Capillary-driven instability of immiscible fluid interfaces flowing in parallel in porous media

Abstract

When immiscible wetting and nonwetting fluids move in parallel in a porous medium, an instability may occur at sufficiently high capillary numbers so that interfaces between the fluids initially held in place by the porous medium are mobilized. A boundary zone containing bubbles of both fluids evolves, which has a well-defined thickness. This zone moves at constant average speed toward the nonwetting fluid. A diffusive current of bubbles of nonwetting fluid into the wetting fluid is set up.

Mechanisms controlling fluid breakup and reconnection during two-phase flow in porous media

“…These clusters are referred to as ganglia and the phenomenon is broadly described as ganglion dynamics [9,10]. This has been observed to occur at high fluid flow rates, where viscous forces dominate over capillary forces [8,[10][11][12][13]. Increasing the viscous force results in increased breakup and ganglia advection.…”

Towards a thermodynamics of immiscible two-phase steady-state flow in porous media

“…3, where the two regions have initially been filled with (partially) wetting and nonwetting fluids, respectively. As time progresses, there is cluster formation and the two fluids mix at this level [19]. Eventually, the two regions attain the same saturation level and all statistical distributions become stationary: the two regions now have the same temperature.…”