Multiphase Flow Simulations Using a New Kind of Pore Network

Based on synthetic porous media and on three-dimensional images of real porous media we construct pore networks, the nodes of which represent pore bodies and the edges of which describe connections of pore bodies through pore throats. The novelty of our approach is that the geometries of the pore bodies and the pore throats are given explicitly. In particular, the pore bodies [pore throats] take the form of three-dimensional [two-dimensional] cellular complexes such that (1) the pore throats separate the pore bodies and (2) the union of all pore bodies and pore throats yields a cellular complex that approximates the three-dimensional pore space. In contrast to an earlier approach by the authors, the throats now extend into the narrowing ends of the pore channel cross sections and thus allow better estimates of critical pressures for drainage through the pore throats. Likewise, the pore bodies now allow better estimates of critical pressures for imbibition through the pore bodies. We will simulate both drainage and imbibition, take entrapment into account, and compare the capillary pressure-saturation curves from the simulations with data obtained from real experiments.