From Exploration AVO to Fast-Track Delineation - Example of a Simple Geophysical Workflow

West African deep offshore oil bearing sand reservoirs exhibit elastic parameters distinct from those of the shaly seal rocks they are embedded into. As such, their exploration lends itself to the use of AVO techniques for exploration and/or pre-stack seismic inversion for delineation. This paper makes use of a real data case study to present the Quantitative Interpretation workflow that was used from exploration to delineation, coping with the project fast-track constraints. Numerous authors have highlighted how much the relevance of AVO analysis depends upon the quality of the pre-stack data. Our workflow addresses most of the well known pitfalls of AVO analysis. It builds up on a step by step careful definition, qualification, pre-conditioning and analysis of angle stacks. It leads to the generation of a seismic volume robustly highlighting AVO anomalies to serve exploration purposes. With quantitative seismic-to-well tie, seismic volumes representing relative elastic properties can be readily constructed and combined into a volume that best matches a reservoir property at the well. Such a volume can then be quickly provided to the Geosciences Team in charge of the fast-track delineation. In this case, this workflow represents a fast-track route to guide the reservoir modelling.