An Overview On Campos Basin

ABSTRACT Exploration activities in Campos Basin offshore Brazil started in 1968 with seismic surveys carried out by PETROBRAS. The first oil discovery was made in 1974, one hundred kilometers offshore in 126 meters water depth. Thirthy oil and gas fields have been discovered so far. The main producing reservoirs are sandstones but production is also obtained from limestones, Early Cretaceous to Miocene in age. Campos Basin production started in August, 1977, through a floating production system with one single well producing 12,000 BOPD. As of December, 1987, the average daily output of the basin was 367,000 BOPD. Campos Basin proved reserves at the end of 1987, using 500 m (1,640 ft) as water depth cut off, reached 1.6 billion barrels of oil and 39.5 billion cubic meters of natural gas (1.4 Tcf). Deep water discoveries as from 1984 are expected to increase the total reserves to 7.0 billion barrels of oil and over 100 billion cubic meters of natural gas (3.5 Tcf). Floating Production Systems with subsea completions are being widely used as the main technique for petroleum recovery from small and medium size fields in Campos Basin. Nineteen of those systems were installed, redeployed or discontinued, arriving to the current configuration of 12 systems and more than 100 subsea completions, five of which in waters deeper than 380 meters. Future plans comprise the development by steps of the giant Albacora and Marlim fields, with recoverable oil reserves of at least 1.1 and 3.6 billion barrels, respectively, using floating production systems and subsea completions between 250 to 800 meters water depth. INTRODUCTION Located off the coastline of Rio de Janeiro State, (Fig. 1), Campos Basin is the Brazilian principal source of petroleum accounting for 60% of the domestic crude oil output of 610,000 barrels per day. Most of the Campos fields now producing are located in water depths shallower than 200 meters (656 ft). The proved reserves of the basin, at the end of 1987, were 1.6 billion barrels of crude oil and 39.5 billion cubic meters of natural gas(1.4 Tcf). The basin scenario has been changing as from November, 1984 when the first deep water field, the giant Albacora, with over one billion barrels of recoverable oil, was discovered. In February, 1985, a second deep water giant, the Marlim Field, confirmed the huge hydrocarbon potential of the basin adding more than 3.5 billion barrels to the recoverable oil estimates. Marlim Field is still under delimitation, particularly its southern extension. The major challenge facing PETROBRÁS, is developing technology required to produce oil from those deep water giant fields as part of the all-out effort to diminish the present dependence of Brazil to foreign sources of petroleum supply.