Determination of Specific Surface of Rock Grains by 2D Imaging

Abstract

Specific surface is an important parameter for predicting permeability of porous rocks. Many digital methods have been invented to extract the rock properties via imaging such as Micro-CT. With utilizing 3D volume data, this helps in precise investigation; however, it is neither economically efficient nor can be applied for different situations. In this study, a new approach is developed to estimate rock specific surface using 2D thin section images with micron resolution. One specific conclusion of this study is that there is specific ratio between the specific perimeter of 2D images and the specific surface in the 3D real rock structure. To further investigate this ratio several 3D blocks of rock volume data have been virtually cut in every possible angle and the value of specific perimeter calculated for each obtained 2D thin section. Finally, the predicted value of specific surface for 6 rock types is compared with the real values calculated from the original 3D data. Result indicates acceptable precision of this approach for sandstone rocks whereas not applicable for carbonate rocks.