聚驱后油藏剩余油分布数值模拟

通常聚合物驱的最终采收率在50%左右,聚合物驱后剩余油具有相当的开采潜力。以大庆长垣北部多段多韵律聚驱主力油藏为例,采用化学驱油藏数值模拟技术,系统研究并总结了典型油藏聚驱后平面及纵向剩余油的分布特征。结果表明,聚驱后油藏剩余油的分布系统可划分为2大成因、3大区域和7个部位。其中:存在受地质因素制约的剩余油,如废弃河道中部、砂体尖灭区、相对孤立的薄差砂体;也有开发因素控制的剩余油,如厚油层顶部剩余油、注采不完善部位、注入井间与生产井附近以及聚驱后高渗层内的残余油。聚合物驱后油藏剩余油主要富集于3大区域内,究其原因则主要源于水驱和后续聚驱波及程度的不同。

Reservoir Residual Oil Distribution Law After Polymer Flooding by Numerical Simulation Method

Normally,oil recovery after polymer flooding is about 50%.Residual oil reserves after polymer flooding own pretty high exploration potential.In this paper,the key multi-section-and-multi-rhythm reservoir in the north of Daqing placanticline is selected at first.Then,the horizontal and vertical residual oil distribution laws after polymer flooding of the typical reservoir have been studied by using reservoir numerical simulation technique for chemical flooding.The research results indicate that the distribution system of reservoir residual oil after polymer flooding can be divided into two causes,three areas and seven locations.Among them,there has one type of residual oil restricted by geologic factors,such as abandoned channel center,sand body pinchout,relatively-isolated,thin and poor sand body.Moreover,another type of residual oil controlled by development factors also exists,such as those on the top of thick oil layers,in the imperfect injection-production parts,middle of injection wells,neighborhood of production wells and high permeability layers after polymer flooding.Meanwhile,reservoir residual oil after polymer flooding can be in three enrichment areas according to the sweep degree diversity during water flooding and following polymer flooding.