Local people, however, said the pollution had spread and impaired their access and prospects of fishing.
Eni said, Saturday, the spill occurred last week about 10 kilometres (six miles) from the Obama flow station in Bayelsa state.
“We do not yet have information either on the causes or the amount of oil affected,” an Eni spokesman told Reuters.
Oil spills are common in Nigeria, where enforcement of environmental regulations is lax and armed gangs frequently damage pipelines to steal crude.
Local community leaders said the spill came from an Eni pipeline and had spread into creeks and waterways. They complained oil companies had not properly cleaned up previous spills.
“Oil companies operating in the Niger Delta are now using harmful chemicals … which is injurious to both sea foods, living organisms and human beings,” said Nengi James, Chairman of the Oil and Gas Committee of Nembe Kingdom.
Decades of oil production in the delta, where Africa’s second-longest river empties into the Atlantic, have turned parts of it into a wasteland of oily water and dead mangroves. Thousands of barrels are spilled every year.