疏松砂岩油藏储层物性时变研究进展及前景展望

Research progress and prospect on time varying of physical properties of unconsolidated sandstone oil reservoirs

油田经过长期开发,受驱替介质冲刷或吸附、滞留等多因素作用,储层渗透率、孔隙结构、润湿性、相对渗透率及原油黏度等物性参数发生明显变化。储层物性时变研究方法主要有以下3种:取心井物性对比方法、物理模拟驱替实验方法、数值模拟方法。取心井物性对比方法受经济成本制约,采样位置、数量及采集时间对研究结论有重要影响;物理模拟驱替实验方法借助岩心驱替、核磁共振和CT扫描仪等仪器,可实时获取驱替过程中储层物性参数(如孔隙度、渗透率、相对渗透率及剩余油饱和度等)的变化规律,但实验条件与实际油藏开发过程的相似性有待进一步提高;数值模拟方法可实现对水驱油田剩余油分布、含水率、产液量及采收率的定量预测,但对聚合物驱油过程研究较少。随着越来越多油田进入“双高-双特高”阶段,需加大对储层时变机理探索力度,构建基于物性时变的剩余油精细表征及模拟技术,以物性时变为基础优化调整油田后期开发策略,为提高采收率奠定基础。

After the long-term development of oilfields,under the effect of multiple factors such as the scouring,adsorption and retention of displacing medium,parameters of physical properties,including reservoir permeability,pore structure,wettability,relative permeability and oil viscosity of the reservoir have been changed significantly.Three methods are mainly used to study the time varying of reservoir physical properties,namely coring well physical property comparison method,physical simulation displacement experimental method and numerical simulation method.Coring well physical property comparison method is restricted by economic cost,and the research results are significantly influenced by sampling location,sample quantity,as well as sampling time.Physical simulation displacement experimental method can obtain the time varying rules of real-time reservoir physical parameters(such as porosity,permeability,relative permeability and remaining oil saturation,et al)during the displacement process with the help of core flooding,NMR and CT techniques;however,the similarity between the experimental conditions and the actual reservoir development process needs to be further improved.Numerical simulation method can achieve quantitative prediction of remaining oil distribution,watercut,liquid production and oil recovery in water drive oilfields,but lacking research on polymer drive process.As more and more oilfields entering the"double high,double ultra-high"stage,it is necessary to explore the time varying mechanism of reservoirs,build fine characterization and simulation techniques for remaining oil based on physical property time varying,and optimize and adjust late-stage development strategies of oilfields on the basis of physical property time varying.in order to lay the foundation for improving oil recovery.