Reservoir property estimation incorporating prestack inversion and rock physics theory

Estimation of reservoir properties from seismic data is essential for reservoir characterization. The estimation isn't always easy because of the complex and nonlinear relationship between seismic data and reservoir properties. In this study, we develop a strategy to estimate reservoir properties with prestack seismic inversion and rock physics theory. We derive a two-term approximation of Zoeppritz equations to linearize the relationship between seismic data and elastic data. In the framework of the Bayesian theory, a probabilistic prestack seismic inversion method is established to invert elastic parameters. Then, a reservoir parameter coordinate system is built based on rock physics models to transform elastic parameters into reservoir parameters. Contours of inverted elastic parameters are calculated and reservoir parameters are estimated by the intersections of contours. Constraints are added into the objective function to reduce the uncertainties brought by the seismic inversion. Tests on model data and real data have proved the rationality and applicability of the strategy.