Statoil has bought a stake in one of Brazil's largest oilfields from national oil company Petrobras for up to $2.85 billion.

This will nearly triple its production off the South American country, the Norwegian firm said today. 

Statoil bought a 25% stake in the Roncador oilfield, Petrobras' third-largest producing field, situated in the Campos basin offshore Brazil. 

The deal consists of an initial payment of $2.35 billion plus "additional contingent payments" of up to $550m, Statoil said. 

After the transaction, Statoil's output off Brazil will increase to 110,000 barrels of oil equivalent (boe) per day from around 40,000 boe per day, it said. 

Petrobras will continue to operate the field and will hold a 75% stake. 

Roncador holds expected remaining recoverable volumes of more than 1 billion barrels of oil equivalent, Statoil said.

"The ambition is to increase the recovery factor by at least 5 percentage points, bringing the total remaining recoverable volumes to more than 1,500 million boe," it said. 

The transaction over Roncador will take effect from January 1. The deal is subject to approval from Brazilian authorities.