The China National Petroleum Co. said 2012 production from the largest oil field in the country topped 40 million tons of crude for the 10th straight year.

CNPC said production from the Daqing oil field in northeastern China reached 40 million tons for 2012, the country's official Xinhua news agency reports. The report adds that production had passed by 50 million-ton mark previously, though output had since declined "due to harder operations in oil exploitation."

Last year, the field yielded 116.5 billion cubic feet of natural gas.

CNPC said the field was discovered in 1959. By 1976, annual crude oil production passed 50 million tons and remained at that rate for 27 years. A production rate of 40 million tons is expected through 2015.

China in 2011 consumed 450 million tons of crude oil and used 250 million tons worth of imports to satisfy that demand.