ABSTRACT
Chapter 4 covered the absolute permeability of the reservoir rock, which by definition signifies that the rock pore space is fully saturated by a single-phase fluid. However, petroleum reservoirs are seldom such simple single-phase fluid systems, that is, the pore space is typically distributed between either two (gas-water or oil-water) or three fluid phases (gas-oil-water). In some rare cases, along with the fluid phases, a solid organic phase such as asphaltenes may also distinctly exist at certain reservoir conditions; readers are referred to an excellent text by Mullins1 on this topic. Hence, considering the existence of multiple fluid saturations in a petroleum reservoir, other definitions must be added for a complete classification of the properties of a petroleum reservoir. All the chapters from this point onward deal with properties of petroleum reservoir rocks permeated with multiple fluid saturations.
