A Geologic Model of the Carbonate Platform in Deepwater of Campos Basin, Brazil, Constrained by the Jabuti Oilfield
Sant'Anna, Marilia V.1
Machado Jr, Delzio L.1
Viviani, Victor H.1
Metelo, Cynthia Maria S.1
Pontes, Carlos Eduardo S.1
Selbach, Hedio S.1
Bassetto, Marcelo1
Neto, Joao Brasil M.1
Barros, Ana Zélia N.2
Coelho, Dimas F S.2
Santana, Geraldo S.2
1UN-RIO/EXP/ABIG, PETROBRAS, Rio de Janeiro, Brazil.
2E&P-EXP, PETROBRAS, Rio de Janeiro, Brazil.
The first offshore oilfield discovered by Petrobras in Campos Basin was Garoupa, in the Albian carbonate sequence in 1974. After that, the Company maintained an aggressive exploratory approach toward deepwater regions, which resulted in the discovery of Marlim, Albacora, Barracuda and Roncador giant fields in turbidite reservoirs. In 2005 a wildcat well was drilled in the Jabuti structure (Marlim Leste Field, Campos Basin) which discovered a Lower Albian high energy carbonate reservoir, saturated with a 28 API oil. This paper shows a new interpretation of the Albian carbonate platform evolution in deep-water of the central part of Campos Basin, and the contribution of the exploration team to put this play on stream in four years. The methodology applied on this study for the construction of the geologic model was based on principles of seismic stratigraphic interpretation integrated with well data analysis and supported by 3-D structural restoration. Several seismic attributes were tested in order to obtain a good correlation with rock porosity and facies distribution. In the study area, the salt tectonic gravitational gliding started mostly after the deposition of Lower Albian carbonates. The continuity of the halokinetic movement, from Upper Albian to Upper Cretaceous, generated "turtle-back" and raft structures with intense block segmentation, rotation and lateral movement. The 3-D structural restoration revealed the ancient platform geometry, cut by tidal channels, with high energy facies along the rimmed-platform margin. A depositional back-stepped migration of sequences occurred during the drowning phase until the complete flooding of the platform. This study shows the exploratory success of this controlled geologic model tested by the Jabuti Field, where the reservoir thickness varies from 250 to 400m, under 1300m water depth, with good porosity and production.