According to the spokesman for the Nigerian military in the troubled Niger Delta, Lieutenant Colonel Sagir Musa, military escorts assigned to safeguard oil vessels in transit won the early morning shootout in the Delta creeks.
"What happened was that at about 3:00 a.m. today, a ship from Addax company was attacked and on the boat there were eight naval personnel, and they were able to repel the attack," he said. "So that was what happened."
No further details of the attack were available and no one has claimed responsibility.
Militants in the region have stepped up attacks in a bid to cripple the country's petroleum industry.
The Organization of Petroleum Exporting Countries, OPEC, says Nigeria daily oil production has been cut by a fifth because of the violence and it was overtaken as Africa's largest producer by Angola in April.
French oil giant Total says it is reconsidering its operation in Nigeria following the continuous attacks on facilities and kidnapping of workers.