The Discovery of
a Paleogene Carbonate Platform Using 3-D Seismic
Geometry, Espirito Santo Basin, Offshore Brazil
Campbell, A. Ewan1,
Klaus Fischer1, Matthias Stollenwerk2, Wolfgang H.H.J.
Ludwig1, Christian Derer3, Michael Zechner1 (1)
Wintershall AG, Kassel,
Germany (2) Wintershall Nordkaspische
Explorations- und Produktions GmbH, Moscow, Russia (3)
Wintershall Noordzee B.V,
Den Haag, Netherlands
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 backstepping 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 offplatform
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.
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