The friction had apparently been building up after Lukman completed his term as OPEC president in early 2002 .
After Obasanjo moved control and administration of oil blocks from the Petroleum Resources ministry to the NNPC in June 2002 .
The friction had apparently been building up after Lukman completed his term as OPEC president in early 2002 , and after Obasanjo moved control and administration of oil blocks from the Petroleum Resources ministry to the NNPC in June 2002 .