Non-linear AVO inversion based on a novel exact PP reflection coefficient

The Zoeppritz equations describe the relationship between the amplitudes of the P-wave incident waves and the PP or PS reflected waves. Various Zoeppritz approximations are widely used for Pre-stack seismic inversion. Nevertheless, the approximations are limited in the case of critical angle and high contrast situations. Although the Zeoppritz equations break through the constraint of weak contrast between layers and can be applied for elastic parameters varying severely, the difficulty of inverting for six parameters (P- and S-wave velocities, as well as density between layers) and the intrinsic nonlinearity of Zoeppritz equation make it less appropriate in practical applications. Given this problem, the novel Zoeppritz-based nonlinear equation can be obtained by means of the velocity and density terms of each layer were replaced by the P- and S-wave velocities and density reflectivity respectively. The model test and real seismic data verified the feasibility and suitability of this novel exact PP reflection coefficient.