Joint Inversion Based P/S Wave Velocity Data Processing to Test a New Rock Physical Model Describing Acoustic Hysteresis

Understanding the relationship between pressure and rock physical parameters, such as acoustic velocities, elastic moduli, porosity is essential for exploring and exploiting of natural reserves. In this paper we introduce a rock model which describes the acoustic P, S wave velocities-pressure relationship for loading and unloading phases as well as explains the mechanism of acoustic hysteresis. After Birch we assume that the main factor determining the pressure dependence is the closure of pores. The advantage of the model is that it is not based on simple curve fitting, but gives physical explanation for the process with three-parameter exponential equations. Laboratory measured acoustic P and S wave velocities as a function of pressure were inverted to prove the applicability of the model and to obtain that of parameters. The uniaxial loading of the samples was carried out by an automatic acoustic test system. The quality checked joint inversion results showed that the calculated data matched accurately with measured data and also proved that the suggested petrophysical model performs well in practice.