ABSTRACT Campos Basin, the main petroleum province in Brazil has gained considerable interest in the last few years with the discovery of two giant fields Marlim and Albacora. These fields have recoverable reserves in the range of 4 billion barrels of oil and 65 billion cubic meters (2.3 TSCF) of natural gas which more than triple the proved hydrocarbon reserves of the basin. Marlim and Albacora lie however in very deep waters extending from 200 to 2,000 meters (660 – 6,600 ft). Ten years experience of application of floating production systems and subsea completions in Campos Basin in fairly deep waters indicate that this technique can be extended to the depth prevailing in those fields. Albacora is already on stream in its shallower portion. The Marlim development is already under way to produce from 600 to 800 meters (1,970 - 2,620ft) water depth in the first quarter of 1990 through a 50,000 BOPD pilot project. In both cases a production cost in the range of ten dollars a barrel is being achieved. INTRODUCTION Campos Basin, the most prolific Brazilian petroleum basin, lies offshore Rio de Janeiro State, on the southeast region of the country (Fig., Its area covers 110,000 sq. km up to 3,400m water depth. The proved reserves of the basin, at the end of 1988, were 1.9 billion barrels of crude oil and 45 billion cubic meters of gas (1.6 TSCFG). The Campos Basin overall production system comprising presently 14 fixed platforms and 11 floating systems distributed among 22 fields (Fig. 2) accounts for the production of 320,000 BOPD (Dec. 1988), 56.4% of the domestic production, and 6.1 million cubic meters of gas daily (215.4 MMSCFD). This production is exported shorewords through 680 km of oil and gas pipelines. The basin exploration began in 1968 and the first commercial discovery occurred in 1974, the Garoupa Field. Production was initiated in 1977 with the completion of a single well (Enchova - 1) producing through a floating production system. Campos Basin has experienced fifteen years of outstanding exploratory rate of success, acquisition and development of exploration and production related technology and upgrading of operational procedures toward cost effective solutions for producing oil an9 gas from medium to very deep water fields. Since the first oil discovery, 26 oil and 3 gas fields were discovered in the basin, at water depths between 80m (262 ft) and 400m (1,312 ft). The recent discoveries of two giant fields, Albacora (1984) and Marlim (1985), are outstanding results in very deep water exploration in a world scale. These fields, situated in waters 200m (656 ft) to 2,000m (6,560 ft) deep, have jointly 18 billion barrels of oil in place allowing to estimate undeveloped reserves around 4 billion barrels of crude oil and 60 to 65 billion cubic, meters of associated gas (around 2.3 TSCFG). GEOLOGY OF THE GIANT FIELOS The turbidite fan complexes of both Albacora and Marlim fields were identified by seismostratigraphic interpretation and later confirmed through drilling tests.