title: Steady-state, simultaneous two-phase flow in porous media: an experimental study.
abstract: We report on experimental studies of steady-state two-phase flow in a quasi-two-dimensional porous medium. The wetting and the nonwetting phases are injected simultaneously from alternating inlet points into a Hele-Shaw cell containing one layer of randomly distributed glass beads, initially saturated with wetting fluid. The high viscous wetting phase and the low viscous nonwetting phase give a low viscosity ratio M=10(-4). Transient behavior of this system is observed in time and space. However, we find that at a certain distance behind the initial front a "local" steady-state develops, sharing the same properties as the later "global" steady state. In this state the nonwetting phase is fragmented into clusters, whose size distribution is shown to obey a scaling law, and the cutoff cluster size is found to be inversely proportional to the capillary number. The steady state is dominated by bubble dynamics, and we measure a power-law relationship between the pressure gradient and the capillary number. In fact, we demonstrate that there is a characteristic length scale in the system, depending on the capillary number through the pressure gradient that controls the steady-state dynamics.
authors.affiliation: Department of Physics, University of Oslo, PB 1048 Blindern, NO-0316 Oslo, Norway. k.t.tallakstad@fys.uio.no
authors.forename: Ken Tore
authors.initials: KT
authors.lastname: Tallakstad
authors.forename: Grunde
authors.initials: G
authors.lastname: Løvoll
authors.forename: Henning Arendt
authors.initials: HA
authors.lastname: Knudsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Ramstad
authors.forename: Eirik Grude
authors.initials: EG
authors.lastname: Flekkøy
authors.forename: Knut Jørgen
authors.initials: KJ
authors.lastname: Måløy
mesh_terms: D003198:Computer Simulation; D008962:Models, Theoretical; D044367:Phase Transition; D016062:Porosity; D012212:Rheology / Q000379:methods*; D012996:Solutions / Q000737:chemistry*; D017155:Wettability
chemical_list: D012996:Solutions