Petroleum accumulation characteristics in Campos and Santos Basins, offshore Brazil

The Campos and Santos Basins are rich in petroleum. Both of the 2 basins have experienced 3 phases of tectonic evolution (rift, transition and passive continental margin), depositing 3 corresponding sedimentary mega-sequences (pre-salt continental sequence, salt sequence and post-salt marine sequence), and forming 2 plays (pre-salt play and post-salt play). Due to different tectonic frameworks, salt distribution and pre-salt reservoir development patterns are different in the 2 basins. Combining with different post-salt reservoir distribution, obvious difference exists in petroleum distribution between the 2 basins. Petroleum in the Santos Basin mainly distributes in pre-salt sequences of the outer basement plateau while petroleum in the Campos Basin accumulates in post-salt reservoirs of the central low uplift. Based on the analyses of tectonic evolution, sedimentation characteristics and major controlling factors, the favorable exploration zones for pre-and post-salt reservoirs are defined. The differences of accumulation condition between the 2 basins are discussed. The studies may provide Chinese companies a guide for new business development and executing blocks' exploration activities in the 2 basins.