Extending AVO inversion techniques

Charles P. Ursenbach, Robert R. Stewart

A software tool is introduced for assessment of AVO inversion techniques. It employs synthetic offset gathers with spike wavelets and models a wide distribution of earth parameters for each lithology. It is used to demonstrate that a wide range of values that can be obtained for a given lithology, and to obtain the limits of accuracy available for two-parameter inversions based on the Aki-Richards approximation. The method of Fatti et al. (1994) is shown to be an improvement on that of Smith and Gidlow (1987). A Full Offset method is introduced and shown to be superior to that of Fatti et al. A generalized Gardner relation is also introduced and applied. It does not yield improved inversion results for P- and S-wave changes, but can be employed to develop new density inversion techniques. The results show promise for the development of a linear density inversion method.