A weaker US currency has also pushed up investor demand for dollar-denominated crude futures, they added.
In early deals, New York's main contract, West Texas Intermediate crude for July delivery, was 85 cents higher at $84.83 a barrel and Brent North Sea crude, also for July, rose by 54 cents to $99.39.
"This morning, prices are edging up and the sentiment now is that oil's oversold the last few days and so some see this current pricing as a buy opportunity," said Victor Shum, an analyst with energy consultancy Purvin and Gertz.
He said another factor supporting buying was the euro's rise against the dollar.
The euro was trading higher at $1.2532 in Asian trade today compared with $1.2494 late yesterday in US trades.
Traders will be watching the outcome of telephone talks among finance ministers from the Group of Seven and other economic powers later in the day.
They are expected to focus on the eurozone crisis and weak European banks.
"Those discussions also take place with some of the non-European members of the G20 who are concerned... With the potential consequences of a crisis in the eurozone," Canadian Finance Minister Jim Flaherty said in a press conference.
"The real concern right now is Europe, the weakness in some of the banks in Europe, the fact they're undercapitalised, the fact the other European countries in the eurozone have not taken sufficient action yet to address those issues of undercapitalisation of the banks and building an adequate firewall," he said.