Two-phase Flow Calculations in Pore Unit-cells Implementing Mixed FEM/Lattice-Boltzmann Simulators

Macroscopic two-phase flow in porous media is, in general, a mixture of connected and disconnected oil flow. The latter is expressed as ganglion dynamics and drop traffic flow. Disconnected flow is central in all modern simulators implementing pore network modeling. The computational effort, associated with the solution of the two-phase flow problem (including the effects of bulk viscosity and interfacial capillary pressure) within conduits of varying or complicated geometry, is a critical factor in deciding on the particular numerical scheme(s) to tackle the problem. In the present work, realistic pore-scale CFD calculations of unit-cell conductances have been performed for various flow configurations using single- and two-phase finite element methods. These calculations have been compared against less intensive computations implementing semi- analytical lubrication approximation methods. Results show that, for the given flow and geometry settings the discrepancy between the CFD and Lubrication approximation predictions is well within an acceptable range.