基于数字化孔隙模型的聚驱后微观剩余油定量表征

Quantitative characterization of micro residual oil after polymer flooding based on digital pore model

利用岩心压汞试验数据和CT扫描数据,构建波纹管状数字化孔隙模型,考虑聚合物溶液的黏弹性、不可及孔隙体积及吸附滞留特性,模拟不同驱油体系在该孔隙模型中的驱油过程,定量表征不同驱油体系的驱油效果及对不同类型剩余油的作用。结果表明:构建的数字化孔隙模型可以较好地模拟岩心孔隙度和渗透率,其相对偏差均小于5.0%;基于数字化孔隙模型计算的水驱及聚驱后采收率与岩心驱油试验结果的相对偏差分别为1.32%和0.97%;计算的聚驱后各类剩余油饱和度与岩石薄片荧光分析方法得到的结果接近,水驱后及聚驱后剩余油含量较高的为膜状剩余油和簇状剩余油,占剩余油比例超过85%。

On the Basis of the core mercury injection test data and CT core scanning data,a corrugated tubular digital pore model was constructed.Considering the viscoelasticity,inaccessible pore volume,and adsorption retention characteristics of polymer solution,the oil displacement process of different oil displacement fluids in the pore model was simulated.The oil displacement effects and their effects on different types of remaining oil were quantitatively characterized.It is indicated that the constructed digital pore model can effectively simulate core porosity and permeability,and the relative deviations is less than 5.0%.The relative deviations between the recovery efficiency of water flooding and polymer flooding calculated based on the digital pore model and the results of oil displacement experiments in the core are 1.32%and 0.97%respectively.The saturation of various types of residual oil after polymer flooding is similar to the results obtained by the fluorescence analysis method of rock thin sections.After water flooding and polymer flooding,the remaining oil in film form and cluster form is more,accounting for more than 85%of the remaining oil.