Imaging, pore network generation and transport prediction

This paper describes the imaging and analysis of rock samples with the eventual aim of predicting single and multiphase flow and transport properties. Micro scale X- ray tomography allows rocks to be imaged in three dimensions with a resolution of a few microns. The experimental apparatuses of industrial micro-CT system and synchrotron beamline generated X-ray tomography are described and issues associated with image processing to obtain a binary representation of void space and solid are addressed. A number of pore network models to simulate two- and three-phase flow have been developed that can predict relative permeability once the pore geometry and wettability are known. We adopt a modified maximal ball algorithm to obtain the morphological model of porous media from a three-dimensional image of the pore space. The pore and throat size distributions are computed as well as the coordination number for each pore. Consequently, by using a series of rules to determine fluid displacements in pores and throats, multiphase flow can be simulated and predictions made. To verify the results from the maximal ball algorithm predictions from the extracted network are compared with experimental measurements of absolute and relative permeability on the core and lattice Boltzmann simulation of single-phase flow on the 3D pore-space image. The pore and throat size distributions are used to tune the Berea network for the predictions.