Schlumberger Ltd., the nation’s biggest oil services...

Schlumberger Ltd., the nation’s biggest oil services company, posted a 51% drop in first quarter earnings, attributing it mostly to a general decline in business. Ashland Oil, the nation’s 14th-largest oil company, said its profit for the latest quarter more than doubled. “These results are due in large part to an excellent performance by Ashland’s petroleum refining and marketing operations, despite turbulent conditions in the petroleum industry,” said John Hall, chairman and chief executive.