Not all energy-services companies are created equal. Some, like Schlumberger (NYSE:SLB), are highly internationally diversified, and others, such as BJ Services (NYSE:BJS), depend more on the North American market for their revenue.

Likewise, different companies rely to different degrees on the natural gas market (versus oil), and BJ Services again appears to be on the upper edge here. So even though growth has been just as strong here as at any other energy-services concern, lingering worries about the North American gas market have taken a toll on the stock.

Speaking of actual results, though, revenue was up 36% this quarter as strong results in the U.S. pressure pumping business helped offset slight weakness in international business -- if you really want to call "up 25%" weak. Margins continue to expand, and the company saw operating income jump 84% from last year's level. As was the case for Schlumberger, a harsh winter in Russia did have an impact on results this quarter, but I'd argue that BJ Services still managed to pull out a pretty fair quarter.

Now, as for competition and market risk, it's true that there are some start-up pumping operations in Canada, but what we're seeing in pricing suggests that this new supply isn't exactly sopping up demand. And just like Schlumberger and Halliburton (NYSE:HAL), BJ Services isn't having a hard time finding customers.

The natural gas question is the trickier part. This winter was mild, and that left gas inventories in strong shape, despite a fair bit of Gulf production still being shut in. So the risk, then, is that if we don't have hurricanes or a cold winter this time around, natural gas pricing could be vulnerable. On the flip side, natural gas for December delivery is trading at more than $11, so who the heck knows what's going to happen?

Even if you think BJ Services deserves some discount for its North American gas exposure, a rough comparison with others, like Weatherford (NYSE:WFT), BakerHughes (NYSE:BHI), and Smith International (NYSE:SII), still suggests to me that BJ Services is overly downtrodden. Be cautious, though -- long-term value is tough to find in the energy sector. And don't mistake relative underpricing for real long-term opportunity.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).