理,优化聚合物驱油参数,利用分流理论建立了聚合物驱油过程中含油饱和度随时间变化的动力学数学模型.基于原油和聚合物溶液作用机理、运移规律的认识,从理论上揭示了油藏中有聚合物驱替液的前缘原油富集聚并过程的存在,随着原油不断的富集聚并,油藏中会形成油墙.根据聚合物溶液在多孔介质中的渗流特性,利用建立的模型研究聚合物驱过程原油富集聚并的影响因素:聚合物溶液前缘的质量浓度梯度、聚合物黏度—质量浓度关系、聚合物溶液弹性和聚合物引起的水相相对渗透率下降.结果表明,高相对分子质量、高质量浓度聚合物驱具有大幅度提高采收率的潜力,为聚合物驱油过程相对分子质量和注入质量浓度的选取提供了科学的理论依据.
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