PetroChina will open nine exploration blocks covering 110,000 square kilometers within Xinjiang Region's Tarim Basin to foreign investors, unlocking potential resources in the under-explored area and bolstering supply for the 3,800km Xinjiang-Shanghai gas pipeline, China Oil News reported. The cooperation will be in a profit-sharing structure commonly used worldwide, in which foreign firms will foot the exploration bill and output and revenues will be shared after the exploration and development expenses are recovered. The 560,000 sq km Tarim Basin is estimated to have six billion tonnes of provable oil reserves and eight trillion cubic meters of provable gas reserves.