US September crude futures rose 83 cents to $82.17 by 12:03 p.m. EDT (1603 GMT) after hitting an intraday high of $82.59. The last time US crude traded above $82 was on May 5. ICE Brent rose $1.60 to $82.42.
North Sea Brent crude oil futures rose above U.S. crude as planned summer maintenance reduced supplies of prompt oil from British and Norwegian oil fields.
"Crude was up on the weak dollar and Brent was higher on maintenance, helping lead the complex higher," said Andrew Lebow, broker at MF Global in New York.
US crude futures have convincingly broken out and above the $70-$80 a barrel trading range this week, which it had been stuck in for most of the past three months. The move higher has prompted some further buying.
Meanwhile, US and European stocks slipped and the dollar fell to multi-month lows against the euro and the yen on Tuesday as disappointing corporate earnings and US economic data added to fears about the global recovery.
Treasuries rallied as investors sought safety, sending yields on the two-year notes to an all-time low, although analysts said a decline in stock prices was expected after a rally on Monday lifted them to a three-month high.
A Wall Street Journal report that the Federal Reserve was considering buying more bonds to prop up the economy further boosted Treasuries prices.
Global stocks measured by the MSCI All-Country World Index still edged up 0.13 percent after closing on Monday at their highest level in nearly three months.
Key US and European stock indexes dipped.
The FTSEurofirst 300 index of top European shares closed down 0.01 percent at 1,070.79 points as banks and miners gave back some of Monday's sharp gains.
The Dow Jones Industrial Average lost 29.52 points, or 0.28 percent, to 10,644.86, while the Standard & Poor's 500 Index dropped 4.43 points, or 0.39 percent, to 1,121.43. The Nasdaq Composite Index fell 9.27 points, or 0.40 percent, to 2,286.09.
The dollar plunged in tandem with short-dated US Treasuries yields due to fears that the U.S. economic recovery was faltering.
The greenback slid against a basket of major currencies, with the US Dollar Index down 0.42 percent. The index fell below its 200-day moving average for the first time since January, which analysts said may signal more dollar selling ahead.
The euro hit a three-month high of $1.3261 against the dollar. It pared gains later, but was still up 0.36 percent at $1.3227.
The dollar also fell below 86 yen, its weakest showing against the Japanese currency since November.
