Deepwater Depositional Architecture and Evolution in the Rio Muni Basin, West Africa

On the basis of high-resolution 2D and 3D seismic data as well as some well data, an integrated seismo-stratigraphic study was carried out in deepwater area of the Rio Muni basin in order to define and understand the Cretaceous stratigraphic framework, deepwater depositional system and reservoir potential of the Rio Muni basin.

The analysis of seismic facies and seismic attributes indicate deepwater depositional systems are well developed in the Cretaceous (Albian- Maastrichtian) stratigraphic interval in the study area of the Rio Muni basin. And architectural elements mainly include channel complexes, frontal splays, levee-overbank sediments, Mass transport complexes and pelagic drape complexes ranging from base of slope facies to basin floor facies.

The investigation of depositional evolution suggests that the Rio Muni basin experienced retrogradation during the Albian- Turonian and gradual progradation during the Turonian- Maastrichtian. Controlled by the depositional evolution, the Santonian- Maastrichtian frontal splays and channel complexes are likely to be the best reservoir targets in the study area.