Sahara won 51% of Tsekelewu equity during the previous Nigerian regime's push earlier this decade to force majors to relinquish control of neglected acreage to Nigerian companies.
African Oil&Gas Development took the other 49%.
Cole said OML-40 is "an old concession with a discovery logged in 1978 and substantial 3D seismic shot in 1984".
He added: "Shell never wanted to give it up.
