HANOI, March 17 (Xinhua) -- Japan's Mitsui Chemical is expected to become the fourth partner of a joint venture to develop Vietnam's second oil refinery in central Thanh Hoa province.

    The Nghi Son oil refinery has been the subject of long negotiations between state-owned Vietnam National Oil and Gas Group (PetroVietnam) and its two existing partners, Japan's Idemitsui and Kuwait's Petroleum International, local newspaper Vietnam Investment Review reported Monday.

    PetroVietnam said last week that it expected a joint venture contract to be signed in early April. The Vietnamese group will hold a 25-percent stake with the three foreign partners dividing up the rest.

    The joint venture is expected to officially receive an investment license by June, and construction will start in 2010. The refinery with annual processing capacity of some 10 million tons is slated for completion within 60 months.

    The project will include the oil refinery, refined and material factories, energy facilities, pipeline and storage systems and an informatics system. In addition to LPG, unleaded gasoline, kerosene, jet fuel, diesel and FO, the refinery is projected to produce bitumen, propylene and BTX as a raw material for the domestic petrochemical industry.

    Crude oil may come from the Su Tu Den (Black Lion) oilfield off Vietnam's southern coast, and imports from the Middle East.

    The Nghi Son refinery and the Dung Quat oil refinery, Vietnam's first refinery under construction in central Quang Ngai province, will contribute 70 percent of the country's demand for petroleum products by the time they are fully operational in 2015.

    PetroVietnam is working on another plan to develop the country's third oil refinery in Long Son Island off the coast of southern Ba Ria Vung Tau province.

    According to PetroVietnam, by 2010 the country's demand would be about 18 million tons of refined products, while Dung Quat refinery being able to refine six million tons of crude oil.

    Therefore, the three refineries must be completed by 2015 to meet the demand of about 20 million tons of products, the newspaper said.