There is a statistical correlation between absolute permeability k_a and effective porosity \phi = \phi_e which can be approximated by various permeability-porosity models
The most generic approach to permeability modelling is based on the concepts of Flow Zone Indicator FZI, Rock Quality Index RQI and normalised porosity \phi_r:
(1) | k = 1014.24 \cdot \phi \cdot RQI^2 |
(2) | RQI = FZI \cdot \phi_r |
(3) | \phi_r = \frac{\phi}{1-\phi} |
(4) | k = 1014.24 \cdot FZI^2 \cdot \frac{\phi^3}{( 1 - \phi)^2} |
In case FZI = \rm const for each lithofacies the model (4) represents conventional Cozeny-Karman permeability @model
In a more general case, the Flow Zone Indicator keeps dependance on variation of shaliness and effective porosity within a given lithofacies:
(5) | FZI =FZI(V_{sh}, \, \phi) |
but not as strong as permeability and with a better separation between lithofacies which makes it easier to pick up the correlation.
Below is the list of popular permeability-porosity correlations also called PORO-PERM correlations:
See also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Petrophysics / Absolute permeability