Unconventional rocks such as tight sandstone and shale usually develop multiscale complex pore structures, with dimensions ranging\nfrom nanometers to millimeters, and the full range can be difficult to characterize for natural samples. In this paper, we developed a\nnew hybrid digital rock construction approach to mimic the pore space of tight sandstone by combining X-ray CT scanning and\nmultiple-point geostatistics algorithm (MPGA). First, a three-dimensional macropore digital rock describing the macroscopic pore\nstructure of tight sandstone was constructed by micro-CTscanning. Then, high-resolution scanning electron microscopy (SEM) was\nperformed on the tight sandstone sample, and the three-dimensional micropore digital rock was reconstructed by MPGA. Finally, the\nmacropore digital rock and the micropore digital rock were superimposed into the full-pore digital rock. In addition, the nuclear\nmagnetic resonance (NMR) response of digital rocks is simulated using a random walk method, and seepage simulation was\nperformed by the lattice Boltzmann method (LBM). The results show that the full-pore digital rock has the same anisotropy and good\nconnectivity as the actual rock. The porosity, NMR response, and permeability are in good agreement with the experimental values.
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