22 February 2012
A gas-fuelled fire, with flames as high as 5m, may burn for months in waters off the Niger Delta in south-east Nigeria, Chevron has told the BBC.
Two workers died after January's explosion at the KS Endeavour exploration rig, owned by the US firm.
Friends of the Earth says this is the world's worst such accident in recent years.
Chevron spokesman Lloyd Avram says, despite the fire, the situation is now under control and no oil is leaking.
Nigeria is the largest oil producer in Africa.