Oil prices dip down on inventory boost, OPEC scepticism

By Ethan Lou NEW YORK (Reuters) - Oil prices dipped on Thursday, with losses limited as an attack on a Nigerian pipeline cut the country's output even as investors remained sceptical about OPEC's planned production limit and surprised at a big build in U.S. crude inventories. Brent crude was down 20 cents, or 0.4 percent, at $46.66 a barrel by 11:05 a.m. EDT (15:05 GMT). Oil ministers from the Organization of the Petroleum Exporting Countries (OPEC) meets on Nov. 30 in Vienna to agree a producti