Applications and Limitations for Rock Physics and AVO in West Africa

Rock physics has been successfully applied off-shore West Africa and it has helped to get a better understanding of the main factors governing the seismic response in this area. Rock physics draws its strength from the power of integration of two complementary sources of information: • localized but vertically very detailed borehole data (logs, PVT, core, etc) and • spatially regularly sampled 3D seismic data (pre-stack, post-stack, angle stacks, etc). The ultimate goal of rock physics is to understand the seismic record in a more quantitative manner at and away from well control. Rock physics attempts to predict lithology and/or fluid properties to support the exploration and development process. In West Africa the seismic record is significantly deteriorated in some areas by the attenuation caused by isolated or stacked gas intervals. That cannot easily be compensated for. In such areas the reliability of the outcome of any quantitative seismic based approach is jeopardized. In the low reflectivity areas diffractions were found to be a useful and reliable DHI.