Ibrahim Babangida, an ageing former military ruler, and AtikuAbubakar, a former civilian vice-president, have both declared that they will seek the PDP ticket.
But Mr Osuji denies the allegations and says he was targeted because of his connections to the vice-president, AtikuAbubakar, who the local press says is Mr Obasanjo's principal political rival.
In a written deposition to Nigeria's House Committee on petroleum resources, which is investigating the charges, Etete claims to have dined in August 2000 with Vice President AtikuAbubakar who, Etete says, demanded a stake as a condition for not revoking the license.