ABSTRACT: Petroleum Geology of Campos Basin, Brazil: A Successful Case History of Deep Water Exploration

Milton Romeu Franke, Horacio Antonio Folly Lugon, Wagner Luiz Beraldo

Campos Basin, the most prolific Brazilian basin, produces almost 400,000 bbl of oil per day and contains 70% of the national reserves. The basin is located on the southeastern coast of Brazil, covering a prospectable area of 100,000 km².

Campos is a passive continental margin basin originated by the breakup of Pangea and the rifting of the South American and African plates in the Early Cretaceous. The basin's sedimentary section encompasses three megasequences: nonmarine, transitional, and marine, ranging in age from Neocomian to Holocene.

Hydrocarbon generation is related to nonmarine organic-rich shales and marls, and hydrocarbon entrapment assumes ascendent migration along fault planes and through salt gaps toward reservoirs ranging in age from Neocomian to Tertiary (mainly turbiditic sandstones).

The first onshore stratigraphic well was drilled based on gravity surveys in 1958. The acquisition of new geophysical data, mainly seismic reflection data, followed after 1968. The first offshore well was drilled in

1971, and in 1974, the first oil field, Garopua, was discovered. Giant hydrocarbon accumulations have been discovered in water depths ranging from 400 to 1800 m since 1984.

As of mid-1989, 35 offshore oil fields have been discovered, 760 million bbl of oil, and 490 bcf of gas have been produced. The basin oil and equivalent gas reserves are estimated in 6.0 billion bbl, 60% of which is located in the deep-water giant oil fields.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990