OREANDA-NEWS. November 13, 2014. China National United Oil, a unit of the country's biggest energy company, bought a record number of Middle East crude cargoes through a trading platform used to determine benchmark prices for Asia.

The company purchased about 21 million barrels this month through the system run by Platts, a unit of McGraw-Hill. Chinaoil bought more than 40 cargoes of the Dubai, Oman and Upper Zakum grades in the so-called window. A Beijing-based press officer for CNPC, the parent company, wasn't immediately able to comment.

"It's very difficult for the market to know Chinaoil's strategy," said Ehsan Ul-Haq, a senior market consultant at KBC Energy Economics. "Prices have gone down and China is always interested in buying more crude whenever the price is right, but they could also have some other different trading strategy."

Benchmark oil prices tumbled into a bear market this month amid signs of an expanding global supply glut, led by the highest US production in about three decades. China consumed the second-largest amount of crude ever last month and its stockpiles increased to a record.

Some of Chinaoil's cargoes may be used to fill the country's strategic crude reserves, according to JBC Energy, a Vienna-based consultant.

"The big question is what China will do with all of these cargoes," JBC said in a report. "If the Middle Kingdom puts the barrels into strategic storage, something that would be logical given low outright prices, they will disappear entirely from the market and China will still have to buy more crude for its day-to-day needs."