New York's main contract, West Texas Intermediate (WTI) for February delivery, was up 22 cents at USD 98.64 in mid-morning trade while Brent North Sea crude for February rose 17 cents to USD 110.97.
Sanjeev Gupta, head of the Asia-Pacific oil and gas practice at consultancy firm EY, said prices were buoyed by "signs of revival in US economy".
Kelly Teoh, market strategist at IG Markets in Singapore, said investors were looking ahead to the release of US stockpiles data on Friday, with thin Asian trade due to the closure of Japanese financial markets.
The report, usually released on Wednesday, has been postponed due to the New Year's Day holiday. According to analysts polled by Dow Jones Newswires, the average forecast is that crude oil supplies fell 2.2 million barrels last week.
"Everyone's just looking at the inventories... I don't think, in terms of fundamentals, anything has changed which is why the movement is very subdued," Teoh said.
Investors are also monitoring the situation in crude producer Iran after the IRNA news agency on Wednesday said experts from Tehran and world powers have chosen January 20 to begin implementing a deal on Tehran's nuclear programme. Iran and the so-called P5+1 nations - United States, Britain, France, Russia and China plus Germany - have been holding technical talks on implementing a deal reached in November on Iran's controversial nuclear ambitions.
Tehran's crude exports have been halved to 1.2 million barrels per day following crippling international sanctions imposed on it for allegedly covertly pursuing a nuclear weapons capability alongside its civilian programme.