Rigs belonging to PetroChina pump oil near the banks of a snow-covered lake in Daqing in northeastern China's Heilongjiang province. Exxon Mobil is pumping less oil than PetroChina, a company formed just 13 years ago by the Chinese government to better compete for the world's oil and natural gas. (Associated Press)

Rigs belonging to PetroChina pump oil near the banks of a snow-covered lake in Daqing in northeastern China's Heilongjiang province. Exxon Mobil is pumping less oil than PetroChina, a company formed just 13 years ago by the Chinese government to better compete for the world's oil and natural gas. (Associated Press)