ABSTRACT
The first published information concerning the simultaneous flow of multiple fluid phases was probably by Hassler et al. The term "relative permeability" had not yet been coined and Hassler et al. studied only the flow characteristics of the gas phase as a function of fluid saturation in consolidated rocks. Water-oil relative permeability is usually plotted as a function of water saturation. Unfortunately, there is an alternate definition of relative permeability currently in use. This terminology defines the oil relative permeability at irreducible water saturation as having a value of one, and defines absolute permeability as the effective permeability at irreducible water saturation. Gas-oil relative permeability and gas-liquid relative permeability are similar in concept to water-oil relative permeability. The preferred relative permeability values are those taken with connate water present at the irreducible saturation value. An experimental procedure to determine relative permeability in an unconsolidated sand was first described by Wyckoff and Botset.
