碳酸盐岩双孔隙数字岩心结构特征分析

基于扫描电子显微镜(SEM),分别获取用来描述碳酸盐岩大孔隙和微孔隙特征的低分辨率岩心薄片和高分辨率岩心薄片,利用马尔可夫链蒙特卡洛方法构建相应的大孔隙数字岩心和微孔隙数字岩心,并通过叠加法构建出同时描述大孔隙和微孔隙性质的碳酸盐岩双孔隙数字岩心,最后对数字岩心的孔隙结构特征进行分析评价。结果表明:马尔可夫链蒙特卡洛法能够基于真实岩心薄片快速构建出三维数字岩心;叠加法构建的碳酸盐岩双孔隙数字岩心的孔隙连通体积比明显提高,微孔隙的叠加对提高整个碳酸盐岩双孔隙数字岩心的连通性有着重要影响;碳酸盐岩双孔隙数字岩心孔隙尺寸分布大体上遵从双峰分布,能够同时描述大孔隙和微孔隙特征。

Structure characteristics analysis of carbonate dual pore digital rock

Based on scanning-electron microscopy, the lower resolution images were collected to show macro pore properties while the high resolution images were collected to show micro pore properties, and Markov chain Monte Carlo (MCMC) method was used to construct the corresponding macro pore and micro pore digital rock respectively. Then superposition method was used to construct carbonate dual pore digital rock. Finally, pore structures of digital rocks were compared. The results show that MCMC method could reconstruct the 3D digital rock quickly. The carbonate dual pore digital rock constructed by superposition method has a higher percolating volume fraction, which shows that micro pore has an important influence on the total connectivity. The carbonate digital rock constructed by superposition method has a bimodal pore size distribution which could describe the macro pore and micro pore characteristics simultaneously.