S-Oil Corporation is a petroleum and refinery company, headquartered in Seoul, South Korea. It was established in 1976 under its original name Iran-Korea petroleum company. It produces petroleum, petrochemical, and lubricant products. The company was listed as a Fortune Global 500 company in 2009. S-Oil's Onsan Refinery in Ulsan, South Korea has a capacity of some 650,000 barrels per day in 2016. Wikipedia