The companies include Japan’s JX Nippon, Venezuela’s Petroleos de Venezuela and South Korea’s SK Innovation Company.

The sale proceeds would be used to expand the refinery and increase its production capacity from 130,500 barrels to 200,000 barrels per day.

The expansion project, estimated at $1.5-2bn, is set to be completed within the coming five or six years.

Increasing the refinery’s capacity will help meet between 40 and 45% of the country’s total demand for oil and products, according to Binh Son Refining and Petrochemical Company general director Nguyen Hoang Giang as told to Dow Jones Newswire.

The refinery is currently refining sweet crude oil produced in South East Asia.

Following the completion of the expansion, the refinery will process 50% of Middle East sour crude oil and 50% of sweet crude oil.

The project has been plagued by a series of delays, three times involving the withdrawal of foreign oil companies from the project.