Oil prices rose on Thursday after the signing of an initial Sino-U.S. trade deal that sets the stage for a surge in Chinese purchases of American energy products, while U.S. crude inventories fell more than expected. Official U.S. data showing a much bigger than expected drop in crude oil inventories, also helped underpin prices, Chauhan said. Trade sources and analysts said China could struggle to meet the target and gains in oil are likely to be limited ahead of more detail on how the commitments will be achieved.That sent Brent to highs above $71 a barrel, before prices touched more than one-month lows in advance of the signing of the U.S.-China deal.