Oil prices fell on Friday, dropping below $US85 a barrel, as high inventories raised concerns about weak demand.
US government data this week showed inventories reached their highest level in almost 10 months, an indication supply is still outpacing demand.
US light sweet crude for delivery in May fell 47 cents to $US84.92 a barrel.
London's Brent North Sea crude for May won 43 cents to $US85.23 per barrel.
Early in the week, oil prices broke above the $US65 to $US85 range in which they have traded since August, to touch an 18-month high of $87.09 on Tuesday.