This article is based on
Chapter 10 of "The Log Analysis Handbook" by E. R. Crain, P.Eng., published by Pennwell Books 1986 Updated 2004.
webpage version is the copyrighted intellectual
property of the author.
Do not copy or distribute in any form without explicit
Permeability from the
This is one of the oldest permeability methods available, and
is reliable when calibrated to core data.
PERMw = CPERM * (PHIe ^ DPERM) / (SWir ^ EPERM)
CPERM = permeability constant (fractional)
DPERM = porosity exponent (fractional)
EPERM = irreducible saturation exponent (fractional)
PERMw = permeability (millidarcies)
PHIe = effective porosity from any method (fractional)
SWir = irreducible water saturation (fractional)
1. Using Log-Derived Values of Water Saturation and Porosity,
R.L. Morris, W.P. Biggs, SPWLA, 1967.
2. An Investigation of Permeability, Porosity, and Residual Water
A. Timur, SPWLA, 1968
Different researchers have found a variety of exponents based
on core analysis studies, and the analyst may find many more in
the literature or company files.
RESEARCHER CPERM DPERM EPERM
Morris-Biggs 65000 6500 6.0 2.0
Timur 3400 340 4.4 2.0
Assume data from Classic Example Sand B.
PHIe = 0.30
SWir = Sw = 0.25
Wylie-Rose formula / Morris-Biggs parameters:
CPERM = 62500
DPERM = 6.0
EPERM = 2.0
PERMw = 62500 * (0.30 ^ 6) / (0.25 ^ 2) = 730 md
Permeability from Morris - Biggs parameters
Permeability from Timur parameters
Permeability Calculated from Various Methods