Rock physics modeling is an efficient approach to predict elastic properties. Prediction of seismic velocities is more difficult in carbonates compared with clastics because of carbonates heterogeneities due to their complex pore structure. Pore shape appears to be the dominant factor in carbonate rock physics. Therefore, to adequately characterize carbonate reservoir rocks, it is critical to developing a rock physics model capable of handling different pore types. In this study, Xu and Payne’s model were used to predict P- and S-wave velocities, density, acoustic impedance, and Poisson’s ratio to discriminate lithologies in a carbonate reservoir. Besides, predicted elastic properties are compared with measured ones. Accordingly, to be sure that predicted parameters of the model are accurate, different lithologies as limestone, dolomite, and shale have been identified by such comparison and cross-plot analysis.