Oil prices breached a six-week peak on Monday above $55 a barrel despite brimming crude stocks in the United States, as early worries of thin winter supply pushed up heating oil to two-month highs. U.S. light sweet crude rose 39 cents to $55.42 a barrel in Asian trade, extending gains of $1.40 in New York on Friday. London's Brent crude was up 13 cents to $54.30 a barrel. "The market certainly continues to focus on a surprise drop in heating oil inventories. Prices are being driven by technical reasons, with plenty of funds activities seen in the last couple of trading sessions," said Daniel Hynes, resources analyst at ANZ Institutional Banking in Melbourne. Heating oil futures jumped 0.90 cents at $1.6085 a gallon and the July contract held at a rare 4.7-cent-a-gallon premium to gasoline at a time of year when more Americans drive during the summer holidays. U.S. stocks of heating oil, used to keep people warm in the wintry months, fell 700,000 barrels in the week ended May 27. "The market is being gripped by fear of a supply disruption due to limited refining capacity," Hynes added.