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Relative permeability must be between zero and one. In applications, relative permeability is often represented as a function of water saturation; however, owing to capillary hysteresis one often resorts to a function or curve measured under drainage and another measured under imbibition.
Craig [1] proposed three rules of thumb for interpretation of wettability from relative permeability curves. These rules are based on the value of interstitial water saturation, the water saturation at the crossover point of relative permeability curves (i.e., where relative permeabilities are equal to each other), and the normalized water permeability at residual oil saturation (i.e ...
In SI units, permeability is measured in henries per meter (H/m), or equivalently in newtons per ampere squared (N/A 2). The permeability constant μ 0, also known as the magnetic constant or the permeability of free space, is the proportionality between magnetic induction and magnetizing force when forming a magnetic field in a classical vacuum.
in which is the absolute permeability, is the relative permeability, φ is the porosity, and μ is the fluid viscosity. Rocks with better fluid dynamics (i.e., experiencing a lower pressure drop in conducting a fluid phase) have higher TEM versus saturation curves.
A closely related parameter is the permeability, which expresses the total magnetization of material and volume. The volume magnetic susceptibility , represented by the symbol χ v (often simply χ , sometimes χ m – magnetic, to distinguish from the electric susceptibility ), is defined in the International System of Units – in other ...
A practical unit for permeability is the darcy (d), or more commonly the millidarcy (md) (1 d ≈ 10 −12 m 2). The name honors the French Engineer Henry Darcy who first described the flow of water through sand filters for potable water supply. Permeability values for most materials commonly range typically from a fraction to several thousand ...
Permeability (earth sciences), a measure of the ability of a material (such as rocks) to transmit fluids Relative permeability, in multiphase flow in porous media; Permeability (foundry sand), a test of the venting characteristics of a rammed foundry sand; Hydraulic conductivity, the permeability of soil for water
The typical relative permeability (μ r) of electrical steel is 4,000-38,000 times that of vacuum, compared to 1.003-1800 for stainless steel. [ 15 ] [ 16 ] [ 17 ] The magnetic properties of electrical steel are dependent on heat treatment , as increasing the average crystal size decreases the hysteresis loss.