Haroldo Lima, part of a government group debating changes to rules for oil exploration and production, cited such a model, used in Russia, as an option for Brazil.

Addressing congress, Lima promoted the adoption of a production-sharing model for low exploratory risk areas, including potentially huge subsalt reserves encountered in late 2007. He also defended maintaining the present tax and royalty system in areas with higher risk.

Lima, who was criticized by Brazil’s stock market regulator for giving huge reserve estimates for the subsalt oil reserves in 2008, reaffirmed they could reach 50 billion barrels of oil equivalent.

We’ll have a reserve of more or less 60 billion (boe), and with the current 10 (billion boe in proven reserves), this puts Brazil’s among the world’s 10 biggest reserves, Lima told legislators.