| Earth sciences is undergoing a gradual but massive shift from descriptions of the earth and earth systems, toward process modeling, simulation, and process visualization. This shift is very challenging because the underlying physical and chemical processes are often nonlinear and coupled, and take place in strongly heterogeneous systems. An example is two-phase fluid flow in rocks: a nonlinear, coupled, and time-dependent problem in complex microgeometry. To understand these complex processes, the knowledge of the underlying pore-scale processes is essential. This work focuses on building transport process simulators in realistic pore microstructures.; These pore-scale simulators will be modules of a computational rock physics framework with future acoustic, elastic, electrical and NMR property simulators. This computational environment can significantly complement the physical laboratory, with several distinct advantages: rigorous prediction of physical properties, interrelations among the physical properties, and simulation of dynamic problems with multiple physical responses. This dissertation is initiative for the computational rock physics framework—a quantitative model for coupled, nonlinear, transient and complex behavior of earth systems.; A rigorous pore-scale simulation requires three important traits: reliability, efficiency, and the ability to handle complex microgeometry. We implemented single-phase and two-phase flow simulators using the Lattice-Boltzmann algorithm, since it handles very complex pore geometries without idealization of the pore space. The single-phase flow simulator successfully replicates fluid flow in a digital representation of real sandstone, and predicts permeability very accurately. Furthermore, two applications using the single-phase flow simulator are proposed: a permeability estimation technique from thin sections, and diagenesis modeling with fluid flow. These two applications show the potential applicability of this robust pore-scale simulator to modeling multiple physical responses. The two-phase flow simulator replicates many two-phase flow phenomena, such as Laplace's law, capillary pressure, and snap-off in a pore doublet. It can be used to study a wide range of phenomena, including the effects of wettability, capillary pressure and hysteresis. To overcome long calculation time of fluid flow simulation, parallel single-phase and two-phase flow simulators are also implemented. Customized optimizations for the Lattice-Botlzmann algorithm give very good performance. |
