As we’ve highlighted before, the integrated oil majors are truly in a league of their own. The group is responsible for the bulk of the world’s energy production and includes some of the largest and most profitable corporations on the planet. Their sheer scale and global reach makes them ideal investments in the sector, especially as we continue to crave more and more energy. Still, that doesn’t mean there aren’t plenty of other successful energy firms in the sea.

Some of the most exciting opportunities for investors actually lie with some of the slightly smaller independent oil and natural gas producers. Like their major brethren, many of these firms feature just the right combination of exploration & production assets, midstream operations and some downstream marketing or refining capabilities to make them immensely profitable.

At the same time, the bulk of their revenues stem from production at the wellhead, which is key as it makes the independents highly sensitive to long-term rising oil and natural gas prices. Plus, their size does offer some advantages as well. Like Goldilocks, these slightly smaller firms are just the right size to be attractive buy-out targets for the majors or other state-owned oil companies, and to also have plenty of room for growth if those buy-outs never occur.

Overall, looking beyond the majors could provide some of the best long term ways to play our growing energy needs. Take a look at these three E&P buys that are outside of the majors:

Hess

While most of us think of those collectible toy trucks from our youth when we think of Hess (NYSE:HES), the firm is a actually a globally integrated machine with a hand in exploration, transportation and refinery assets. Like its larger integrated sisters, Hess is benefiting from several broad trends affecting the energy industry.

First, the company is tied mostly to oil production, which represents roughly two-thirds of its energy mix. That’s important given how depressed natural gas prices have been lately. Plus, a huge area for growth within those oil assets has been Hess’s exposure to the shale-oil rich Bakken field in North Dakota. Hess operates on more than 800,000 acres in the region and plans to operate an average of 16 rigs here throughout 2012.

The company’s goal is to ramp up production to reach 120,000 BOE per day from its properties by 2015 and recently began shipping roughly 50,000 barrels a day of Bakken crude oil by rail during the second quarter. Likewise, the firm’s robust holdings across the Eagle Ford Shale and the Utica Shale will contribute to its growth long term.

Hess also seems to be smartly divesting assets — such as its 2.72% interest in the Chirag, Azeri, and Guneshli Fields in Azerbaijan — and plowing those profits back into high-impact exploration areas will continue to lift its earnings, cash flow and stock valuation.

Speaking of valuation, Hess currently can be yours for a forward P/E for around 8.5 — cheaper than its much larger integrated rivals. Exxon Mobil (NYSE:XOM) is currently trading for a forward P/E of more than 11, for example. All in all, for investors looking for a cheap integrated play with growth potential, Hess can fit the bill.

Occidental Petroleum

Like many of its peers, Occidental Petroleum Corporation (NYSE:OXY) reported lower second quarter earnings this year due to falling commodity prices. However, Occidental’s focus on oil production allowed it to realize a better quarter than most and — like Hess — the bulk of that production has come from new unconventional sources.

Of Oxy’s roughly 766,000 BOE per day production numbers, the Permian Basin accounts for nearly 55% of its domestic oil production, 53% of its domestic natural gas liquids production and 18% of its natural gas production. That’s a good place to be as the Permian represents one of the cheapest unconventional fields in the nation. Higher production and rig costs represent one of the main challenges facing the E&P set in the current energy price environment.

Those relatively lower costs have helped the company bolster its balance sheet and cash flows, while also creating a steady capital investment program to boost long term growth. That program includes high growth areas such as the Middle East and Latin America.

Oxy can currently be bought for slight premium versus the majors, but given its position in some of America’s cheapest fields and higher growing international regions, that premium is certainly justified — especially if you consider the firm’s 2.35% dividend yield.

Apache

For investors looking for “wildcatter spunk” in the shell of major energy firm, Apache (NYSE:APA) could be exactly what they are looking for. Throughout the firm’s history, it has geared its portfolio towards short-life, high-intensity assets and more challenging operating environments such as the Gulf of Mexico and North Sea. That spirit still continues as Apache explores unconventional energy prospects in such far-flung areas like New Zealand, Kenya and South America.

But like the previous two superstars on this list, Apache has begun to focus on more cash flow steady assets and is now the second-largest player in the Permian Basin alongside Occidental, Chesapeake Energy (NYSE:CHK) and Exxon. Apache’s Permian Basin assets in Oklahoma and the Texas Panhandle are contributing 55,200 BOE per day to the firm’s production.

Plus, Apache is quite cheap on a metrics standpoint given its blend of high-growth and stable assets. It has a forward P/E of 8.6 that puts it directly in the middle of the pack on this list, but could also make it a real long-term bargain as it continues to benefit from long-term energy trends.

In the end, while the integrated majors represent the cream of the crop when it comes to energy sector, there are plenty of other opportunities for investors — and the trio of Hess, Occidental Petroleum and Apache make ideal selections to play the energy world outside the majors. 

As of this writing, Aaron Levitt did not own a position in any of the aforementioned securities.