Bound water in Clay and Shale and its influence on P- and S-wave Velocities

Molecular scale numerical modelling shows that water molecules tend to align with each other into an ordered structure near charged surfaces. The simulations imply that intercalated water and water on clay mineral surfaces will have elastic properties that differ from those of free water; in particular that this bound or adsorbed water will have shear stiffness. Rock physics modelling incorporating bound water properties provide a good fit to controlled experiments on clay and on clay-rich shales.