Binh Son bought the crude cargo in mid-August for delivery in October-November for its 130,000-barrel-per-day Dung Quat refinery, two trade sources and a senior company executive told Reuters on Friday, all of whom declined to be named as they were not authorised to speak to the media.

"This is the first batch of crude oil we have imported from Nigeria for the plant," said the company executive, declining to reveal further details.

"We haven’t decided yet if we will keep importing Nigerian crude in the future."

Binh Son, Vietnam’s first refinery, is stepping up efforts to reduce its dependence on the country’s dwindling domestic crude supply and widen its purchase options.

Vietnam’s crude oil imports for the January-August period more than doubled from a year earlier to 5.57 million tonnes, as its domestic oil output fell 6.9 percent, official data shows.

Last month, Binh Son’s Vice CEO Nguyen Van Hoi said the company would import 2 million to 3 million barrels of U.S. West Texas Intermediate (WTI) crude in the second half of this year for the refinery.

Price levels for West African crude grades like Bonny Light are competitive compared with regional sweet, or low-sulphur, crude grades in the Asian markets, said the two trade sources.

Oil major BP likely sold the cargo to Binh Son, according to other trader sources.