US oil giant Exxon and its partners Sinopec and Aramco have started a $3.5 billion program to expand capacity at a major refinery in the south of China.

Exxon, the world’s largest oil producer, has formed a partnership with Sinopec, China’s third largest state owned oil company and Aramco of Saudi Arabia to build the extra capacity at the facility located in the southern city of Quanzhou, Fujian province.

The project will triple the refinery’s output to 85 million barrels of petroleum a year and equip it to process imported Saudi crude, AP reported. Furthermore, the joint venture, which will be 50% owned by Sinopec with Exxon and Aramco holding 25% each, will also develop a petrochemical plant and run 600 service stations through a joint marketing agreement.

The deal provides Chinese oil producer Sinopec with a link to external market, while providing its two associates access to the rapidly expanding Chinese energy sector.