砂岩多重孔隙结构非均质评价方法

Evaluating method for heterogeneity of multiple porosity sandstone

范玉平 刘慧卿

FAN Yu-ping LIU Hui-qing

中国科学院地质与地球物理研究所, 北京 100029 中国石油大学石油天然气工程学院, 北京 102249 辽河油田兴隆台采油厂, 辽宁 盘锦 124010

建立了砂岩孔隙结构评价的分形结构因子法,25块岩心压汞资料的计算结果表明,这种方法可以定量表示岩石的非均质性。和变异系数相比,分形结构因子与岩石渗透性、孔隙度、阈压、最小非汞饱和度、孔隙大小均值之间具有较好的相关性,说明分形结构因子能够更好地描述岩石孔隙结构的特征。最小湿相(湿相)饱和度与分形结构因子具有很好的线性关系,该关系式同时适用于绝对均质和绝对非均质岩石体。由于压汞过程中的汞对孔隙凸凹的填充,使得孔隙流通通道均匀化,因此和压汞过程相比,退汞过程的分形结构因子普遍较小,即退汞流动通道的均质性增强。

Heterogeneity fractal description of multiple porosity sandstone was established in this paper. Mercury injection experiment was conducted over 25 core samples, which could help to calculate the rock fractal factor and quantitative describe the heterogeneity of multiple porosity sandstone. Compared with coefficient of variation, the fractal factor had better interrelationship with rock permeability, porosity, threshold pressure, minimum wet saturation, and mean pore size. There was a linear relation between fractal factor and minimum wet saturation, which was suitable for both absolute homogeneous and heterogeneous rock. As the filling of mercury in the knaggy pore space made the pore flow channel more uniform, the fractal factor in the mercury ejection process is smaller than that of mercury injection process.

10.3969/j.issn.1000-7393.2006.05.018