Oil prices rose further on Friday, taking gains in the last 10 days to nine percent, after US government data that showed crude and heating oil stocks falling ahead of winter demand.
Benchmark January Brent crude was US$0.30 up at US$29.60 a barrel in London, the highest price for nearly a month, while US light crude for December delivery firmed US$0.40 to US$32.30 a barrel.
Refined oil product stocks are below comfortable levels in the world's biggest oil consumer ahead of colder northern hemisphere temperatures, while faster-than-expected demand growth and concerns over Middle East supply have bolstered prices.
"Traders are quite nervous about what's happening in the Middle East and if you see weekly data that looks bullish you'd expect that to add short-term impetus to prices," said Geoff Pyne, consultant to Sempra Energy.
The US Energy Information Administration (EIA) said on Thursday that crude stocks fell 800,000 barrels last week, while distillate stocks, including heating oil, fell 1.5 million barrels.
This contrasted with analysts' expectations for distillates stocks to rise by one million barrels, keeping oil markets concerned that any tightening of supply or unusually cold weather would come on top of a thin inventory cushion.
Oil prices have risen around 15 percent since a deal in September by the Organization of the Petroleum Exporting Countries (OPEC) to cut production by 3.5 percent in November. However shipping brokers say heavy tanker loadings from the Middle East suggest OPEC has not implemented the cutback in full.
OPEC could further slash supply at a meeting on December 4, which analysts say it needs to do by the first quarter next year to stop rising output from Russia and Iraq eroding oil's four-year price boom.
Bullish sentiment has also been backed up by increased global oil demand growth, which has been driven by strong buying from China, according to a report on Thursday by the International Energy Agency (IEA).
It revised a forecast for global demand in 2003 to 1.28 million bpd, up 1.7 percent from last year.
"It appears that the IEA has been underestimating both demand growth and the contribution of non-OPEC supply," said Kevin Norrish of Barclays Capital in a market note. "OPEC now looks much more secure in its ability to keep prices where it wants them."