Permeability

Permeability is a property of a porous material's ability to allow fluids to pass through it. It is often represented by the (italicized) Greek letter κ (kappa), but can also be expressed in terms of the intrinsic permeability to fluid flow of a porous medium. The permeability of a medium is related to the porosity, but also to the shapes of the pores in the medium and their level of connectedness.

Definition

Permeability in fluid mechanics and the Earth sciences (commonly symbolized as κ, or k) is a measure of the ability of a porous material (often, a rock or an unconsolidated material) to allow fluids to pass through it.

Units

In the International System of Units (SI), permeability is measured in square meters (m²). A practical unit for permeability is the darcy (D), or more commonly the millidarcy (mD).

Permeability in Earth sciences

In Earth sciences, permeability is the measure of the ability of a material (typically, a rock or unconsolidated material) to transmit fluids through it. It is of primary importance in the field of hydrogeology, petroleum geology and geothermal energy.

Permeability in materials science

In materials science, permeability is the measure of the ability of a material to support the formation of a magnetic field within itself, otherwise known as distributed inductance in transmission line theory. Hence, it is the degree of magnetization that a material obtains in response to an applied magnetic field.

See also

• Hydraulic conductivity
• Permeation
• Permeance
• Permeameter
• Darcy's law
• Intrinsic permeability
• Relative permeability