Oil prices slipped on Thursday, as support from a weaker dollar was offset by US crude inventories near record high levels that again raised concerns whether the Organisation of the Petroleum Exporting Countries (Opec)-led output cuts were starting to drain a global glut. The Opec and some non-OPEC producers cut production from January 1 to reduce record stocks of crude. But an oil price rally after the deal has been hobbled by data showing persistently rising US stockpiles. Latest data from market intelligence firm Genscape showed a build of more than 2 million barrels in the week to March 14 at the Cushing, Oklahoma delivery point for US crude futures, traders said. Data on Wednesday showing a modest slide in crude stockpiles in the United States, the world’s biggest oil consumer, had helped lift oil prices after a week-long rout spurred by record US inventories pushed them to three-month lows. The US Energy Information Administration said on Wednesday that crude inventories fell last week, the first decline after nine weeks of increases, but only by a dip of 237,000 barrels from a record high. It also reported Cushing stocks jumped 2.1 million barrels in the week to March 10. Brent crude ended the session 7 cents lower at $51.74 a barrel, recovering from Tuesday’s drop to $50.25, its lowest since November 30 when the Opec announced its supply accord. The price is still nearly $7 below January’s post-deal peak of $58.37.