Brazil’s offshore Libra prospect may contain eight billion barrels of oil, higher than the previous estimate of 5.5 billion barrels, rivalling the nearby Tupi field.

Brazil’s ANP energy director Magda Chambriard said energy consultancy Gaffney, Cline & Associates had estimated the field’s volume at 7.9 billion barrels.

The Libra field will be one of the first to be auctioned after Congress approves a new production-sharing system for the region’s oilfields.

Exploration work in the Libra prospect will be completed within 15-30 days.

Brazil may hold more than 50 billion barrels of oil reserves in its pre-salt region, which runs 800km along the Brazilian coast from Espirito Santo to Santa Catarina states, according to ANP.