Investing.com - Oil fell Tuesday on profit-taking as investors turned their attention to the implementation of OPEC's deal to cut output.
U.S. crude fell 66 cents, or 1.27%, to $51.13 at 07:45 ET. Brent crude lost 0.89% to $54.45..
OPEC has agreed to cut output by 1.2 million barrels a day to 32.5 million.
But doubts remain about the extent to which this will make significant inroads into the global glut.
OPEC output in November rose to 34.19 million barrels a day from 33.82 million in October.
Non-OPEC members have been invited to reduce production by 600,000 barrels a day.
OPEC and non-OPEC producers are due to meet this weekend to discuss this.
American Petroleum Institute weekly stockpile data are due out later Tuesday.
These will be followed Wednesday by official Energy Information Administration figures.