Geostatistical AVO Direct Facies Inversion

Abstract

In seismic reservoir characterization one aims to derive petrophysical properties of hydrocarbon reservoir conditioned to both available well-log and seismic reflection data. In this paper we present a new global pre-stack seismic AVO inversion methodology that inverts pre-stack seismic data directly for density, p-wave velocity, s-wave velocity and facies models. The retrieved subsurface models are able to reproduce the high vertical resolution of the well-log data with the spatial coverage of the seismic data. This new approach is based on an iterative genetic algorithm where the perturbation is done recurring to geostatistical simulation and co-simulation. The inverted facies model is an intrinsic part of the solution and represents the link between the elastic models (observed seismic) and the subsurface geology.