Schlumberger says Q1 North America activity weaker than expected

March 18 (Reuters) - Schlumberger Ltd, the world's largest oilfield services company, warned on Monday that North American activity was coming in lower than expected in the first quarter, as fewer rigs were going back to work than it had expected.

Shares of Schlumberger fell 2.5 percent to $77.40 in early trading on the New York Stock Exchange.

In a copy of a speech delivered by Chief Executive Paal Kibsgaard on Monday, Schlumberger said asset utilization had recovered from a holiday slowdown and lower cost of a key hydraulic fracturing ingredient, guar, was providing some relief. But pricing remains the fundamental issue, he added.

"We continue to see negative pricing pressure in many product lines in the first quarter, with active participation from our principal competitors, reinforcing the somewhat unclear outlook for the North America land market at this stage," Kibsgaard said in the speech to the Howard Weil energy conference in New Orleans.

(Reporting by Braden Reddall in San Francisco; Editing by Gerald E. McCormick)