The deep water oil reserves of PETROBRAS, the Brazilian stateowned oil company, have been growing steadily since 1974, with fields at 100m water depth until nowadays, with fields at 2000m. This has forced the company to use pioneering technology, unconsolidated in the world market and also develop technology inhouse, to produce such deep water fields. This paper shall outline the development plan for some of these fields and present the technologies that made their production feasible.
In 1974, Petrobras had their first oil strike in Campos Basin, offshore Rio de Janeiro state, at around 100m water depth. This depth was beyond current technology for conventional oil production, using steel jackets piled to the sea-bed. A world wide search was then made and two promising but unproven sub-sea technologies were deemed likely to stand the test of reality:
Sub-sea dry Christmas trees (Wellhead cellar);
Wet Christmas trees (WCT).
The wellhead cellar concept was selected for the first field (Garoupa field), where the production from nine wells was gathered through a sub-sea manifold center, also enclosed in a one-atmosphere environment, before being sent to the surface through an articulated tower on which the "P. P. Moraes" process ship was yoked. This scheme was functional, albeit very expensive to built and operate, since all manned interventions inside the wellhead cellars or the manifold center required the descent of a special one-atmosphere diving bell, using a modified Diving Service Vessel. Flexible pipes and control umbilicals were used extensively. First oil from Campos Basin however, came up at the Enchova field (120m water depth), in August 1977. This was the work of a maverick group of Petrobras engineers, who decided to go fast and cheap into Early Production System (EPS) technology, duplicating the pioneering North Sea "Emerald Producer" scheme.