Brent North Sea crude for delivery in November struck USD 82.72 a barrel -- the lowest level for since November 23, 2010 -- in earlier Asian trade. The contract later stood at USD 83.34, down 44 cents from yesterday.
US benchmark West Texas Intermediate (WTI) oil for November meanwhile shed USD 1.45 to USD 80.33 per barrel.
"Crude oil prices extended sharp declines ... As investors remained cautious awaiting key oil fundamentals data from the weekly US oil inventories report," said Sucden analyst Myrto Sokou.
Crude futures had also fallen heavily again yesterday on rising fears that slowing economic growth will hit petroleum demand, and spark an even bigger supply glut.
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"Oil fundamentals continue to remain bearish following adequate oil supplies in the US and Asia and serious lack of oil demand worldwide," added Sokou.
"In addition, the recent US macroeconomic data has been very disappointing adding further pressure to an already bearish market."
"This week, global economic concerns worsened, with economic data indicating slowing growth in both China and the US, the world's two largest oil consumers," said analyst Dorian Lucas at British-based energy consultancy Inenco.
Both oil contracts have tumbled by around a quarter in value since hitting 2014 highs in June.
Adding to the pain is a supply glut caused by strong US shale production and a return of Libyan oil on to the market after facilities that were closed due to civil unrest resumed operations.