The Northern Brazilian Equatorial Margin, including the Foz do Amazonas, Pará-Maranhão and Barreirinhas basins covers an area of approximately 560,000 km² up to the 3,000 m isobaths.

The basins are directly related to the breakup of the African and American plates during Aptian-Albian times. Recent studies suggest that large oil/gas accumulations must be present in the deep to ultra-deep water realm of the margin.

The Foz do Amazonas Basin has been explored since the 1960´s and up to now only sub commercial gas, condensates and oil accumulations have been found. The presence of active oil and gas in Tertiary and Upper Cretaceous reservoirs is a definitive proof of the existence of multiple active petroleum systems in the basin.

In the Pará-Maranhão Basin, most of the exploration activity has taken place during 70 and 80´s where most of the 34 wells were drilled. Only two wells have been drilled in water depths deeper than 83m (drilled in 1993 and 2011).

Direct evidence of active oil and gas petroleum systems were obtained by the recovery of gas and light oil in several exploration wells. Compositions of the oils confirm the presence of at least three active petroleum systems.

The Barreirinhas Basin covers an area of approximately 50,000 km² of which 20% is onshore. The presence of onshore gas and light oil sub-commercial discoveries proved the presence of active oil & gas petroleum systems in this Basin. Recent studies suggest that Barreirinhas Basin might be a new exploration play for the Equatorial Margin.