By now, most investors know the energy sector has had a rough ride over the past few months, to say the least. The price of oil in the United States has collapsed from $108 per barrel all the way to $77 per barrel. That represents a drop of nearly 30% in just a few months' time. As you'd expect, earnings reports out of the oil and gas sector are reflecting the carnage rippling through the oil market. Analysts have downgraded stocks across the sector and reduced their earnings estimates going forward based on the possibility of even lower oil prices.

With all of this going on, it might seem ridiculous to consider buying an energy stock. But it's worth noting that Schlumberger (NYSE:SLB) is no run-of-the-mill energy stock. It has a unique business model that sets it apart from many of its peers in the oil and gas space. This allows it to produce solid results, and the end result is that Schlumberger stands out as a diamond in the rough in the energy sector.

A different kind of energy company
Schlumberger isn't like the typical oil and gas companies investors are accustomed to. Schlumberger provides a unique set of technologies and oil field services. This insulates the company against sudden downturns in the price of oil. Last quarter, Schlumberger's revenue rose 8.6% year over year, to $12.6 billion. Earnings per share from continuing operations rose 16% in the same period. The company's best-performing operating segment was reservoir production, where Schlumberger's well services are performed. Schlumberger's diverse business model paid off, as all of the company's groups reported growth. Management attributed this to penetration of the company's new technological solutions.

To be sure, Schlumberger is at risk when oil prices fall, only in a much more indirect way than traditional oil and gas companies. If the price of oil declines dramatically, Schlumberger could see demand for its services fall. That would happen because lower oil prices incentivize oil producers to cut capital expenditures in light of dwindling returns on new projects. But there is really only cause for alarm if the price of oil outright crashes, which hasn't quite happened yet and is unlikely to, given the buoyant demand for oil across the world in places like emerging markets.

That is why, even though oil prices fell considerably last quarter, Schlumberger still held up well. Although commodity price fluctuations are hurting energy companies right now, efficiency is a recurring theme for oil and gas producers. Schlumberger's services help its customers increase productivity, which helps explain its strong operating results amid a poor climate more broadly. The hydraulic fracturing revolution, for example, might not have been possible without Schlumberger's BroadBand Sequence fracturing technique, which is being utilized by clients to improve efficiency in the Eagle Ford shale in South Texas.

Strong cash returns to shareholders
The investment case for Schlumberger is strengthened by the fact that it is a very shareholder-friendly company. Schlumberger buys back boat-loads of its stock as a way of returning some of its cash flow to shareholders. Over the first nine months of 2014, the company has spent $3.5 billion on share repurchases, which is more than double the $1.5 billion spent on share repurchases through the same period last year.

Schlumberger is also an excellent dividend growth stock. The stock yields 1.7% right now, which doesn't seem like much, but Schlumberger has nearly doubled its payout over the past four years.

If you're considering buying the stock, now might be a good time to look closer. Investors who are interested in the company have the opportunity to scoop up shares for a 17% discount from its 2014 highs. Because of this, the valuation is attractive considering Schlumberger's earnings growth. The stock trades for 15 times forward earnings estimates, which is a good value considering its track record of growth.

While there's no telling where oil prices are headed next, Schlumberger's unique business model provides a measure of safety against volatile commodity prices. Plus, the company buys back a healthy amount of its own stock and pays a growing dividend, both practices that serve as added margins of safety.