Oil prices edged up in early trading on Monday as the peak demand US summer driving season officially kicks off just as its crude production falls to its lowest level since September 2014.
US West Texas Intermediate (WTI) crude futures were trading at $49.44 per barrel at 0108 GMT, up 11 cents from their last settlement.
International Brent futures were at $49.36 a barrel, up 4 cents.
In global oil markets, Brent prices have been supported by a series of supply disruptions in Nigeria, where militants have been staging a wave of attacks on oil pipelines, cutting the country's output to more than two decade lows.
Attention will also be on a meeting by the Organization of the Petroleum Exporting Countries (OPEC) in Vienna this week, although most analysts do not expect any decisions that would lead to changes in production