On London's InterContinental Exchange (ICE), the price of Brent North Sea crude for February delivery fell as low as $US37.49 per barrel.
It was the lowest level since December 13, 2004.
Brent crude later stood at $US38.79 a barrel, down $US1.57 from the close on Tuesday.
Light sweet crude for delivery in February shed $US1.34 to $US37.64 a barrel on the New York Mercantile Exchange (NYMEX).
"Economic concerns continued to be the focus with expectations of further weakness in demand pushing prices lower,'' said analysts at the John Hall Associates energy consultancy.
New York crude for January had plunged last Friday to $US32.40, the lowest reading since February 9, 2004, as investors raced to sell before the contract's expiry.
The price of crude oil has now collapsed by as much as 78 per cent since hitting record highs above $US147per barrel in July, as a sharp global downturn has slashed the world's demand for energy.
Prices clawed back some ground on Wednesday after the US Department of Energy (DoE) said American crude stockpiles fell sharply last week -- suggesting solid demand in the world's biggest energy consumer.
Analysts said that recent US data showing that the world's biggest economy remains mired in a recession was likely to keep crude oil prices under pressure in the immediate term.
"It is just more of the same on the economic front,'' said Jason Feer, Singapore-based vice president with energy market analysts Argus Media.
"There is no sign of any economic recovery that will push up oil demand.''
OPEC, which produces 40 per cent of the world's crude, agreed last week to cut output by 2.2 million barrels per day to shore up the market.
However, prices have continued to fall.
