RIASSUNTO
Abstract
Market oriented reforms of the Brazilian petroleum industry have givenimpetus to an extraordinary renewal of the offshore geophysical dataacquisition and will impact all aspects of the Brazilian offshore petroleumindustry for years to come. Massive non-exclusive 2D and 3D seismic dataacquisition programs are presently being conducted offshore the easternBrazilian coast, soon to be followed by diverse deep-water drilling programs.The increased offshore operations have also caused a higher environmentalawareness and all activities are monitored for possible effects over theecological equilibrium of the offshore environment.
This paper reviews the new outlook of geophysical data acquisition offshoreBrazil, its implications for the interpretation of petroleum geology andgeophysics and the future exploration of the continental margin off easternBrazil. It succintly describes the modern efforts in seismic data acquisition,processing and interpretation leading to the high resolution mappingstratigraphy of hydrocarbon producing turbidite reservoirs, the accurateimaging of the salt structures and the structural seismic interpretation of theunderlying synrift sequences that encompasses most oil bearing sourcerocks.
The modern seismic exploration is therefore focused towards the preciseimaging of hydrocarbon plays of the pre-salt and post-salt sequences. Seismicresolution in these have improved substantially with modern technologies nowemployed in data acquisition, data processing and data interpretation.Pre-stack time migrations with higher order NMO are now routinely performedwhereas selected regional lines are pre-stack depth migration processed.Regional 2D and 3D surveys acquired with long cables and large foot-print arethe now the norm along the whole continental margin off Brazil.
Introduction
Although Brazil has the longest north-south coast in the world the petroleumresources of its offshore basins (Fig. 1) are still not fully assessed. For thelast fifty years Petrobras, the national oil company, held over a monopoly ofthe country's oil and gas industry. In 1996 the first step was taken to breakthe monopoly with the formation of the National Petroleum Agency (ANP), to takecontrol of the industry's regulation. When, in 1997, the Petroleum Law waspassed, a programme of market-orientated reforms of the industry was underway.In December 1998, David Zylbersztajn, ANP Director General, announced the firstannual block release, opening the Brazilian market to competition.