基于显微CT图像的岩芯孔隙分形特征

Fractal characteristics of core pore based on micro-CT images

采用国内自主开发的高分辨率显微CT设备,对岩芯样本进行图像采集,运用数字图像分析方法获得图像中的岩芯孔隙目标,并以此为基础重建三维模型。然后基于分形理论,分别从二维图像和重建的三维模型角度计算孔隙的分形维数。最后,再采用基于多孔介质的分形模型对岩芯孔隙分形特征进行验证,得出岩芯的二维分形维数和三维分形维数之间的差值均值为1.000 3,最大偏差为0.004,很好地满足多孔介质分形模型中关于二维和三维分形维数的关系。

The micro-CT has been an increasingly important tool in researching core pore structure. In this study, a domes- tically self-developed high-resolution micro-CT equipment is used to capture the CT images of a core sample. Based on the results from digital image analysis of pore core CT images, this paper reconstructs a three-dimensional model of core pore. Then fractal dimension of two-dimension image and three-dimension reconstructed model are calculated based on fractal theory. Finally, the fractal characteristics between the two-dimension image and the three-dimension reconstructed model of the sample are verified by fractal model of porous media. Wherein, the mean difference between the two-dimensional fraetal dimension and the three-dimen- sional fractal dimension is 1. 000 3, and the maximum deviation is 0. 004. The results well satisfy the relations between the two dimension and the three-dimension fractal dimension of the fractal model of porous media.