The absolute permeability of another material can be expressed relative to the permeability of free space. Absolute Permeability; 푲̅= 푲휼 휸풘 퐾̅ = absolute permeability K = hydraulic conductivity 훾푤 = unit weight of water 휂 = viscosity of water. The relative permeability of a magnetic material, designated μ r , is the ratio of its absolute permeability μ to that of air μ o . Absolute permeability (aka intrinsic or specific permeability) ... A darcy and millidarcy are units of permeability, named after Henry Darcy. This coefficient not only depends on the properties of water but also depends on the properties of soil. 4. The units for the coefficient of absolute permeability can be obtained by substituting the units on the right-hand side of Eq. Absolute Permeability is the measure of the ease of flow of a fluid through the reservoir rock. This, however, is the absolute permeability and can either be measured by using air (gas; if gas is used a Klinkenberg correction needs to be applied) or mercury. Absolute or intrinsic permeability (Ka) is measured with a single fluid in the rock. Second, one must take note if the measurement is in an invaded zone with two phases and, hence, the permeability determined is an effective permeability, not an absolute permeability. FACTORS AFFECTING Numerous factors affect the magnitude and the direction of permeability . The absolute permeability reflects 100% saturation of rock by a single fluid whereas the effective permeability to a fluid phase is based upon the presence of two or three fluid phases in porous medium. (9.4). Methods of Computing Coefficient of Permeability. Relative permittivity, also known as the dielectric constant, is the ratio of the absolute permittivity of a material to the vacuum permittivity. The absolute permeability is a property of the rock and is essentially the permeability measured with single phase or at 100% single phase saturation. Permeability in linear materials owes its existence to the approximation: