| The study of multiphase flow in porous media is of major interest in oil recovery and contaminant remediation in aquifiers. Porous media are modeled as networks of pores and throats (channels). These network flow models depend on a number of parameters supplied by experiments. Interpretation of experimental measurements of a porous medium property often rely heavily on idealized models and equations. In contrast, the development of robust techniques for analysis of X-ray microtomography images can provide direct quantification of geometric parameters for the pore space and fluids resident therein. Such results then serve either as input to network models via parameter estimation or for model verification.; In moderately high porosity (40% to 50%) samples, successful throat finding and pore partitioning has proved particularly challenging. We present improved throat finding methods and introduce a robust pore partitioning scheme. We present results on pore characterization in Berea sandstone and polyethylene cores in the form of parameter distributions required as input to network models. The parameters include volume, surface area, shape factor, principal direction diameters and permeability for both pores and throats. Lattice Boltzmann computations of absolute permeabilities for individual pores/throats are based on exact (to the resolution of the image) configurations and can replace current permeability estimates produced from analytic models based upon geometrically simplified shapes.; In polyethylene core experiments, fluid displacement patterns were obtained both after fixed volumetric injections of invading fluid, and after steady state conditions were reached at fixed fractional flow injection. We concentrate our fluid analysis on overall fluid phase connectivity, interphase contact area, as well as saturation distribution in pores of different sizes. We also report on the ability to differentiate three fluid phases (oil, water, air) in the pore space.; In extensive studies of the Berea core it was observed that introducing water-based gels in the displacement process reduces permeability to water more than to oil. We focus our fluid analysis capability on the effects gelation has on residual fluid and we provide supporting evidence for the involvement of gel compaction (dehydration) and oil trapping, while discounting gel blockage in throats, as mechanisms contributing to this effect. |
