Shale SlowdownThe biggest slowdown in oil drilling on record is showing signs of reining in the U.S. shale boom.Output is expected to post the slowest growth in more than 4 years in April, the E.I.A. said Monday. Slowdown in output would come at the same time refineries are expected to return from seasonal maintenance and bring relief to the oil market. "You have refineries coming out of maintenance and production cutting back", said Carl Levy head of oil and gas for Frost and Sullivan in Houston. "Everything could come together where all of a sudden , everyone thought there was plenty of supply and there's not." Bloomberg. The refineries in the U.S. that have been hit by a strike may have reached a tentative agreement.