Offshore Brazil 2005
Regional update and future exploration
Abstract
Offshore geophysical data acquisition and offshore drilling have had an
impact on every aspect of the Brazilian offshore petroleum industry since
1999.Seismic programs, massive non-exclusive, spec 2D and 3D data acquisition
programs were conducted offshore the Brazilian coast at record pace in the last
six years and were followed by diverse deep-water drilling programs. The new
geophysical data libraries offshore Brazil brought modern technological era to
seismic interpretation, prospect evaluation, reservoir characterization and
reservoir geo-steering during deepwater development drilling.
The main
producing basins offshore Brazil are situated in the east coast. Modern seismic
interpretation has mapped, through high resolution imaging, the stratigraphy of
hydrocarbon producing turbidite reservoirs, has posted correct geometries of
salt structures and, beneath the salt, has uncovered the structures of the
underlying syn-rift sequences that encompasses most oil bearing source rocks.
Offshore, in the eastern and northern coasts of Brazil the seismic data
acquisition targets the mapping of new reservoirs in deep water and their
relationship with rift sequences source rocks.
Seismic resolution of whole
lithologies offshore Brazil has improved substantially with the new
technologies employed in data acquisition, data processing and data
interpretation. Pre-stack time migrations with higher order NMO are now
routinely performed whereas selected regional lines have been pre-stack depth
migration processed. Regional 2D and 3D surveys acquired with long cables and
large foot-print have provided new data libraries along the whole continental
margin off Brazil, this modern portfolio of regional surveys 2D and 3D are
larger in size to all historical data.
The results of regionally interpreted
seismic lines and regional mapping of the outer shelf, slope and deepwater
provinces of Santos, Campos and Espírito Santo basins are presented
herein. The deepwater turbidite plays along the continental slope are
interpreted from the modern data that allows for precise resolution image of
the syn-rift source rocks, salt architecture, migration paths through faulting
and salt windows, reservoir characterization and regional seal mapping. Future
offshore exploration hence will continue aiming at better seismic resolution of
the deepwater prospects and into the ultra deepwater plays of the salt wall
mini-basins, the last frontier region of the continental crust petroleum
province.