A huge natural gas field has been found a short distance off Rio de Janeiro's coastline, Petrobras, Brazil's state-controlled oil company, says.There is more out there, too.
The company believes the new field, Jupiter, could match the recently discovered Tupi oil field in size.
Tupi is thought to be one of the largest fields discovered in the past 20 years.
But Petrobras officials say further work needs to be done to establish Jupiter's exact dimensions.
The new field is located just 37km (23 miles) from Tupi, some 5,100m (5,600 yards) below the surface of the Atlantic Ocean, around 290km from Rio de Janeiro, Petrobras says.
While not providing any specific details on the size of the new reserve, Petrobras said "its structure could have dimensions similar to Tupi".
Petrobras estimates Tupi contains between five and eight billion barrels of light oil.