Opec risks deal fatigue as maintaining oil curbs get tougher

Brent crude fell 60 cents to settle at $51.81 a barrel, while U.S. West Texas Intermediate crude slipped 61 cents to settle at $50.18 a barrel.

LONDON: The Organisation of Petroleum Exporting Countries (Opec) impressed oil traders this year by making almost all the supply cuts it promised. Keeping output down will only get harder.

Opec and its partners are expected to extend output curbs into early 2018 when they meet next week, in an ongoing bid to clear a global surplus.