Brazil plans changes to oil laws-regulator

RIO DE JANEIRO, Nov 13 (Reuters) - Brazil's oil market regulator said on Tuesday the government plans to change rules on oil and natural gas exploration, seeking to increase returns to public coffers.

The decision to change the so-called Petroleum Law, which was approved in 1997 and opened Brazil's market to foreign oil companies, was made last week after state-controlled Petrobras (PETR4.SA)(PBR.N) said its Tupi field may have recoverable reserves of as much as 8 billion barrels.

"What will be done isn't clear yet. It hasn't been decided. But we won't review the (entire) Petroleum Law, but the regulatory environment," Haroldo Lima, head of the National Petroleum Agency, told a senate committee.

Changes likely will be small, and Brazil probably won't adopt any "output sharing" measures similar to those in Venezuela or Angola, said Jean Paul Prates, at ExPetro consultancy.

"It would be absurd for the country to alter significantly a model that is working, that has allowed the country to reach (oil) self-sufficiency and that has brought more than 50 companies to Brazil," Prates said. (Reporting by Denise Luna, writing by Elzio Barreto, editing by Jeffrey Benkoe)