GMI-Literature-Phi

UCS = 40144 e(^–10Φ)

where:

40144 is in psi.

-10 is a non-dimensional constant.

This equation is derived from a synthesis of published laboratory data using 105 samples with measured UCS of 300–52,000 psi and porosity between 0.2 and 33 percent, although the nature of the samples and the laboratory procedures are not well defined. The equation works better than the modified Vernik formula, particularly for high porosity sandstones.