储层岩石微观结构性质的分析方法

Analysis methods for reservoir rock's microstructure

介绍了用以分析储层岩石微观结构性质的若干函数,以模拟退火算法建立的数字岩心为基础,详细讨论了各个函数的应用方法,并用这些方法进行了实例计算。研究表明,连通孔隙体积比能够准确描述岩心中孔隙的整体连通性;孔隙尺寸分布函数可以定量表征岩心孔隙的分布;局部孔隙度分布函数不但可以对岩心中孔隙、岩石骨架的最大发育规模进行定量评价,而且能够对岩心均质性进行定性分析;测量单元标准差分布曲线可以为岩心均质性分析时测量单元边长的合理选取提供重要依据;借助局部渗流概率函数能够对岩心的连通性能及是否为各向同性作出合理的定性判断。格子Boltzmann方法计算数字岩心渗透率简便易行、结果准确,可以作为评价数字岩心可靠性的重要标准。

Several functions for analyzing reservoir rock＇s microstructure were introduced, whose application methods were discussed in detail based on the digital core constructed by simulated annealing algorithm. The results show that the total connectivity of the rock pore can be precisely depicted by connecting volume fraction. Pore-size distribution function gives quantitative characterization of the pore sizes distribution while local porosity distribution function can offer qualitative analysis of the core＇s homogeneity as well as quantitative assess for the size of the largest grain and pore. Reasonable side length of the measurement cell for core＇s homogeneity analysis can be suggested by the variance curve of the local porosity fluctuations, and the local percolation probability function can make good qualitative assess for both the pore＇s connectivity and isotropy. Furthermore, lattice Bohzmann method was introduced to calculate the core＇s permeability and shows to be a reliable standard to judge the core＇s quality for its easy application and correct result.