Saudi Aramco completed last year the largest investment program in its history costing SR375 billion which enabled it to maintain a steady production of oil at the rate of 12 million barrels per day and also enabled it to expand its refining capacity and to establish more petrochemical plants. Saudi Arabia's oil production is currently 12.5 million bpd consisting 15 percent of the world's oil demand. But the company said that it only produced 7.9 million bpd last year with Arab Light comprising 83 percent of it. Aramco noted that the world demand for oil fell during the past two years at a time when it was about to complete its capital investment program. “This caused a surplus of four million barrels in the company's production,” the report said. The company admitted that the surplus was very costly but said it would maintain it in order to supply the international market in case of need. It said a major achievement it made last year was its partnership with the Japanese solar-energy company Showa Shell to produce solar units. “If the solar experimental project proves its success, we will establish a special company for the project in 2012 which will construct factories to produce solar units in the Middle East, Southeast Asia, Africa and Latin America,” Aramco said. It said it was able to raise its storage of oil and natural gas last year thanks to the re-evaluation of its engineering and geological study in addition to promoting the drilling and exploring methods. The company's reserves of crude increased to 260 billion barrels at the end of last year and its reserves of natural gas amounted to 275.2 billion cubic feet. Aramco also said it was planning to increase its production and processing of natural gas by 40 percent during the next four years to 4.5 billion cubic feet in 2014. It added that the natural gas processing plant in the Al Khorasaniyah field, which will produce 500,000 barrels daily, will start operations in June. The plant can process up to a billion cubic feet of sour natural gas daily from the oilfields of Abu Hadriyah, Al Fadli and Al Khurasaniyah with a daily production capacity of 560 million cubic feet. The plant has two units to process liquid natural gas. It will also produce 280,000 barrels of natural gas liquids.