The largest of the oilfield services contingent reported its second-quarter earnings on Friday, and while the results were hardly impressive -- or surprising -- Schlumberger (NYSE:SLB) remains a company worth Foolish attention.

For the quarter, the company reported net income of $613 million, or $0.51 a share, something of a shadow of the $1.42 billion, or $1.16 a share, when hydrocarbon prices were marching toward their peak last year. If you disregard one-time items, however, the bottom line turned to $0.68 a share, beating $0.63-a-share consensus expectations. Revenues were down 18% to $5.53 billion.

Schlumberger operates through two units. Its oilfield services segment, which generates about 90% of its business, saw revenues decline about 18% from a year ago. And its smaller WesternGeco unit, which is primarily involved in seismic activities, generated 17% lower revenues than in the comparable quarter in 2008.

As I've told Fools previously, if you want to get a handle on the status of various components of the global energy industry, simply read Schlumberger's quarterly earnings release. In addition to superbly recapping the global energy scene, the company does a yeoman's job of describing a variety of ways in which its technologies have been applied to worldwide exploration and production challenges.

For instance, as Halliburton (NYSE:HAL) and Weatherford (NYSE:WFT) both noted in assessing the macropicture earlier in the week, North American gas drilling has virtually fallen off the cliff. According to Schlumberger CEO Andrew Gould, it's now at its lowest ebb in five years, and the company doesn't anticipate that it will begin to recover prior to 2010. At least partially as a result, "a number of projects are continuing to be postponed or cancelled," a situation that, "if it persists, will lead to inadequate supply when demand growth returns."

Technologically, Schlumberger noted that "A world record formation pressure-while-drilling job has been run in a deepwater Chevron (NYSE:CVX) well in the U.S. Gulf of Mexico ... in 92 days, beating the plan by 40 days." And "In Azerbaijan, Schlumberger Testing Services performed a complex offshore high-pressure, high-temperature well test for BP (NYSE:BP), during which a number of technical challenges were overcome ... "

We'll get a broader picture of the worldwide energy picture as the likes of ExxonMobil (NYSE:XOM) and ConocoPhillips (NYSE:COP) report their quarters. But beyond that, any improvement in the industry by necessity will include Schlumberger. And since such a recovery is inevitable, Schlumberger, in my opinion, constitutes an ideal holding for Foolish investment portfolios.   

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Fool contributor David Lee Smith doesn't own shares in any of the stocks mentioned above. He welcomes your questions, comments, or kibitzing. The Fool has an ironclad disclosure policy.