Simultaneous Inversion for Elastic Parameters Using PP- and PS-waves Jointly in the Ray Parameter Domain

In seismic inversion for P-wave velocity, S-wave velocity and density simultaneously, it is difficult to solve the density parameter. We develop a simultaneous inversion by using PP- and PS-wave reflection coefficients jointly in the ray parameter domain. Before joint inversion,we need to appropriately calibrate two input data sets both in space and time with their true amplitudes. We show that the simultaneous inversion is superior in terms of accuracy and stabilization when compared to inversion using PP-wave alone. We apply the simultaneous inversion on a tight-sand gas reservoir. With the well-calibrated PP- and PS- waves and appropriately designed weighting factors, we are able not only to invert high-resolution P- and S-wave velocities, but also to estimate density accurately from which reservoir distribution can be identified.