Quantitative Seismic Interpretation of a Class-1 AVO Turbiditic System Located Offshore Cote d’Ivoire, West Africa

Abstract

This paper presents a case study where a Class-1 AVO turbiditic system located offshore Cote d'Ivoire, West Africa, was characterized in terms of rock properties (lithology, porosity and fluid content) and stratigraphic elements using well log and prestack seismic data. The methodology applied involves, 1) the conditioning and modeling of well log data to several plausible geological scenarios at the prospect location, 2) the conditioning and inversion of prestack seismic data for Pand S-wave impedance estimation, and 3) the quantitative estimation of rock property volumes and their geological interpretation. The approaches used for the quantitative interpretation of these rock properties were the multi-attribute rotation scheme (MARS) for lithology and porosity characterization, and a Bayesian litho-fluid facies classification (SRPstatistical rock physics) for a probabilistic evaluation of fluid content. The result shows how the application and integration of these different AVO-and rock physics-based reservoir characterization workflows help to understand key geological stratigraphic elements of the architecture of the turbidite system and its static petrophysical characteristics (e.g. lithology, porosity, and net sand thickness). Furthermore, we show how to quantify and interpret the risk related to the probability of finding hydrocarbon in a Class-1 AVO setting using seismically-derived elastic attributes, which are characterized by having a small level of sensitivity to changes in fluid saturation.