Everybody is talking about the price of crude oil and gasoline, and with good reason -- we all use gas to fuel our cars, and the price of crude has implications across the entire economy. But let's not forget natural gas, which is also used nationwide. Many people even heat their homes with it.

If you look back a bit, you'll see an interesting trend. Yes, the price of oil has gone up by about one-third in the past year and has more than doubled from its price two years ago. But during those same periods, natural gas prices have more than doubled and nearly tripled, respectively. The reasons are many and varied and somewhat beyond the scope of this Take. But whatever the cause, a cold winter in the U.S. could spell even higher natural-gas prices.

Who, then, stands to benefit? Not surprisingly, major oil companies like ExxonMobil (NYSE:XOM) and BP (NYSE:BP) are both major players in natural gas. There's also a second tier of independent companies, including Chesapeake Energy (NYSE:CHK), Apache (NYSE:APA), Devon Energy, and Anadarko (NYSE:APC), as well as small up-and-comers like Ultra Petroleum (AMEX:UPL) or Newfield Exploration (NYSE:NFX), that could reap rewards.

I think everybody who follows my work knows the gig on the big boys -- they're good cash flow generators and energy bellwethers, but growth is constrained by low (or negative) production trends. In my mind, then, that leaves the smaller fish as the more interesting plays for growth-focused investors.

Looking simply at valuation in terms of enterprise value-to-barrels of oil equivalent in proven reserves, Anadarko and Chesapeake seem somewhat bargain-priced at $10.80 and $12.74 respectively. Ultra Petroleum and Newfield both look expensive at $34.35 and $23.87, but both companies (and particularly Ultra Petroleum) are increasing production and reserves at a significantly above-average rate. And then you have Apache, which has an OK valuation at $14.29 per barrel, and an OK return on assets, but a sound management team with a very good history.

Traditional valuation models are really tricky to use right now. Nobody has any good idea what the price of natural gas will be in a year or two, and that makes earnings projections tough. Nevertheless, if you consider traditional methods, Apache, Anadarko, and Newfield all look as though they could still be good buys. Then again, you have Ultra possibly getting clearance to significantly increase production, and you have insiders at Chesapeake buying shares. It's a muddy picture indeed, but as long as you think natural gas prices will stay high, these might be some good companies to investigate.

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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).