Changes

==Preparing multiphase flow properties==

==Preparing multiphase flow properties==

[[file:conducting-a-reservoir-simulation-study-an-overview_fig2.png|thumb|{{figure number|2}}(a) Pseudo-relative permeability and (b) capillary pressure curves calculated for two-layer thicknesses compared to laboratory measurements. (From Coats,<ref name=pt10r6>Coats, K. H., 1967, Simulation of three-dimensional, two-phase flow in oil and gas reservoirs: Society of Petroleum Engineers Journal, Dec., p. 377–388; Transactions, AIME, v. 240.</ref>, after <ref name=pt10r22 /> © 1967, 1990 Society of Petroleum Engineers.)]]

[[file:conducting-a-reservoir-simulation-study-an-overview_fig2.png|thumb|{{figure number|2}}(a) Pseudo-relative permeability and (b) capillary pressure curves calculated for two-layer thicknesses compared to laboratory measurements. (From Coats,<ref name=pt10r6>Coats, K. H., 1967, Simulation of three-dimensional, two-phase flow in oil and gas reservoirs: Society of Petroleum Engineers Journal, Dec., p. 377–388; Transactions, AIME, v. 240.</ref>, after Mattax & Dalton,<ref name=pt10r22 /> © 1967, 1990 Society of Petroleum Engineers.)]]

Fluid saturations and the produced fractions of oil, gas, and water are determined by [[capillary pressure]]s and relative permeabilities specified as functions of water saturation. Equilibrium (initial) fluid saturations are directly dependent on capillary pressure, which is itself a function of height above the [[fluid contacts]], the fluid densities, porosities, permeabilities, and the surface chemistry of the fluids. Once production or injection commences, fluid movement is controlled by the [[relative permeability]] of each phase (except at very low velocities where the effects of capillary pressure are important). In a reservoir consisting of two fluid phases, oil-water, gas-oil, or gas-water capillary pressures and relative permeabilities must be specified. For a three-phase system, relative permeabilities and capillary pressures for two of the three possible systems are specified.

Fluid saturations and the produced fractions of oil, gas, and water are determined by [[capillary pressure]]s and relative permeabilities specified as functions of water saturation. Equilibrium (initial) fluid saturations are directly dependent on capillary pressure, which is itself a function of height above the [[fluid contacts]], the fluid densities, porosities, permeabilities, and the surface chemistry of the fluids. Once production or injection commences, fluid movement is controlled by the [[relative permeability]] of each phase (except at very low velocities where the effects of capillary pressure are important). In a reservoir consisting of two fluid phases, oil-water, gas-oil, or gas-water capillary pressures and relative permeabilities must be specified. For a three-phase system, relative permeabilities and capillary pressures for two of the three possible systems are specified.