Shares of Repsol-YPF, Petrobras and BG Group rose sharply on Tuesday after Brazil’s energy regulator said that an oil field in the country to be explored by the three groups could be huge.

Haroldo Lima told reporters that the Carioca oil field “could contain reserves as large as 33bn barrels of oil equivalent” and that the find would be the world’s biggest discovery in the past 30 years.