Shell this week signed production sharing contracts for two blocks off Mauritania, marking the Anglo-Dutch supermajor's entry into the high-potential West African Margin.

Shell will take operatorship of offshore blocks C-10 and C-19, which lie in water depths ranging from 20 metres to 2000 metres.

Previously held by Tullow Oil, the PSC for C-10 covers a newly expanded block drawn to absorb previously designated C-28 and C-29.

Mauritania Oil, Energy & Mining Minister Mohamed Ould Abdel Vetah said Shell's entry “will add value to Mauritania’s exploration activities and help maintain momentum in developing the energy sector”.

The basin holds “great potential” for exploration, said Shell upstream director Andy Brown.

“We look forward to working with the government and people of Mauritania as we bring our expertise and technical capability to help develop the country’s emerging energy sector,” Brown said.

Shell will set up an office in the capital Nouakchott and begin reprocessing and analysing existing seismic data and then acquire fresh survey data.

The company declined to provide an exploration timetable or details of its seismic and drilling commitments, saying only that it was engaged in “a phased exploration programme” and that more information may be forthcoming once the PSCs receive government approval.

Under a memorandum of understanding, Shell will jointly evaluate further exploration opportunities and explore ways to meet domestic energy demand and build indigenous capability across the energy sector.

Shell will take a 90% operating stake in both licences, which cover 23,675 square kilometres, leaving state-owned SMHPM with 10%. Subject to regulatory approval, Shell has also agreed for AIM-listed Chariot Oil & Gas to re-enter C-19 for a 10% to 20% stake, Chariot having earlier withdrawn from the block in 2016.

Shell had exposure to Mauritania in the late 1990s, when the company held a significant stake in Woodside Petroleum.

Woodside farmed in to Hardman Resources acreage, later bringing on stream the under-performing Chinguetti oilfield. Shell’s re-entry will hearten the Mauritania government, which already has BP and Kosmos Energy exploring offshore blocks C-6, C-8, C-12 and C-13 while developing the Greater Tortue gas field, which straddles the maritime border with Senegal.

Having another major active on the play could add weight to Mauritania’s pitch to determine fiscal terms for unitised ventures as it pursues a role in directing regional gas-to-power supplies.