The main focus is the String of Pearls area along the eastern Mississippi Canyon and the west and south-west De Soto Canyon areas, which include the ­Appomattox and Vicksburg discoveries.

Shell and its partner Nexen have indicated that the Appomattox find alone holds at least 250 million barrels of oil equivalent with upside potential.

There are already plans for a floating production semi-submersible there.

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