The US crude production added 17,000 to 9.219 million barrels a day last week, said the US Energy Information Agency (EIA) in its weekly report on Wednesday.
There are no signs that the US shale oil producers started to cut production in face of the plunging prices, adding to investors' worries, reports Xinhua.
Due to the US shale oil revolution, American oil production has almost doubled in the past six years.
Inventories at Cushing, Oklahoma, the delivery point for the US contract added 0.9 million barrels to 63.9 million barrels, according to the report.
The West Texas Intermediate for February delivery moved down $2 to settle at $33.97 a barrel on the New York Mercantile Exchange, the lowest close since December 2008.
Brent crude for February delivery decreased $2.19 to close at $34.23 a barrel on the London ICE Futures Exchange, the lowest close since June 2004.