On Solitary Shock Waves for Solute and Fluid Pressure in Geologic Porous Media

A novel model about mechanic and chemo-poroelastic (osmosis) coupling of fluids and solutes in fluid saturated porous media is here presented. This model is focused on non linear phenomena and does not apply the Osanger symmetry. Analyzing the action of a strong external stress we obtain two coupled non-linear equations for fluid pressure and solute (salt or pollutant) concentration. Their solutions in clay or shales unveil an unexpected presence of quick, non linear, strong transients of coupled pressure and solute, known in physics as Burger solitions. The presence of solitons may shed new light on flow processes, as about the origin of large hyperpressures.We also tested our model for sandstones assuming that a small, or very small, osmotic behavior could be there present. We found that Burgers solitons can be present in sandstones or other higher permeability rocks, as some Calabria rocks.