* Saudi to double refining output at home, abroad by 2015
* Building 2 plants at home; total capacity of 800,000 bpd
* To expand gas production, processing to 4.5 bln cf by 2014 (Adds details, quote)
BEIJING, Nov 13 Saudi Oil Minister Ali al-Naimi said on Friday the Kingdom's overall downstream investment drive will double its refining capacity at home and abroad by 2015.
The world's top oil exporter is building two new mega refineries at home with a combined capacity of 800,000 barrels per day, Naimi said in a speech delivered at Peking University.
These are part of a $100 billion investment plan involving maintaining and boosting oil and gas production capacity and adding refining facilities in and out of Saudi Arabia, he said.
"Having achieved our crude oil production capacity increase to 12.5 mln bpd in June 2009, we are expanding our gas production and processing capacity to 4.5 billion cubic feet by 2014, a 40 percent increase over the current capacity," Naimi said.
Saudi Arabia's demand for gas has been surging to feed its power and industrial sectors in an economic boom fuelled by an oil price rally between 2002 and 2008.
Before Beijing, the oil minister toured the 240,000-bpd Fujian refinery in southeastern Fujian province in which state-run Saudi Aramco has a 25 percent stake in partnership with Sinopec Corp (0386.HK) and Exxon Mobil (XOM.N).
Aramco is now in revived discussions with Sinopec to invest in a second Chinese refinery in the eastern port city of Qingdao, company executives have said.
Saudi Arabia is China's No.1 crude supplier, making up 20 of total imports into the world's second-largest oil consumer. (Reporting by Eadie Chen and Chen Aizhu; Editing by Jacqueline Wong)