Pore‐filling material and its effect on velocity in rocks

A new method estimates the dependence of P and S velocities in rocks on elastic properties of the pore‐filling material by going beyond Gassmann’s relations and accounting for pore‐filling materials with nonzero shear stiffness. The resulting estimates are in good agreement with experimental data and Gassmann’s relations for values of velocity in water‐saturated rocks predicted from velocity measured on dry rocks. The method successfully predicts the temperature dependence of velocity: (1) in frozen rocks at the ice‐water phase transition, and (2) in rocks saturated with heavy hydrocarbon undergoing solid‐liquid phase transition.