The Impact of Pore-Scale Flow Regimes on Two-Phase Relative Permeabilities in Geothermal Reservoirs

Abstract

Two-phase flow conditions are frequently encountered in geothermal reservoirs due to gradients in pressure and temperature. Although Darcy’s law is routinely used in the multiphase flow scenario, the role of pore-scale flow regimes is usually neglected in the estimation of the relative permeabilities, frequently computed using empirical models like the Corey and the Brooks-Corey correlations. In this work, we extend the generalized model for relative permeabilities developed in Picchi and Battiato (2019) to scenarios typical of geothermal reservoirs. We aim at understanding and quantifying the impact that the topology of the flowing phases may have on relative permeability estimates and derive scaling laws for relative permeabilities when the viscosity ratio is very small (i.e., the non-wetting phase is much less viscous compared to the wetting one) as typical in water-steam systems. Finally, we provide preliminary validation of the model with data available in the literature.