U.S. West Texas Intermediate crude futures for December delivery were down 88 cents, or 1 per cent, to $84.44 a barrel, reversing the previous session's gain.
That was higher than expectations from five analysts polled by Reuters, who on average had expected a build of about 200,000 barrels. Official U.S. stockpile data from the government's Energy Information Administration is due on Wednesday at 1430 GMT.