(Reuters) -Oil prices edged up on Thursday after two sessions of losses, as supply concerns over Libya returned to focus, while a smaller-than-expected draw in U.S. crude inventories sapped demand expectations. Brent crude futures climbed 15 cents, or 0.19%, $78.80 a barrel by 0605 GMT, while U.S. West Texas Intermediate crude futures were up 27 cents, or 0.36%, at $74.79. Worries over disruptions in supplies from Libya, a member of the Organization of the Petroleum Exporting Countries (OPEC), were positive for the market, some analysts said.