GMI-Jizba-M (Jizba, 1991)

UCS = 3648 e(M ´ 3.65e ^{– 7})

where:

3648 is in psi.

3.65 is in 1/psi.

The equation is based on laboratory test data from Travis Peak, Texas shaley sandstones analyzed by Jizba (Stanford PhD thesis, 1991). The sample data was derived from low to medium porosity, low permeability, consolidated sandstones (1% < phi < 18%). M in this formula is calculated from static measurements and therefore the equation should only be applied to tight sandstones with M_static » M_dynamic, or with a known dynamic-static correction factor. The measurements were carried out on dry samples and therefore, corrections to the value of M for fluid compliance effects are required in fluid-saturated sandstones.