ABSTRACT: The Marlim and Albacora Giant Fields, Campos Basin, Offshore Brazil

Jairo Marcondes De Souza, Julio Cesar Scarton, Aladino Candido, Carlos Alberto Guedes Cora

The Albacora and Marlim giant fields are located in the province of Campos basin, about 110 km (68 mi) offshore Cape Sao Tome, in water depths ranging from 200 m (656 ft) to 2000 m (6562 ft).

The Albacora field was discovered in September 1984 by the wildcat 1-RJS-297, drilled in 293 m (961 ft) of water. Subsequently, the wildcats 1RJS-305 and 1-RJS-342 extended the field limits to deeper waters. The Albacora field is approximately 235 km² (90 mi²) in area, with an estimated volume of 4.5 billion bbl of oil in place.

The Marlim field was discovered in February 1985 by the wildcat 1-RJS-219A, in a water depth of 853 m (2800 ft). The Marlim field area is about 152 km² (58 mi²), and the latest estimate of oil in place is about 8.2 billion bbl.

The Marlim complex encompasses Marlim field itself and the surrounding proved and potential areas known as East-of-, West-of-, and South-of-Marlim, respectively. The current estimated volume of oil in place in the Marlim complex is close to 13.9 billion bbl, with a total surface of about 350 km² (135 mi²).

Oil production in the Albacora field comes from Lower Cretaceous (Albian) and Tertiary (Eocene, Oligocene, and Miocene) turbidite reservoirs. Oligocene turbidite sandstones are the potential reservoirs in the Marlim field. These deposits are genetically associated with sea level variations and are mainly composed of massive sandstones and, subordinately, of contourites.

Both fields are structurally and stratigraphically controlled accumulations. Hydrocarbons are trapped in anticlines and/or faulted blocks associated with salt tectonics. Stratigraphic contributions result from sandstone bodies pinching out against shales and marls.

The development of these fields has been supported by three-dimensional seismic data. The Albacora field is being gradually put on stream from shallower to deeper waters. This strategy determines the acquisition of new technology necessary to produce oil in areas of increasingly deeper waters. A pilot floating production system to be on stream in 1990 in the Marlim field will provide data to improve deepwater technology and operational reliability.

AAPG Search and Discovery Article #91000©1990 AAPG Conference-Giant Oil and Gas Fields of the Decade 1978-1988 Conference, Stavanger, Norway, September 9-12, 1990