Removing absorption effect on AVO via inverse Q filtering in offset direction

Abstract

Summary Seismic wave propagation in a viscoelastic medium suffers from energy attenuation and velocity dispersion. The earth absorption not only decreases seismic resolution, but also distorts the amplitude variation with offset (AVO). Inverse Q-filtering is a technique commonly used to remove these absorption effects. However, its application often suffers from instability in the presence of noise. In this paper, we decompose the absorption into two independent components, namely the offset and depth components. They have similar mathematical expressions, but different effective dissipation factors. The former is mainly responsible for seismic event variation in offset direction, while the latter is mostly responsible for the decreased resolution in depth direction. On the assumptions of horizontally stratified medium and small incidence angle, we derived the mathematical expression of effective dissipation factor both in offset and depth directions and implemented absorption compensation in offset direction by an inversion scheme proposed in this paper to restore the distortion of the AVO trend introduced by absorption. Synthetic model tests are used to examine its effectiveness and feasibility.