total oil production (899,000 bbl/d (142,900 m 3 /d) in 1997) from more than eighty oil fields. The joint venture is composed of NNPC (55%),  Shell (30%),  TotalFinaElf  (10%) and  Agip  (5%) and operates largely onshore on dry land or in the  mangrove swamp  in the  Niger Delta . "The company