二元驱体系水动力尺寸与储层喉道尺寸匹配关系

Relationship Between Reservoir Throat Size and Hydrodynamic Size for Binary Compound Flooding

针对低渗透油藏二元驱过程中聚合物分子量和浓度选择无依据的问题,首先,采用激光粒度分析仪测试不同条件下二元驱体系水动力学尺寸,明确了二元驱体系水动力学半径随聚合物分子量、聚合物浓度、表面活性剂浓度、基液矿化度的变化规律;然后,通过恒速压汞实验测试不同渗透率人造岩心平均喉道半径,并拟合出了人造岩心渗透率与平均喉道半径经验公式,最后,基于二元驱体系注入性实验结果,结合现场数据计算得到的判定标准,明确当岩心渗透率小于20×10^(-3)μm^(2)时,注入聚合物的分子量应小于300万,质量浓度小于500 mg/L;当岩心渗透率处于20×10^(-3)~40×10^(-3)μm^(2)之间时,注入聚合物的分子量应小于500万;当岩心渗透率处于40×10^(-3)~70×10^(-3)μm^(2)之间时,注入聚合物的分子量应小于1200万,结合基液矿化度和表面活性剂浓度对二元体系水动力尺寸影响规律,可为现场二元体系配方调整提供指导。

Aiming at the problem that there is no basis for selecting the molecular weight and concentration of polymer in the process of adopting the binary composite flooding in low permeability reservoir,the laser particle size analyzer is used to test the hydrodynamic dimensions of the binary compound flooding system under different conditions,and the change law of the hydrodynamic diameter of the binary compound flooding system with the molecular weight of polymer,the concentration of polymer,the concentration of surfactant and the mineralization degree of the base fluid was clarified.The average throat radius of cores with different permeability was tested by constant velocity mercury injection experiment,and the empirical formula of artificial core permeability and average throat radius was fitted.based on the injection test results of the binary flooding system and the judgment criteria calculated by the field data,it was clear that when the core permeability was less than 20×10^(-3)μm^(2),the molecular weight of the injected polymer should be less than 3 million and the concentration was less than 500 mg/L;when the core permeability was between 20×10^(-3)—40×10^(-3)μm^(2),the molecular weight of the injected polymer should be less than 5 million.When the core permeability was between 40×10^(-3)—70×10^(-3)μm^(2),the molecular weight of the injected polymer should be less than 12 million.The influence of the salinity of the binding base solution and the concentration of the surfactant on the hydrodynamic size of the binary system could provide guidance for the adjustment of the on-site binary system formula.