Seismic Inversion for Ray Impedance and Elastic Parameters for an Inter-bed Reservoir

First we apply the ray impedance inversion to an inter-bed reservoir to characterize the oil-bearing sands. Seismic ray impedance, compared to conventional elastic impedance, has advantages in terms of sensitivity and stability to fluid content in the reservoir. We show that ray impedance with a higher ray parameter is sensitive to different lithologies, and even has the potential for discrimination of fluid content. In addition, we develop a simultaneous inversion to estimate three elastic parameters from PP-wave reflection seismics by using high-order approximation of reflection coefficients. Through the comparison of the inverted parameters with the corresponding well logs, we show that stable and high-resolution results are obtained for Poisson’s ratio and even for density, from which we can identify the reservoir fluid distributions.