More supply from hydraulic fracturing and horizontal drilling, and less demand, are contributing to the tumble in West Texas Intermediate crude. “If prices go to $80 or lower, which I think is possible, then we are going to see a reduction in drilling activity,” Ralph Eads, vice chairman and global head of energy investment banking at Jefferies LLC, which advised 38 percent of U.S. WTI declined to as low as $87.39 a barrel today on the New York Mercantile Exchange , heading for the the lowest close since April 17, 2013.