Three-term AVO waveform inversion

Density reflectivity is a desirable AVO attribute sought by the explorationist since it has the potential to say something about the fluid saturation. However accurate density reflectivity estimates are difficult to obtain due to the ill-conditioned nature of the inverse problem. A small amount of noise will lead to large errors in the estimates. To improve the stability of the inversion, large angles and offsets are required but these bring their own problems. One set of related problems is NMO stretch and offset dependent tuning. This paper develops and demonstrates an AVO waveform inversion that incorporates into its forward model these factors allowing for accurate estimates even in their presence. Well constraints and various regularization strategies are employed to further enhance the reliability of the solution