Pseudo-elastic Impedance Calibrated to Rock Physics Models for Efficient Lithology and Fluid Mapping from AVO Data

We have shown how we can derive attributes similar to elastic impedances, which we refer to as pseudo-elastic impedances, directly from rock physics templates of AI versus Vp/Vs, without knowing the density. This allows us to calibrate the elastic impedances to local rock physics models, and to honour the curvature of rock physics models, normally associated with compaction trends. In areas with large variability in burial depth, it is important to honour the true variability of the background trend. The final regression models are easy to implement in quantitative interpretation workflows, and allow for quick mapping of fluid or lithology anomalies that are consistent with rigorous rock physics models. We have demonstrated the validity of this approach on well log and seismic data from a prospective area in the Norwegian Sea.