U.S. crude oil edged up on Friday, posting a second straight weekly gain despite the European debt chaos. Light, sweet crude for December delivery rose 19 cents, or 0.20 percent to settle at 94.26 dollars a barrel on the New York Mercantile Exchange, registering a weekly increase of 94 cents. In London, Brent crude for December delivery also gained and last traded around 112 dollars a barrel after volatile trading.