Brazilian state-run energy giant Petroleo Brasileiro (PBR) confirmed Wednesday its participation in the Tiber-1 discovery in the Gulf of Mexico.

Preliminary evaluation of Tiber-1 drilling showed indications of a large-scale oil discovery, Petrobras said. The well reached a total depth of 10,685 meters, making it the deepest well ever drilled in the oil industry, the company added.

Announcement of the discovery boosted Petrobras' locally traded shares throughout trading Wednesday. Petrobras' preferred shares rose 1.9% to 32.21 ($16.99) as of 1625 GMT. The shares outpaced the broader market as measured by the Ibovespa stocks index, which declined 0.3%.

Petrobras' U.S. unit, Petrobras America, holds a 20% stake in the discovery. BP PLC (BP) is operator with a 62% stake, while ConocoPhillips (COP) has 18%.

The discovery "consolidates Petrobras' position in deepwater and ultra-deepwater in the Gulf of Mexico's new lower tertiary frontier, benefiting from the company's ample experience and technological dominion developed from its operations in deepwater and ultra-deepwater in Brazil," Petrobras said in the statement.

-By Jeff Fick, Dow Jones Newswires; 55-21-2586-6085; jeff.fick@dowjones.com