Flow Simulation with the Lattice Boltzmann Method in 3D Porous Structures of Pyrolyzed Oil Shale Cores Using Multiscale X-Ray CT Imaging

The pore structure and connectivity of pore space are important features which determine fluid flow in oil shale during pyrolysis in the production of shale oil. Using a combination of Micro and Nano X-ray computed tomography (CT) and 3D image analysis software, 3D pore networks, kerogen phase, crack structure and flow channels of Mahogany oil shale core samples were characterized before and after pyrolysis at a voxel resolution from several microns to 60 nm. The pore and crack network structure deduced from the images was used in Lattice Boltzmann simulations to calculate the permeability in the pore space. The permeabilities of the pyrolyzed samples of the silicate-rich zone were on the order of milli-Darcies, while the permeabilities of the kerogen-rich zone after pyrolysis were very anisotropic and about four orders of magnitude higher