HONG KONG (AFX-ASIA) – PetroChina Co Ltd (857.HK) said the total crude reserves at its Xifeng Oilfield in China’s Gansu province stood at 432 million tons over a two-year period ending Dec 2003, but only 108 million tons of the reserves have so far been considered as proven geological reserves. A PetroChina spokesman told AFX-Asia…