A Statistical Study of Reservoir Permeability: Distributions, Correlations, and Averages

The authors propose that reservoir permeability may be statistically distributed in a variety of ways. Two hypothetical cases of reservoir layering are statistically analyzed. This analysis suggests that a restricted family of functions - all related to the normal distribution - can be used to represent permeability distributions. The log-normal distribution is one member of the family. Several sets of field data are analyzed. The analyses show that (1) permeability data are not necessarily log-normally distributed, (2) all the permeability distributions considered are closely approximated by members of the proposed family of functions, and (3) improved porosity/permeability relationships result when the permeability distribution is known.