Analysis of hydraulic permeability in porous media: from high resolution X-raytomography to direct numerical simulation.

The development and application of a strategy are presented, for estimating the full tensor of hydraulic permeability of porous media, without any a priori assumption on the principal directions. A comprehensive description of the X-ray tomographic and image analysis techniques is drawn for the quantitative morphological characterization of the pore space. Pore-scale Direct Numerical Simulation is used to compute the velocity and pressure fields in the digital pore space, reconstructed from high-resolution X-ray tomography. A commercial Finite Volume fluid dynamic solver is used, which operates on voxel-based computational meshes. The proposed methodology is validated by reproducing literature results on monodisperse periodic arrays of spheres. The hydraulic permeability of real-life porous media, characterized by highly complex morphology, is compared with laboratory experimental measurements.