Pore-by-Pore 3D Network Modelling of Multiphase Flow

Multiphase flow through permeable media has important applications in a range of hydrologic systems, such as carbon capture and storage and groundwater flow. Pore network modelling (PNM) has the potential to provide fast predictions of macroscopic multiphase flow properties at, or above, representative elementary volumes. However, while promising predictions have been produced, classical approaches to PNMs may lack essential geometric and physical detail necessary to fully realise their predictive capability. In this work, high resolution volume-of-fluid (VOF) simulations of two-phase flow are performed on small systems and used to further develop the generalised network model (GNM) [Raeini et al, 2018], which exhibits a finer discretisation of pore-space geometry relative to classical networks. It is shown that quasi-2D physical approximations present in classical networks cannot reproduce predictions of piston-like displacement, snap-off or layer curvature produced by the VOF simulations. The geometric detail of the GNM is exploited to update common physical approximations in PNMs, accounting for all three spatial dimensions on a pore-by-pore basis. The updated GNM is shown to agree well with VOF results, and the impact on macroscopic predictions at larger scales is explored.

Raeini, A. Q., B. Bijeljic, and M. J. Blunt (2018). Generalized network modeling of capillary-dominated two-phase flow. Physical Review E 97 (2).