Equinor and its partners have decided to invest about $9 billion to develop the BM-C-33 gas and condensate discovery off Brazil, the Norwegian company said.
The field which is estimated to hold more than one billion barrels of recoverable oil equivalent is expected to start production in 2028.
"Gas exported from the project could represent 15% of the total Brazilian gas demand at start-up," Equinor said in a statement.
"Its development will also contribute to energy security and economic development, enabling a lot of new job opportunities locally," it added.
Gas from the offshore field will be directly injected into the national gas grid via a 200-km (124-mile) pipeline landing at the city of Macae in the state of Rio de Janeiro.
Oil liquids are planned to be offloaded by shuttle tankers.
Equinor has a 35% stake in the project, while Repsol Sinopec holds 35% and Petrobras the remaining 30%.
