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.