Oil prices were mixed in thin Asian trade today as investors focused on a fall in US crude inventories, indicating robust demand in the world's top consumer. New York's main contract, West Texas Intermediate, WTI for February delivery, was down ten cents at 100.22 US Dollars in mid-morning trade while Brent North Sea crude for Februarygained 18 cents to 112.36 Dollars.The US Department of Energy on Friday reported that crude inventories for the week to December 20 fell by 4.7 million barrels, more than the 2.2 million expected by analysts in a Wall Street Journal survey.