title: Flow coupling during three-phase gravity drainage.
abstract: We measure the three-phase oil relative permeability k(ro) by conducting unsteady-state drainage experiments in a 0.8 m water-wet sand pack. We find that when starting from capillary-trapped oil, k(ro) shows a strong dependence on both the flow of water and the water saturation and a weak dependence on oil saturation, contrary to most models. The observed flow coupling between water and oil is stronger in three-phase flow than two-phase flow, and cannot be observed in steady-state measurements. The results suggest that the oil is transported through moving gas-oil-water interfaces (form drag) or momentum transport across stationary interfaces (friction drag). We present a simple model of friction drag which compares favorably to the experimental data.
authors.affiliation: Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, Texas 78712, USA.
authors.forename: H
authors.initials: H
authors.lastname: Dehghanpour
authors.forename: B
authors.initials: B
authors.lastname: Aminzadeh
authors.forename: M
authors.initials: M
authors.lastname: Mirzaei
authors.forename: D A
authors.initials: DA
authors.lastname: DiCarlo