Brazil's state-owned oil company, Petrobras, says it has discovered what it calls a "giant" oil field off the Atlantic coast of Rio de Janeiro state.

Petrobras says the new oil field, called Papa Terra, contains between 700 million and one billion barrels of heavy crude, at a depth of some 1200 meters.

The company says it expects to start production in the new field by the end of 2011.

Petrobras owns 62.5 percent of the oil field, and its U.S.-based partner Chevron owns the other 37.5 percent.

Brazilian officials expect the nation to be self-sufficient in oil in 2006. Petrobras currently produces more than 1.8 million barrels of crude oil a day.