title: Oscillation-induced displacement patterns in a two-dimensional porous medium: a lattice Boltzmann study.
abstract: We present a numerical study of the statistical behavior of a two-phase flow in a two-dimensional porous medium subjected to an oscillatory acceleration transverse to the overall direction of flow. A viscous nonwetting fluid is injected into a porous medium filled with a more viscous wetting fluid. During the whole process sinusoidal oscillations of constant amplitude and frequency accelerates the porous medium sideways, perpendicular to the overall direction of flow. The invasion process displays a transient behavior where the saturation of the defending fluid decreases, before it enters a state of irreducible wetting fluid saturation, where there is no net transport of defending fluid toward the outlet of the system. In this state the distribution of sizes of the remaining clusters are observed to obey a power law with an exponential cutoff. The cutoff cluster size is found to be determined by the flow and oscillatory stimulation parameters. This cutoff size is also shown to be directly related to the extracted amount of defending fluid. Specifically, the results show that the oscillatory acceleration of the system leads to potentially a large increase in extracted wetting fluid.
authors.affiliation: Department of Physics, University of Oslo, Blindern, NO-0316 Oslo, Norway. olav.aursjo@fys.uio.no
authors.forename: Olav
authors.initials: O
authors.lastname: Aursjø
authors.forename: Henning Arendt
authors.initials: HA
authors.lastname: Knudsen
authors.forename: Eirik G
authors.initials: EG
authors.lastname: Flekkøy
authors.forename: Knut Jørgen
authors.initials: KJ
authors.lastname: Måløy