Petroleo Brasileiro, or Petrobras, Brazil’s state-owned oil company, on Thursday said well tests revealed its Tupi field may contain as much as 8bn barrels of oil and natural gas, which would considerably bolster the country’s energy clout.

The estimate, if correct, would raise the country’s reserves by 62 per cent and just about put Tupi on par with Norway’s 8.5bn barrels of proved oil reserves.