Impact of reservoir conditions on CO2-brine relative permeability in sandstones

We demonstrate experimentally, that the spatial distribution of fluids in the pore space is the primary control on CO2 relative permeability, and that the importance of spatial heterogeneity in rock properties such as capillarity, porosity and permeability on fluid distributions is controlled by viscous forces. The importance of viscous forces during drainage core floods is evaluated using fluid viscosity as the varying parameter in CO2-brine core floods, and flow rate in N-2-water core floods. A transition from a heterogeneous to a homogeneous displacement is observed with increasing viscous force applied to the core. During capillary dominated core flooding the relative permeability is sensitive to flow rate and viscosity. Homogeneous displacements have an invariant relative permeability and as such are a measure of the true relative permeability of the rock. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).