Joint AVO Inversion of PP and PS Reflections Using the Reflectivity Method

Abstract

Summary Conventional three-term AVO inversion methods, which based on Zoeppritz approximation, only have accuracy limited to small angles and, it is always not accurate to invert density term. Using the exact Zoeppritz equation helps to extend the applicable angle range and, therefore, improve the accuracy of inversion. However, it is complex for Zoeppritz equation to simulate PS reflections and transmission loss in multilayer. We propose using the “Reflectivity Modelling” method to do AVO inversion. It allows the computation of PS reflections, transmission loss and even internal multiples. For inversion, we calculate the Fréchet derivative matrix analytically and use a joint objective function of PP and PS reflections, following least square error theory. Both synthetic and real data examples demonstrate that the method is an effective means to invert elastic parameters.