Brazilian oil giant Petrobras has started drilling a fresh well in the Campos basin in an attempt to unlock pre-salt riches and open a new exploration frontier in the ultra-deepwater section of the prolific play.

Petrobras and project partner ExxonMobil late last week started drilling the Urissane wildcat in Block C-M-411 in 2953 metres of water with the Seadrill drillship West Tellus.

Upstream reported in July that the partners were lining up drilling of the well.

The campaign is expected to last up to three months and will target hydrocarbons deposits at a final depth of over 6600 metres.