Investing.com - Oil recovered from early losses to trade higher Monday ahead of the implementation of OPEC's agreement to cut output.
Brent crude added 42 cents, or 0.77% to $54.88, off a 16-month high of $55.31 at 08:00 ET. U.S. crude rose 0.74% to $52.06.
Doubts remain about the extent to which OPEC's decision to cut output by 1.2 million barrels a day to 32.5 million will help reduce the global glut.
Non-OPEC members such as Russia have been invited to reduce production by 600,000 barrels a day.
There are also concerns about compliance with the agreed output cuts, which take effect at the start of 2017.
Baker Hughes data released Friday showed the number of rigs operating in the U.S. rise by three in the latest week to 477.
OPEC cuts could usher in a pick-up in activity by North American shale drillers.
The dollar index edged lower. A weaker dollar underpins demand for oil.