Brent crude oil fell more than a dollar to a new five-year low today as producers forecast lower demand for their oil next year.
In a monthly report, the Organisation of the Petroleum Exporting Countries (OPEC) forecast demand for the group's oil will drop to 28.92 million barrels a day in 2015, down 280,000 from its previous expectation.
The price of the North Sea oil benchmark has fallen more than 40% since June as new supplies of high-quality crude from North America have fed a glut in many parts of the world.
Brent futures for January fell to $65.24 a barrel, their lowest since September 2009, before recovering slightly to trade around $65.39 this afternoon.
US crude was down $1.69 at $62.13, having fallen $1.85 to $61.97 in early New York trading, its lowest since July 2009.
Data from the American Petroleum Institute (API) yesterday showed US crude oil inventories rose 4.4 million barrels last week to 377.4 million barrels. Analysts had forecast a drop of 2.2 million barrels.
US petrol and distillate stocks also showed big builds, the API said.
OPEC members are divided on how to respond to the global surplus and falling prices. The cartel may still hold an emergency meeting before its June gathering, Algeria's energy minister said earlier this week.
Italian oil and energy group Eni said OPEC may cut output in the spring and that oil prices will remain between $66 and $75 a barrel next year.
Top oil producer Saudi Arabia blocked production cuts at OPEC's meeting in November and has taken steps to shore up its market share.