Acoustic porosity

Wylie (Anhydrite, Basalt, Chalk, Claystone, Coal, Dolomite, Halite, Limestone, Marl, Sandstone, Shale, Siltstone)

185 in μs/ft

Raymer-Hunt-Gardner (Anhydrite, Basalt, Chalk, Claystone, Coal, Dolomite, Halite, Limestone, Marl, Sandstone, Shale, Siltstone)

1.6 is a non-dimensional constant.

0.0025 in μs/ft

Modified Chapman (Anhydrite, Basalt, Chalk, Claystone, Coal, Dolomite, Halite, Limestone, Marl, Sandstone, Shale, Siltstone)

0.698 is unitless