As prospective investors no doubt have noticed, there's an energy boom going on in the U.S. right now that could bring us a new No. 2 state in the oil-producer rankings behind Texas. I'm talking about the largest producer of spring wheat, North Dakota.

The combination of high crude oil prices, together with some rather amazing technological developments—horizontal drilling and hydraulic fracturing, or fracking—have allowed companies to find and produce oil and natural gas in fields where it previously made no economic sense to do so.

In a March 2008 edition of my weekly newsletter, I wrote the following: "The Bakken oil formation reserve, discovered in 1951, covers about 200,000 square miles, including parts of South Dakota and Montana. The potential is said to be as much as 200 billion barrels. That's a lot, even using Fed math. In 2007, a company called EOG Resources, based in Houston, completed a well near Parshal, N.D., 'that is expected to yield 700,000 barrels of oil'. The USGS completed a study in 1999 that indicated that a reserve of as much as 400 billion recoverable barrels of oil were in the (Bakken) field." Now, that's a bunch.

Along with the Bakken field, we're also seeing significant development occurring in Pennsylvania and New York in what's called the Marcellus region. And don't forget the ongoing work being done in Canada with the oil sands and shale.

Due primarily to the work in these two U.S. fields, we have reversed a 20-year decline in energy independence. The U.S. Department of Energy said that the proportion of the demand for energy within the country being met from domestic sources during the last six years rose to an estimated 81 percent in 2011.

I believe that this growth is likely to continue with very little real impact from solar, wind, or whatever. The International Energy Agency projects that these non-fossil energy technologies will satisfy only a little more than 2 percent of the world's energy demand by 2030, and that's assuming they'll still get those mega-subsidies.

So how do you, as an investor, benefit from and participate in what looks to be a long-term growth sector? Carefully. Here are a few points to consider before I give you some companies to review.

As this is written, the unusually warm winter in most of the U.S. and uncertainty about the extent of oversupply during the next few years are adding to the current bearish sentiment on natural gas. The operative phrase is current oversupply, as this makes share prices lower and that much more attractive.

With crude oil, if prices for products coming from the Bakken drop below $65 a barrel—it's about $70 right now—that might force some producers in the region to scale back development. While price drops don't appear to be a problem, given the global energy demand and political picture, these prices can be affected by increased production in the area and the lack of an effective infrastructure to get the product to refining and distribution points. Other unknowns include determining how to get more production from less investment, well inventory waiting on completion, weather, and the timing of the uptick in domestic and global demand to absorb the current excess supply.

The upsides for companies in this sector include large profit margins in the international market and growing demand from Japan and various emerging markets. Also, there's the security of both the source and delivery systems within North America. All of these combine to create a good foundation for long-term price appreciation.

Following are five stock ideas for growth-oriented investors and a couple for total-return-oriented investors.

The companies I refer to here are certainly not meant to represent your only choices nor should they be considered as quick trades. I strongly suggest you do your own homework to determine where or if they have a place in your holdings. Further, owning more than one is also a good idea so as to not be too concentrated.

From a land ownership perspective, Northern Oil & Gas (NOG) looks good. Though paying no dividend, the company's ownership of properties in both the Bakken and Marcellus fields is a definite long-term advantage. And last year, according to Investor's Business Daily, the company posted a profit margin of 58 percent.

To get the stuff out of the ground, you need to drill for it. Helmerich & Payne (HP), Nabors (NBR), and Patterson-UTI Energy (PTEN) together control about 50 percent of the unconventional (horizontal) shale drilling market and perhaps 90 percent of the industry's most powerful rigs, versus about 30 percent of the overall land rig market.

Ultra Petroleum (UPL) is a small, independent exploration and production firm that, according to Morningstar Research, holds some of the best assets in North America in the Pinedale Field of Wyoming and Marcellus Shale of Pennsylvania. Almost all its production is dry natural gas. Morningstar believes that Ultra's acreage should support a decade or more of double-digit production growth, given "the tight spacing required for full development in the Pinedale and the emerging nature of the Marcellus." Though it pays no dividend, Morningstar is quite positive about its stock price potential from here.

There are two exchange-traded funds that also may warrant your consideration. One has been around for a while; the other is quite new.

The older one, called the U.S. Natural Gas Fund (UNG), trades on the New York Stock Exchange and is a way to play natural gas, generally. It's neither tied directly to any particular field nor does it pay a dividend. However, it is a way to participate in the upside of gas prices generally without having to pick a particular company as an investment.

The newer one, whichcame to market in February, is called the Market Vectors Unconventional Oil & Gas ETF (FRAK).The creation of this ETFcame about as a result ofthe interest in the unconventional oil and gas plays discussed in this article.Each company included in this portfolio must generate at least 50 percent ofits revenue from the production of unconventional oil and natural gas resources, such as oil sands, shale gas, or coal bed methane.An important consideration is that, as withany new ETF, even those createdon ahighly credible premise,sufficient trading volume must be built before they're suitable as an investment.You need to haveliquidity.

And finally, here are the total-return (growth plus income) suggestions.

Linn Energy (LINE) offers a generous 7.5 percent current yield and has more than doubled its income distributions during the last six years. According to Credit Suisse, consensus earnings estimates for fiscal years 2011 and 2012 have increased during the last two months. The company has had compounded earnings growth of 40 percent annually during the past five years, and analysts have it earning $2.20 per share in 2012.

Enerplus Corporation (ERF) is based right up the road in Calgary. I like these guys for a number of reasons. The company has exposure in Alberta, Saskatchewan, British Columbia, and Manitoba for oil sands and shale. It also has a presence in Montana, Wyoming, Utah, and North Dakota for the Bakken play, as well as Maryland and Pennsylvania for the Marcellus play. Enerplus has 42 percent of its production in crude oil and natural gas liquids, with the rest in natural gas. To cap off the geographic and product diversification, it pays a 9 percent current dividend.