Incorporating Seismic Velocity Data in AVO/AVA Low Frequency Models by Honoring Local Geology

Low frequency information is required for quantitative reservoir characterization. Because borehole measurements are laterally sparse and preferential towards reservoir locations, there is much uncertainty on the low frequency models away from well control. Methods to improve the reliability of the low frequency data include the use of low frequency update schemes or seismic attribute maps. The use of seismic velocity data for trend modeling is well recognized, but the methodology for incorporating the velocity is not always clearly described. Especially in case of an AVO/AVA study, where low frequency information for several elastic properties is required, a rigorous workflow is desired. Here, we propose a method to include seismic velocity data. The methodology uses local geological knowledge through rock physics relations. We validate the method by comparing results of a more common method with our proposed workflow at blind wells. This shows that a low frequency model that does not use the velocity data misses significant lateral variations that are representative of the local geology.