Abstract: A Successful Application of the Petroleum System Concept in the Camamu Basin, Offshore Brazil

M. R. Mello, F. T. T. Goncalves, Netto, A. S. T.

The characterization of a major petroleum system in the Camamu basin, NE Brazil, was undertaken using a multidisciplinary approach involving geochemical, geological, geophysical and microbiostratigraphic research. This approach has greatly enhanced the level of understanding of the petroleum system concept in the area, allowing the identification of a new exploration target.

The hydrocarbons sourced by the lowermost Cretaceous lacustrine fresh to brackish water black shales, started migration during the Early Cretaceous times, continuing up to now in some parts of the basin. The hydrocarbons were accumulated in Lower Cretaceous, Rio de Contas Formation lacustrine sandstone reservoirs, structured during the rifting process, and sealed by deep water lacustrine shales, or trapped in the Dom Joao Stage (Jurassic), Sergi Formation, against the footwall of major regional faults. The geochemical parameters indicate that the Camamu basin is basically oil prone.

Mapping the geographic extent of the petroleum system emphasizes the association of the oil fields with the proposed pod of active source rocks. The integration of these data with a 2D-geochemical modelling allowed the prediction and characterization, in time and space, of the petroleum pathways from source to trap in the area. Two major petroleum systems were selected, as the most attractive, in the Camamu basin: the pre-rift Morro do Barro-Sergi (!) and synrift Morro do Barro-Rio de Contas (!). This approach allowed the identification of a new exploration target, in the latter one, which, after drilling, resulted in a 157 M bbl discovery, and brought a new insight for the hydrocarbon exploration in the basin.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France