Opposition politicians attacked the new model say that it would “drive away large international companies”. Nevertheless, the reserves - estimated to be between eight and 12 billion barrels of oil - in the Libra field were sold to a consortium made up of some of the most important oil companies in the world: the Anglo Dutch company Shell, and the French company Total with 20% each, and the Chinese companies CNPC and CNOOC, with 10% each.

Private sector companies participate in the shared production model, but without interfering with national sovereignty. The production sharing system combines economic, geopolitical and social factors - and rejects the “privatist” model used for decades. The companies that prevail in the auctions have the right to explore the pre-salt, but according to the model used, the majority of the resources are held by the Federal Government.

Another fundamental factor in the profit-sharing model: the operation is always done by Petrobras. Other companies may join with Petrobras in the exploration of a given block, but only Petrobras can carry out the operation. The company always has a minimum of 30% in each block, and may increase its share as the bidding process is defined (in the case of Libra it is 40%).

All told, according to the calculations made by the federal government, Brazil (at the federal state and local level) would get to keep 75% of the total wealth created by the Libra field. If we add the share of Petrobras in the remaining 25%, Brazil retains 85% of the wealth.

•  one trillion reais for the future of Brazil and Brazilians