Sample bottle of crude oil are seen in this illustration photo June 1, 2017. Oil prices dropped to six-week lows on Thursday, under pressure from high global inventories and doubts about OPEC’s ability to implement agreed production cuts. Brent crude oil fell 30 cents to $46.70 a barrel, its weakest since May 5 and just above six-month lows, before recovering a little to trade around $46.90 by 0945 GMT. U.S. light crude was down 15 cents at $44.58, also not far off six-month lows. Both crude benchmarks have lost all the gains made at the end of last year after the Organization of the Petroleum Exporting Countries agreed with other big producers to cut output in an effort to prop up prices. OPEC and its allies have promised to restrict output until at least the end of the first quarter of next year to try to drain surplus supply. […]