Vietnam's sole refinery operator Binh Son Refining (BSR) plans to sell 4 percent of its shares in an initial public offering in November and to sell another 49 percent of its shares to strategic investors next year, its chairman said on Thursday.

BSR, which runs the Dung Quat oil refinery, Vietnam's only operating refinery, would offer shares at 14,600 dong each in its IPO on November 7, BSR chairman Nguyen Hoai Giang said.

The company expects to raise 1.9 trillion dong ($83.6 million) from selling 4 percent of its shares in the IPO, Giang said, which would value the entire company at around $2.1 billion.

It is uncertain when the company would be listed. In Vietnam, listing and IPO are separate processes.

The refinery operator's IPO is part of Vietnam's wider drive to privatise state-owned enterprises to boost performance. The slow privatisation process has gained more momentum since a new government took office last year.

BSR also plans to sell an additional 49 percent stake to one or more strategic investors next year. Spain's Repsol S.A. and Vietnam National Petroleum Corp, or Petrolimex, are among companies that have expressed interest in BSR's strategic sale, Giang said.

Petrolimex and BSR on Thursday signed an agreement where Petrolimex would prioritise buying Dung Quat's oil products, liquid petroleum gas and petrochemical products and exporting the refined products to Laos and Cambodia, the companies said in a statement.

About 17 investment funds have also expressed interest in BSR's stake sale, Giang added.

The stake sale plan still needs approval from the government, which wholly owns BSR via state oil and gas group PetroVietnam, and Giang expected a decision to be made within the next three weeks.

Dung Quat refinery's full-year production this year is expected to reach 6.1 million tonnes, equivalent to about 122,000 barrels per day (bpd), nearly 20 percent higher than its initial target partly due to a tax cut on sales of gasoline and diesel fuel from the refinery.

The refinery has a total capacity of 6.5 million tonnes per year.