Oil rose above $US68 per barrel in price on Friday on optimism that a turnaround in the global economy would lift demand.
US crude settled up 89 cents at $US68.05 per barrel. Prices are up more than 14% since 14 July.
London Brent crude rose $US1.07 to settle at $US70.32 per barrel.
Crude was below $US33 per barrel in December, after slumping from a record $US147.27 per barrel on 11 July, 2008.