A first-ever global permeability map was published last month. The authors "use an extensive compilation of results from hydrogeologic models to show that regional-scale (>5 km) permeability of consolidated and unconsolidated geologic units below soil horizons (hydrolithologies) can be characterized in a statistically meaningful way. The representative permeabilities of these hydrolithologies are used to map the distribution of near-surface (on the order of 100 m depth) permeability globally and over North America."
Mapping permeability over the surface of the Earth, GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L02401, 6 PP., 2011, doi:10.1029/2010GL045565