A spokesman for Afghanistan's Mining Ministry, Jawad Omer, has told RFE/RL that the Canadian company Terraseis has located a large oil field in the northwestern part of the country.
"This area is situated between the Khan Charbagh and Aqeena border districts, where technical research has been conducted," Omer said.
The site is in Faryab Province, near the border with Turkmenistan. Omer said more exploration would be done to get an accurate assessment of the size of the oil field.
Mining Minister Wahidullah Shahrani called it a "historic" day for his country, "that for the first time the process of commercial production of crude oil has started in Afghanistan."
The CNPC is initially expected to produce nearly 2,000 barrels of oil per day at the Amu Darya site in Sar-e Pol Province but plans for a drastic increase in volume as more wells are opened.
The CNPC signed contracts to develop oil and natural-gas fields in northern Afghanistan in December 2011.
The CNPC contract also calls for construction of Afghanistan's first oil refinery.
China is already developing a gas field across the border in Turkmenistan and has provided loans to the Turkmen government to develop the massive South Yolotan-Osman gas field in southern Turkmenistan.
The South Yolotan-Osman field is one of the world's largest, with conservative estimates claiming there are some 4 trillion cubic meters of gas there, and some other estimates saying the field has more than 14 trillion cubic meters.
There is speculation that the field extends across the border into Afghanistan.
At a June summit of the Shanghai Cooperation Organization in Beijing, Afghan President Hamid Karzai also lent his support to plans for a gas pipeline from Turkmenistan through northern Afghanistan and Tajikistan to China.
Afghan gas could be included in the pipeline.
The news of the oil discovery in Faryab and start of production in Sar-e Pol has Afghan officials talking about energy self-sufficiency for the country.
Northwest Afghanistan is believed to hold vast deposits of oil and natural gas.