Abstract:The Shengli oilfield has rich remaining reserves after polymer flooding, the existing layer series and well pattern are not well prepared for its subsequent development. In order to further improve oil recovery and increase economic efficiency by subdividing layer series, this paper makes a study on layer adjustment for surfactant-polymer flooding reservoirs after polymer flooding in Gudong west 7 area, by means of numerical reservoir simulation. On the basis of chemical flooding of investment and cost analysis, a set of layer adjustment limit plates proposed to surfactant-polymer flooding reservoirs after polymer flooding has been established with the dynamic economic evaluation methods. Combined with the non-homogeneity composite index of each layer calculated by the entropy weight algorithm and the optimal partitioning scheme determined by the cluster analysis, we screen out the optimal partitioning scheme to meet the requirements. Taking this method to make layer adjustment for surfactant-polymer flooding reservoirs after polymer flooding, the results show that: after layer series adjustment, the recovery efficiency of Gudong west 7 area has increased by 3.45%, and the financial net present value has increased by 1.746 million yuan. The effect of layer adjustment is remarkable.