Jul. 8, 2009 (China Knowledge) - Changqing Oilfield, which is the second largest oilfield by yield and is owned by PetroChina Co Ltd<601857><0857><PTR>, recorded an oil and gas output of 15 million tons in the first half of this year, a year-on-year increase of 22.99%, sources reported.
The Changqing Oilfield, which is located in Ordos Basin, Shaanxi Province and has an explorat
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