PetroChina will open nine exploration blocks in the Xinjiang region to foreign investors to search for oil and gas, Reuters reports.   PetroChina has earmarked 110,000 square kilometres in the southwest, central and eastern parts of the Tarim Basin for cooperative exploration that have already triggered interests of foreign firms, the report added.   The Tarim basin, in northwest China's Xinjiang Uighur Autonomous Region, is pumping 200,000 bpd of oil and gas equivalent after 16 years of work, which is about 5.5 percent of China's total crude output, according to the industry website.   China, the world's second-largest oil consumer, has been struggling to boost domestic oil and gas reserves to keep pace with soaring energy demand. The country now imports more than 40 percent its crude oil needs, Reuters wrote.