The Super Giant Great Lagoa Feia Petroleum System: The New Frontier of Exploration in the Pre-Salt Sequences of the Great Campos Basin,Brazil

Marcio R. Mello
HRT&Petroleum, Rio de Janeiro, Brazil

In the Great Campos Basin, light oil discoveries are booming since pre-salt exploration started three years ago. Geochemical and geological data, supported by good quality 3D pre-staked seismic and 3D petroleum system modeling and risk assessment, suggest the existence of huge light oil reserves, pooled in stromatolites and coquinas carbonate from the Lower Cretaceous pre-salt sections of the Santos, Campos and Espírito Santo Basins.

Recently discoveries reported by Petrobras, in the Tupy well, indicates volumes of oil in place up to 10 billion barrels in the pre-salt reservoirs. Also, giant light oil accumulations were reported in the pre-salt carbonates below the Marlin and in the Parque das Baleias, in the Campos Basin.

The origin of such super-giant light oil petroleum system is related to the existence, in the same pre-salt sequence, a world class source rock system closed associated with thick sequence of shallow water stromatolites and coquinas reservoirs.

The great Lagoa Feia petroleum system is sealed by a thick (2,000m)and widespread salt sequence, extending up to the oceanic-continental boundary. The salt sequence is one of the most important players acting not only as a perfect seal but also in the preservation of the liquid phase of the hydrocarbons and the permoporosity of the pre-salt carbonate reservoirs. Those are mainly related to the salt properties such as sealing, heat conductivity and buffer to prevent compaction for the pre-salt reservoirs.

The 3D petroleum system modeling of specific areas of the Greater Campos Basin showed that the potential hydrocarbon reserves in the Greater Campos Basin are much higher than the one predicted and suggests the deep reservoirs, ranging from Aptian to Barremian as the new frontier for exploration.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas