Brazil has signed an agreement with a consortium of five oil companies to develop a huge offshore field under the so-called production-sharing regime that gives the federal, state and municipal governments a 75 percent stake of the oil extracted.

In October the consortium made up of Brazil's state-owned oil company Petrobras, Shell of the Netherlands,. France's Total and Chinese state companies CNOOC and CNPC won the right to develop the Libra offshore field. It could hold up to 12 billion barrels of oil.

President Dilma Rousseff says Monday's signing establishes "the basis for a more just and less unequal nation and for a period of prosperity that will benefit Brazil for many decades."