Brazil oil regulator ANP named the first 12 companies on Friday that have been approved to participate in an upcoming auction of oil and natural gas exploration areas.

The companies that will take part in the auction, scheduled for Oct. 7, include Portugal's Galp Energia, Petro Rio , Royal Dutch Shell, Angola state oil company Sonangol and Engie, the ANP said.

Petro Rio was previously known as HRT Participacoes SA, while Engie was formerly GDF Suez.