Italian giant Eni has made a pre-salt gas and condensate discovery on Block D4, off the coast of Gabon.
Eni revealed on Thursday the NFW Nyonie Deep-1 well had hit a 320-metre hydrocarbon bearing section in the pre-salt clastic sequence of Aptian age.
It added that preliminary estimates suggested the new discovery was “significant”, with initial potential in place estimated at 500 million barrels of oil equivalent.
The Nyonie Deep structure covers more than 40 square kilometres, covering both the D3 and D4 blocks which are 100% held by Eni.
The company plans to follow up the well with an appraisal campaign to assess its potential, but in the meantime it will start studies for the potential commercial exploitation of the field.
The well was drilled to a total depth of 4314 metres, in a water depth of 28 metres, about 13 kilometres off the coast of Gabon.
Eni has been carrying out exploration of promising pre-salt plays off West Africa and Nyonie Deep marks its third such discovery in shallow waters recently following the Nene Marine and Litchendjili Marine discoveries in Congo-Brazzaville.
Eni has placed the total estimated potential of the discoveries at a combined 3 billion boe, but says they also carry potential for further improvement.
The Italian's success swiftly follows news of an onshore discoveryin Gabon for French explorer Perenco earlier this month.
Block partner Tullow said on Wednesday that Perenco made an oil and gas discovery at the Igongo-1 well on the Nziembou block, where the French player is operator and Tullow has a 40% stake.
"The well encountered 90 metres of net oil and gas pay and options to bring the discovery quickly onstream, through existing infrastructure, are being worked on with the operator," Tullow said.
"Whilst the current expectation of discovered resource volumes is modest, additional appraisal success could enhance the value this discovery has already added to our West African portfolio."
The discovery is understood to be majority oil with some associated gas.
Perenco is also due to spud the Sputnik-1 wildcat inthe Arowe basin off Gabon in the next few days, targeting a pre-salt carbonate play.
Reports earlier this month suggested ExxonMobil, Petrobras and Marathon Oil were among a host of international players selected for a final round of negotiations over the award of nine deep-water blocks off Gabon.
Spain’s Repsol, Perenco of France and Africa-focused duo Ophir Energy and Impact Oil & Gas make up the seven companies selected by the Gabonese Oil Ministry, Reuters reported.