S-Oil, South Korea's third-largest refiner, plans to spend 1.4 trillion won ($1.2 billion) to expand its 580,000 barrels per day (bpd) Onsan refinery.

'The company has completed its alkylation project to produce eco-friendly products and is pursuing the Onsan refinery expansion project to create a new growth engine for its future,' Saudi Aramco said in a statement on its website.

Expanding the refinery would be completed by 2011, Aramco announced.-Reuters