Oil prices rose slightly on Tuesday, breaking a six-day series of falling prices, but doubts about the OPEC's ability lowering global oil inventories capped gains.
Brent crude LCOc1 rose 8 cents at $51.68 a barrel, while U.S. crude futures rose 4 cents at $49.27 a barrel.
Brent dropped by 10% since late 2016, despite OPEC's efforts and Russia to cut production by 1.8 million barrels per day in the first half of 2017.
Oil supplies remain near record levels. Schork Group President Stephen Shork said that OPEC's mission has failed miserably in its efforts to balance the oil market.