New York's main contract, West Texas Intermediate for delivery in October, rose 15 cents to USD 105.18 in mid-morning trade, and Brent North Sea crude for October added 41 cents to USD 110.31.
Investors were cheered by figures pointing to a pick-up in the global economy.
A preliminary purchasing managers index (PMI) of manufacturing activity in the eurozone yesterday hit a 26-month high, while a reading in the United States also showed improvement. Earlier in the day HSBC said its PMI for China had also shown growth for the first time in four months.
Chua added that the eurozone data underscored "a nascent recovery" in the 17-nation bloc.
Data this month showed the eurozone economy grew 0.3 per cent in the April-June quarter compared with the previous three months, breaking a record 18-month recession.
Dealers are also closely monitoring an oil supply problem in Libya, analysts said, after Libya's National Oil Company (NOC) yesterday announced a resumption of exports from the Brega terminal in the east.