Generalization of Gassmann Equations for Porous Rocks Saturated with a Solid Material - Theory and Applications

Gassmann equations predict effective elastic properties of an isotropic homogeneous bulk rock frame filled with a fluid. This theory has been generalized for an anisotropic porous frame by Brown and Korringa equations. Recently, Ciz and Shapiro (2008) developed a generalization of Gassmann equations for porous media saturated with a solid material. In this paper we present an overview of the new theory and compare to numerical simulations of effective elastic properties of porous rocks filled with an additional solid component. Moreover, we model the effective elastic prroperties of clay-sand mixtures and rocks saturated with heavy oils. The latter application we validate by comparing to experimental data. A very good agreement between numerical and experimental data has been obtained. Thus, this new generalized Gassmann's model is directly applicable as useful rock physics model, e.g.: in proper seismic data interpretation.