Three months ago, the head of Schlumberger Ltd. thought the industry had seen the worst of the U.S. oil market collapse. Now he’s not so sure. Chief Executive Officer Paal Kibsgaard said in July that a recovery might begin by the end of the year. Now he says it could be delayed. Kibsgaard’s comments came in a statement Thursday as Schlumberger reported a 49 percent drop in third-quarter profit. The market is “increasingly challenging with activity expected to be reduced further, ” Kibsgaard said. The world’s largest oilfield services provider reported that profit fell to $989 million, or 78 cents a share, from $1.95 billion in the year-ago quarter. The earnings beat by 1 cent the average of 37 analysts’ estimates compiled by Bloomberg. Even if demand catches up to supply, business will probably continue to decline, Kibsgaard said, as a “lack of available cash flow exhausts capital spending […]