Brazil will seek to ensure state-controlled Petrobras gets to explore part of the country’s pre-salt crude reserves, home to the largest oil find in the Americas in 30 years, the energy minister said.

The government wants the rules to prevent Petrobras, from being left out of exploring the region if it fails to win a bid for an exploration block, Energy Minister Edison Lobao told reporters today in Brasilia.

“We don’t want Petrobras to lose out,” Lobao said. “This is not about any privilege.”

Brazil’s pre-salt region houses the Tupi field, the largest oil discovery in the Americas since Mexico’s Cantarell field in 1976, said a Bloomberg report.

The area may hold reserves of 50 to 100 billion barrels, enough to supply all US needs for seven to 13 years.

President Luiz Inacio Lula da Silva’s government plans to send Congress a bill to govern exploration of the pre-salt region off Brazil’s coast in August, Lobao said.

Congress will likely pass the bill by the end of the year, he said.

A congressional probe into allegations by opposition parties that Petrobras evaded 4.4 billion-reais (US$2.3 billion) of taxes and overpaid for pipelines and ships may harm business for the oil producer, Lobao said.

The investigation may take time from executives and hinder foreign financing, he said.

Petrobras boss Jose Sergio Gabrielli told reporters in Salvador, Brazil, on 26 May he’s “at ease” about the probe, and denied any wrongdoing.

Lobao said that Brazil’s pre-salt oil deposits will at least double the country’s proved crude reserves, currently estimated at 20 years.