CNOOC Ltd, China's largest offshore oil and gas developer, announced on Tuesday that the company, as part of a consortium comprised of Petrobras, Shell, Total and China National Petroleum Corp, has been awarded a 35-year production sharing contract to develop the Libra pre-salt oil discovery in Brazil’s offshore Santos Basin.

Pre-salt is a geological formation off the coast of Brazil that may hold large amounts of oil.

CNOOC holds 10 percent of the winning consortium, with the operator Petrobras holding 40 percent, Shell 20 percent, Total 20 percent and CNPC 10 percent.

As part of the winning bid, CNOOC will pay 1.5 billion Brazilian Reais ($700 million) as its 10 percent share of the signing bonus, and the winning consortium will conduct a minimum work program no later than the end of 2017.

"The participation of CNOOC in the Libra project not only signifies the milestone of a strategic entry into an ultra-deepwater field for the company, it also aligns with our philosophy of seeking partnerships to expand our global footprint," said Li Fanrong, chief executive officer of CNOOC.

The Libra field in Brazil is one of the largest deepwater oil accumulations in the world.

It is located in the Santos Basin, approximately 170 kilometers off the coast of Rio de Janeiro. The block covers approximately 1,550 square kilometers with water depth of around 2,000 meters.

The Brazilian regulator, Agência Nacional do Petróleo estimates that the recoverable resources of the Libra field is between 8 to 12 billion barrels of oil and a total gross peak oil production could reach 1.4 million barrels a day.