The Giant Forgotten Sub-Salt Hydrocarbon Province in the Greater Campos Basin, Brazil: A Journey from a Great Mistake to a Learning Experience

M.R Mello¹, Paul Willian Brooks¹, J.M Moldowan², and B. Wygrala^3
1 HRT & Petroleum, Rio de Janeiro, Brazil
² Biomarker Technology, Sebastopol, Ca
³ IES-Integrated Exploration System, Juelich, Germany

In most areas of the shallow to ultra-deep water of the Greater Campos province, composed of the Santos, Campos and Espírito Santo Basins, exploration is far from being complete since deep, Lower Cretaceous pre and post-Rift coquinas, sandstones and carbonate reservoirs have not being thoroughly explored.

Although almost 100% of all known hydrocarbon reserves (around 15 billion bbl) were sourced by pre-rift lacustrine source rocks, less than 2% of them is found in any of the Lower Cretaceous reservoirs.

At early exploration stages, the pre-rift reservoirs were targeted giving satisfactory results allowing the Basins to become productive. Later, with the discovery of the super-giant Tertiary turbidities systems, the Lower Cretaceous petroleum system was forgotten.

This study, based in an integrated multidisciplinary approach using technologies ranging from molecular geochemistry to 3D seismic and compositional petroleum system modeling, suggest the occurrence of a super-giant hydrocarbon province in the Lower Cretaceous pre and post-salt reservoirs of the Greater Campos Basin, Brazil.

In the last years, several companies started to drill deeper, greater then 6000 m, looking for Lower Cretaceous petroleum systems in the Greater Campos Basin. Preliminary outstanding results indicate that a lesson must be learned in the area: If there is an overcharged deep source rock system, directly associated with good quality deep reservoir rocks, giant light oil accumulations almost certainly will be present. Therefore let's go deep!