S-Oil operates the Onsan refinery, which is located in Ulsan, South Korea. It is an integrated refinery owned by Saudi Arabian Oil. The refinery, which started operations in 1980, has an NCI of 9.8.

Key processes of the refinery

Crude Distillation Unit (mbd): 580
Condensate Splitter (mbd): 89
Vacuum Distillation (mbd): 135
Catalytic Cracker (mbd): 149
Hydrocracker (mbd): 125
Hydrotreater (mbd): 332
Alkylation (mbd): 9

The capacity of the refinery is expected to remain the same as 669mbd by 2030.

Maintenance activities at Onsan refinery

The Onsan refinery witnessed thirteen incidents during the period 2015-2020.

About S-Oil

S-Oil Corporation Inc (S-Oil), a subsidiary of Aramco Overseas Company BV is an oil refining and marketing company. It manufactures and sells oil refined oil, petrochemical and lube products. The company also imports and exports crude oil and refined products. It owns and operates an integrated refining lubricants and aromatic-type petrochemicals complex in Ulsan. The company’s major products include diesel, gasoline, kerosene, engine oil, bunker-C oils, lubricants, naphtha, paraffin oil, asphalt, benzene, xylene and toluene. It markets products in the domestic market through a distribution and marketing network that includes product distribution terminals, and branded retail service stations. The company operates as a subsidiary of Aramco Overseas Co BV. S-Oil is headquartered in Seoul, South Korea.


Information on the refinery is sourced from GlobalData’s refinery database that provides detailed information on all active and upcoming, crude oil refineries and heavy oil upgraders globally. Not all companies mentioned in the article may be currently existing due to their merger or acquisition or business closure.