The Nembe Creek Trunk pipeline runs from an oil terminal in Bonny to the state of Bayelsa with capacity of 150,000 barrels per day. The explosion happened on Friday.
"We have not been officially briefed on the incident, but it occurred," Bayelsa State Police spokesman Asinim Butswat told AFP.
"No lives were lost as a result of the explosion and we can't confirm if it was an attack by militants or an equipment failure unless the people managing the facility go there" to determine the cause, he said.
OPEC member Nigeria is Africa's biggest producer of crude oil.
Ndiana-Abasi Mathew, a public relations official for Aiteo, the company that manages the pipeline, confirmed the incident in a text message on Saturday.
"There is no official statement at the moment but I can gladly inform you that the fire has been contained and no lives were lost," Mathew said.
Oyinkro Jasper, a local chief from Kalablomi, one of the affected communities, said the blast forced hundreds of residents to flee as it caused "a huge inferno" along the pipeline, which ran through six communities.
Nigerian pipelines are prone to accidents and are sometimes pierced by people who refine the oil themselves to sell on the informal market.
The explosion could also be the result of a criminal act after the re-election of Nigerian President Muhammadu Buhari.
During his first mandate, a group called The Niger Delta Avengers (NDA) had claimed several attacks on oil infrastructure.
In February, the NDA warned that "strike teams are active and gallantly waiting to receive instructions from the high command to cripple the Nigerian economy again" if Buhari won the election.