@wikipedia
A measure of ability of a porous formation to allow a certain fluid to pass through it.
For the laminar flow:
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| k_f = \mu_f \cdot \frac{| {\bf v}|}{ | \nabla p |} |
where |
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Permeability depends on fluid type, filling the porous media and the fluid type which is sweeping through it which leads to splitting its value into a product of two components:
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k = k_a \cdot k_r |
where
In general case, permeability is anisotropic both in vertical and lateral directions and quantified by symmetric tensor value:
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anchor | ktensor |
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alignment | left |
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k=\begin{bmatrix}
k_{11} & k_{12} & k_{13} \\
k_{12} & k_{22} & k_{23} \\
k_{13} & k_{23} & k_{33}
\end{bmatrix} |
which can be diagonalized for a proper selection of coordinate axis
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body | ({\bf e_1}, {\bf e_2}, {\bf e_3}) \rightarrow ({\bf e_x}, {\bf e_y}, {\bf e_z}) |
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k=\begin{bmatrix}
k_x & 0 & 0 \\
0 & k_y & 0 \\
0 & 0 & k_z
\end{bmatrix} |
and characterized by 3 principal tensor components
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body | k = (k_x, \, k_y, \ k_z) |
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If not mentioned otherwise the permeability usually means absolute horizontal permeability:
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body | k = k_h = \sqrt{k_x^2+k_y^2} |
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See also
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Natural Science / Physics / Fluid Dynamics / Percolation
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Field Study & Modelling
[ Petrophysics ] [ Basic reservoir properties ] [ Wettability ] [ Permeability ] [ Absolute permeability ] [ Horizontal permeability ] [ Vertical permeability ] [ kv/kh ]
[ Relative permeability ]