Joint PP-PS seismic prestack inversion of thin-bed reservoirs

Abstract

Abstract Thin beds are significant targets in seismic exploration of lithological reservoirs. The conventional Amplitude Versus Offset/Angle (AVO/AVA) inversion methods are based on Zoeppritz equations and their approximate formulas under single-interface assumptions, which are not suitable for thin-bed problems. Therefore, AVO/AVA inversion methods for thin-bed reservoirs are needed in high-resolution seismic exploration. Based on approximate reflection coefficients of a thin bed, this paper proposes a joint PP-PS prestack inversion method of thin-bed reservoirs using a least-squares approach. The method directly predicts elastic properties, including P-wave velocities, S-wave velocities and densities, as well as thin-bed thickness. In this study, four typical thin-bed models and an actual thin coal seam were used to prove applicability and superiority of the given inversion procedure. Compared to prestack inversion methods using exact Zoeppritz equations, our inversion method reveals thin-bed existence precisely, gives higher estimation accuracy and has better noise robustness. Future applications of the proposed inversion method are expected to advance seismic reflectivity techniques of thin-bed reservoirs, making it possible to detect potential source reservoirs with higher precision and accuracy.