Oil prices fell again on Tuesday.
Light sweet crude for December dropped 56 cents to close at $US54.39 on the New York Mercantile Exchange.
In post-market trade, the New York contract slid to $US53.96.
In London, Brent North Sea crude for delivery in January settled 47 cents lower at $US51.84 a barrel.
The Centre for Global Energy Studies predicts global demand will contract this year for the first time in 25 years amid a global economic slowdown.
It says a decision by members of the Organization of the Petroleum Exporting Countries last month to reduce production by 1.5 million barrels per day has so far failed to halt the slide in prices.
OPEC will next meet on 29 November in Cairo, followed by a summit in Oran, Algeria, two weeks later.
Oil prices previously reached a record $US147.27/b on 11 July.
