The well is being drilled in PSC A, about 110km southwest of Nouakchott, the Mauritanian capital, and 42km south of the Chinguetti Oil Field in a water depth of 320m. The planned total depth of the well is 3,330m.

The well is targeting Lower Miocene canyon fill sands of about the same age as the Chinguetti and Tiof oil discoveries in PSC B, said Roc CEO John Doran.

"The high risk Sotto-1 well marks the start of something that has become almost a seasonal event over the past few years for Roc – participating in an exploration drilling program offshore Mauritania,” Doran said.

“This year's exploration drilling program should not be viewed any differently to its predecessors – it's another important step in our understanding of this newly emergent hydrocarbon province which will probably provide a mix of results typical of such frontier drilling programs."

Interests in PSC A and Sotto-1 are: Woodside (operator) 53.846%, Hardman 24.3%, BG Group 13.084%, Fusion/Premier 4.615% and Roc 4.155%.

Roc and Hardman are also participating in the Dana Petroleum-operated PSC 1, as well as the Woodside-operated PSCs A, B and C6.