The Discovery of a Paleogene Carbonate Platform Using 3-D Seismic Geometry, Espirito Santo Basin, Offshore Brazil
Acquisition and interpretation of a PrSTM 3D seismic cube in the Espirito Santo basin, Brazil allowed for the interpretation of a Tertiary carbonate platform and the definition of a new offshore play. Initial exploration efforts in the exploration area focused on exploring for Late Cretaceous and Paleogene turbidites. Improved seismic resolution allowed for the identification of stratal geometries unique to carbonate platforms. There was no well coverage in the block so a regional correlation study was made, based on 2D seismic data to tie the platform to wells containing the same carbonate interval. The study showed a Tertiary platform development with large-scale, prograding, clinoforms with 40o slope angles, raised rim and margin geometry and a flat-lying, back-reef lagoon. Seismic geometry clearly shows the outbuilding of the platform followed by an incipient drowning with an associated back-stepping build up. Carbonate growth continued with a subsequent drop in sea level and the rapid progradation of smaller platforms off, and away from, the buildups with small-scale clinoforms clearly visible on seismic sections and attribute maps. Carbonate growth terminated and the platforms were capped in marine shale. Regional cuttings studies from off-platform intervals indicated the “carbonate factory” was dominated by large benthic foramanifera, bryozoans and red algae. Seismic geometries imply high-energy depositional environments while analogues indicate the potential for favourable reservoir.
New Plays in Rift and Passive Margin Settings
2005 AAPG International Conference and Exhibition (September 11-14, 2005) Technical Program