By Sonali Paul MELBOURNE (Reuters) – Oil prices fell on Thursday after industry data showed a large unexpected increase in U.S. crude stocks for a second week, heightening concerns of a drop in fuel demand. U.S. West Texas Intermediate (WTI) crude futures declined by 86 cents, or 1.1%, to $78.62 a barrel at 0109 GMT, while Brent crude futures fell 73 cents, or 0.9%, to $84.25 a barrel, extending losses of around 1% from Wednesday. The market weakened on worries about a looming U.S. economic slump after Federal Reserve officials said rates needed to rise beyond 5% to control inflation even afte…