Shale Boom Tested as Sub-$90 Oil Threatens U.S. Drillers

"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. OPEC's September output rose to a one-year high of 30.935 million barrels a day.