While the Asian country was able to meet its energy requirements by producing 4 million barrels per day (mb/d) from domestic oil fields twenty-five years ago, last year the ratio of foreign oil dependency reached 70 percent. This high level of reliance is a reason for concern for the Central Government in Beijing as potential supply disruptions create a security risk. Therefore, the Chinese government has been pushing its state-controlled energy companies to increase production from domestic oil fields to reduce dependence. China's 'big three' Sinopec, Cnooc, and PetroChina have responded to the government's requests and significantly increased spending with mixed results until now. China's advantage The Central Government in Beijing has a controlling stake in the country's three biggest energy companies. PetroChina is the largest company of the three by volume of oil and gas production.