Darcy (unit)

Darcy is a unit of permeability, named after Henry Darcy. It is not a SI unit, but still heavily used in petroleum geology and hydrogeology.

Permeability is to have a measure of the ability of fluids to flow through porous media. Like other Permeabilitätseinheiten has the Darcy the dimension of an area, it is approximately equal to notionally clear opening of ( 1 micron ) ².

The permeability of rock is usually expressed in milli darcy (1 mD = 0.001 D), because oil and water reservoirs typically have permeabilities between 5 and 500 mD.

Definition

The Darcy is defined by means of Darcy's law which can be written as follows:

With:

  • - Filter speed in cm / s
  • - Permeability in Darcy
  • - Dynamic viscosity of the liquid in centipoise
  • The distance between A and B in cm

A porous media having a permeability of 1 Darcy thus permits a liquid having a viscosity of 1 centipoise ( 1 mPa · s, the viscosity of water at 20 ° C) under a pressure gradient of 1 atm / cm, a flow rate of 1 cm / s

  • Hydrogeology
  • Oil production
  • Unit (Physics)
Darcy's law
211651
de