Applicability of AVO Inversion Based on Effective Reflection Coefficients to Long-offset Data from Curved Interfaces

AVO inversion is an essential and powerful interpretational tool. However, conventional AVO-inversion workflow in application to long-offset data will unlikely succeed, because it is limited to relatively plane interfaces, weak parameter contrasts and moderate incidence angles, where the offset dependence of the reflection amplitude can be described by linearized plane-wave reflection coefficients (PWRCs). It is also known that the PWRC is insensitive to the interface curvatures and breaks down at the near-critical offsets, where the head wave is generated, as well as at the post-critical offsets, where the reflected and head waves interfere. To avoid these inconsistencies, we exploit effective reflection coefficients (ERCs) that generalize PWRCs for curved interfaces and nonplane waves. Based on our previous results for plane interfaces, we generalize the improved approach to AVO inversion for the curved interfaces. Using a synthetic data example, we also show that the theoretical description of the actual reflection from a curved interface is directly applicable in AVO inversion.