SEGJ Technical Conference

Study on rock physical interpretation of shallow geophysical data Part IV - Study on rock physics models for interpreting static moduli of soft sedimentary rocks-

Abstract To interpret static moduli of the soft sedimentary rocks, the static Youngs moduli are calculated with the sandy shale model of the binary sand/shale mixture model and compared to the measurement data in the laboratory mechanical tests of the rock core samples. The static modulus for the rock is calculated by the Hashin-Strikman lower bound, Hertz-Mindlin contact model and Gassmann equation. In the Hertz-Mindlin contact model, the shear modulus is calculated by incorporating the mixture of frictional and frictionless grain contacts into the model. The calculated static Youngs moduli are well consistent with the measured data in the laboratory for three different soft sedimentary rocks. This result demonstrates that the rock physics model can be used to predict the static moduli required in civil engineering applications from dynamic ones obtained from seismic velocities.