The big enchilada of oilfield services, Schlumberger (NYSE: SLB), resumed its role as the group's earnings season leadoff member on Friday -- a role that had gone to Halliburton (NYSE: HAL) during the past few quarters. The results should nudge Fools toward rapt attention to the group as we move through 2011.

For the quarter, Schlumberger's earnings from continuing operations, excluding items, was $1.16 billion, a 42% year-on-year increase. On a per-share basis, earnings were $0.85, versus $0.67 a year ago. As such, the company easily topped the Street's consensus expectations of $0.77.

Revenue for the quarter was $9.07 billion, up a full 58% from the $5.74 billion in the year-ago quarter. However, the latest quarter included $729 million in revenues from the operations of Smith International, the drilling technologies company that Schlumberger recently acquired.

Schlumberger's larger oilfield services segment increased its pre-tax operating income by 32%, compared with the fourth quarter of 2009. At the smaller WesternGeco segment, which is involved in seismic activities, the operating income fell by 1% year over year, although compared with the third quarter, the operating income grew by a full 183%.

On a geographic basis, CEO Andrew Gould noted that, as a result of the industry's increased attention to liquid-rich plays, along with improved activity in Canada, North America remained strong. Further, the company was able to expand its margins through stronger pricing and restructuring efforts. The company also pointed to the North Sea, West Africa, and several markets in the Middle East and Asia -- along with robust sales of software and other products -- as offsets to continued weakness in Mexico and a "seasonal activity decline in Russia."

But because successful investing involves looking ahead, rather than peering at a rearview mirror, it's important to note that regarding oil, Gould said that, "The consensus forecast for demand in 2011 shows a further healthy increase (from 2010). Oil prices have moved into a range that will encourage increased investment, particularly in exploration ..." He also predicted a profit for the company in Iraq, where it is working for a number of the major companies, including BP (NYSE: BP) as well as ExxonMobil (NYSE: XOM).

As to natural gas, however, he was less sanguine. As he said, "Increases in supply of both unconventional gas in the United States and liquefied natural gas around the world will limit the progress of prices."

So, assuming that Halliburton, Baker Hughes (NYSE: BHI), and Weatherford (NYSE: WFT) follow in Schlumberger's footsteps when they report on Monday and Tuesday, prospects appear bright for oilfield services. For my money, given its geographic spread and its technological strength, Fools with a taste for energy would be wise to put Schlumberger in an especially prominent position on their watch lists.

The Fool owns shares of ExxonMobil. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Fool contributor David Lee Smith doesn't own shares in any of the companies included in this article. The Motley Fool has a disclosure policy.