Impacts of Pore Network?Scale Wettability Heterogeneity on Immiscible Fluid Displacement: A Micromodel Study

The mixed-wet nature of reservoir formations imposes a wide range rock wettability from strong resident-fluid wetting to invading-fluid wetting. characteristics two-phase flow in porous media composed mixed-wetting surfaces remain poorly understood. In this study, we investigated the displacement resident ethylene glycol (EG) by hexane two micromodels identical 2.5-D geometry heterogeneity, with uniformly or heterogeneously distributed patches strongly hexane. These are mixed among pores unaltered EG-wetting surfaces. Along control tests originally EG-wet micromodel, show classic fingering and transitions regimes at (capillary number) ?7.2 ?3.9. Moreover, pore-scale distributions their spatial correlation influence efficiency. micromodels, found (a) an increase steady-state saturation end experiments up 0.12 capillary regime decrease most 0.06 viscous regime, compared (b) dispersed fragmented distribution after displacement. Brine drainage during supercritical CO2 (scCO2) injections these occurs lower contrasts, under similar viscosity ratios interfacial tensions resulted higher efficiency relative EG While mixed-wettability can enhance uniform wettability, dynamics immiscible fluids reservoirs expected be less pronounced contributing geological sequestration, oil recovery, remediation hydrocarbon-contaminated aquifers.