Oil prices fell in Asian trade today after plunging more than five percent overnight. This follows weakening global economy and eurozone debt crisis threatening energy demand.New York's main contract, West Texas Intermediate light, sweet crude for delivery in September, was down 92 cents to 85.71 dollars a barrel in morning trade after plunging 5.30 dollars in US trade yesterday.Brent North Sea crude for September delivery shed 13 cents to 107 dollars 12 cents after falling 5 dollars 98 cents in London trade.