Pore network modeling

        Variably-saturated flow and multi-component reactive adsorptive transport

PoreFlow is a pore-network model capable of simulating multi-component reactive and adsorptive transport under saturated and variably saturated flow conditions. It provides a powerful tool for upscaling flow and transport in porous media and can be instrumental to gaining a better understanding of how different pore scale physical and chemical processes manifest themselves at larger (continuum) scales (e.g., core scale or lab scale).

The pore space is represented by pore bodies and pore throats utilizing a Multi-Directional Pore-Network (MDPN) generator. MDPN allows for a distribution of coordination numbers ranging between one and 26 with user-defined directional connectivities for anisotropic pore networks. This topological property, together with geometrical distributions of pore sizes, allows us to mimic the microstructure of real porous media.

PoreFlow includes a variety of modules, such as: pore network generator, drainage simulation, calculation of pressure and velocity distributions, and modeling of reactive solute transport accounting for advection and diffusion. The reactions can occur within the liquid phase, as well as between the liquid and solid phases which may result in an evolution of porosity and permeability.

Several complex formulations have been used for more accurate modeling of transport problems in the presence of a non-wetting phase. This is done, for example, by refining the discretization within drained pores. An implicit numerical scheme was used to solve the governing mass balance equations together with an efficient substitution method to considerably minimize computational time.

Several simulations were conducted under saturated and variably saturated conditions to demonstrate the model applicability in hydrogeology problems and petroleum fields. Modeling results can provide quantitative pore scale information on distribution of fluid phases, pore velocities, chemical components and rates as well as upscaled properties such as average phase saturations, permeability (and its change with porosity evolution), interfacial area, upscaled reaction rates, solute dispersivity, and effective diffusion.