Shale-GMI-Literature-Phi

UCS = 41.5 x Φ^–1.762

where

41.5 is in psi.

This equation is derived from a synthesis of published data on 33 samples, with 29 samples having measured core porosities greater than 27%. No information about the nature of samples and test procedures is available. Accurate determination of porosity in shales could be a problem when using this equation.