The well, located off the Brazilian coast northeast of Rio de Janeiro, could start producing as early as next year and would likely supply around 1.7 million cubic meters per day once its brought online, Chief Executive Magda Chambriard told reporters at an event.
The announcement marks the first big move by the state-run producer to provide Latin America's biggest economy with more natural gas.
Lowering the price of the key energy input for both consumers and industry has been a priority during President Luiz Inacio Lula da Silva's government.
Chambriard, who took office earlier this year, noted that the firm has scanned the area in search for gas in the near term, citing the reopening of the Roncador well as an example of its efforts.
The executive also said Petrobras was set to lower jet fuel prices by nearly 10% starting in October, and that the company will also seek reduce motor fuel prices for drivers but without setting a specific timeline.
In a release sent just after Chambriard's statement, Petrobras announced a 9% cut to jet fuel prices for next month.
"Whenever we see that it's possible to reduce prices, we will do that," said Chambriard.
She noted that Petrobras will likely release its next five-year investment plan in November.
