Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 247, part 1
Modeling Dielectric-constant Values of Geologic Materials: An Aid to Ground-penetrating Radar Data Collection and Interpretation--Fig. 9B

Fig. 9B. Hydraulic (air) permeability versus helium porosity, with a log-linear correlation of R₂ = 0.92 (line, excludes siltstone samples). These values are based on laboratory measurements from Tonganoxie Sandstone estuarine sandstone, shaly sandstone, siltstone, and shale samples.