Oil futures fell Tuesday, amid persistent doubts about whether OPEC’s decision to extend production cuts last week will be enough to alleviate the global supply glut. U.S. crude futures settled down 14 cents, or 0.28%, at $49.66 a barrel on the New York Mercantile Exchange. Brent, the global benchmark, fell 45 cents, or 0.86%, to $51.84 a barrel on ICE Futures Europe. The Organization of the Petroleum Exporting Countries and…