The 3D clay pore structure is reconstructed using a process-based approach with related parameters informed by BIB-SEM images of a shale sample. The detailed reconstruction workflow can be found in the reference below and here we only present a brief introduction.
Christopher J. Landry, Maša Prodanović, Rob Reed, Peter Eichhubl, and Kishore Mohanty, (2017), "Estimating Mudrock Oil-Water Relative Permeability Curves Using Digital Rock Physics," SEG Global Meeting Abstracts : 2711-2731.
https://doi.org/10.15530/urtec-2017-2691701
First the shale core sample is prepared for thin section analysis with a field of view of approximately 1.5 in, which is used for targeting regions of interest. Then the core plug is subsampled with guidance from thin-section imaging and prepared for high-resolution SEM imaging by BIB milling. Large-area high-resolution SEM mosaics are acquired, stitched, segmented, and used to measure the pore size and shape characteristics. Two dominant pore systems (OM and clay pores) are analyzed separately. Here we focus on clay pore system where in-situ water is most likely to reside. A process-based reconstruction process is conducted by placing ellipsoids of different length (assuming constant aspect ratio) and tilt measured by image analysis. The ellipsoids are simplified representations of clay plates. The insertion of ellipsoids is terminated when the desired porosity measured from BIB-SEM images is reached, and the 2D pore statistics of the 3D reconstruction is compared to SEM observations for validation purpose.
