不同类型储层物性关系研究

Research on the Relationship Between Different Types of Reservoirs Physical Properties

基于大庆油田179块岩芯实验数据,对储层渗透率分类,探讨了不同分类条件下渗透率、孔隙度、中值半径、束缚水饱和度之间的关系,并给出了渗透率与孔隙度的最优拟合关系式,同时结合岩心扫描电镜及实验数据分析了孔隙度、中值半径、束缚水饱和度与渗透率的相关性。结果表明:基于渗透率分类能在一定程度上提高孔隙度与渗透率拟合精度;大于100 mD的岩芯,与渗透率相关性从大到小排列有:中值半径r_(50)、束缚水饱和度S_(wi)、孔隙度φ,其中中值半径是主控因数,其平方值与渗透率有最佳的线性相关性;对于渗透率小于20 mD的岩芯,与渗透率相关性有:束缚水饱和度S_(wi)>孔隙度φ>中值半径r_(50),当渗透率小到一定值时,喉道对流体渗流影响被削弱,而孔隙的影响会增大;对于渗透率在20~100 mD之间的岩芯,束缚水饱和度、中值半径与渗透率相关性最差,拟合孔-渗关系式建议采用幂指数函数。

Based on the experimental data of 179 cores from Daqing oilfield,the permeability of the reservoir was classified,and the relationship between permeability,porosity,median radius,and irreducible water saturation under different classification conditions was discussed,the optimal fitting relationship between permeability and porosity was given,and the correlation between porosity,median radius,irreducible water saturation and permeability was analyzed based on core scanning electron microscope and experimental data.The results showed that the classification based on permeability improved the fitting accuracy of porosity and permeability to a certain extent;for cores with the permeability larger than 100 mD,the correlation with permeability was arranged in descending order:median radius r_(50),irreducible water saturation S_(wi),porosity φ,among them the median radius was the main controlling factor,and its square value had the best linear correlation with permeability;For cores with the permeability less than 20 mD,the order of correlation with permeability from large to small was as follows:irreducible water saturation S_(wi),porosity φ,median radius r_(50).When the permeability was small to a certain value,the effect of throat on fluid seepage was weakened,and the influence of pores increased;For cores with the permeability between 20 mD and 100 mD,irrelevant water saturation and median radius had the worst correlation with the permeability.It was recommended to use a power exponential function to fit the porosity-permeability relationship.