As InvestorPlace contributor Aaron Levitt recently explained, the energy sector is a game run mostly by the major names, and it doesn’t take much of a scorecard to figure out who those players are: Exxon (NYSE:XOM), Chevron (NYSE:CVX), Royal Dutch Shell (NYSE:RDS.A, RDS.B) and Conoco (NYSE:COP) just roll off the tongue when talking about oil, gas and energy.

And why not? With a combined market cap of $900 billion the Big Four pretty much rule the energy world, and investors clamor for their shares. All four produce healthy doses of profits, dividends and financial strength.

But there are other ways to play the game and put a few other names on the scorecard. Some lesser-known players may be a little riskier from a financial standpoint, but they have share prices that invite rather than frighten investors and can certainly hold their own in a dividend portfolio.

Here are four of my favorite small-ball oil, gas and energy plays.

Murphy Oil

Murphy Oil (NYSE:MUR) is an El Dorado, Ark.-based producer that started out in 1907 when the first oil field was established in the Caddo Field in North Louisiana.

Murphy produces oil and gas, and operates retail gasoline stations under the Murphy USA brand across 23 states in the U.S., with most located in parking areas of Wal-Mart (NYSE:WMT) Supercenters. Having your brand associated with Walmart in the Southern U.S. isn’t such a bad idea, and following the formula of low-cost provider isn’t so bad, either.

Murphy’s market cap of $10 billion pales compared to any of the Big Four, as do recent 2011 revenues of $28 billion. But here’s what I like: Murphy has paid a dividend to shareholders since 1961, a substantial 42-year run. And since its payout ratio is just 24%, the run should continue.

That dividend of $1.24 per share gives you 2.26% dividend yield, below Exxon’s 2.59%, but at a share price just under $30 less. One caveat: The stock has underperformed the market a bit, and growth has been a little up and down, with market forces buffeting Murphy in 2009. But for a long-term dividend play on a fairly easy entry price of $55 per share, it’s worth the risk.

Marathon Oil

Marathon Oil (NYSE:MRO) is a Houston-based international energy company engaged in exploration and production, oil sands mining and integrated gas operations around the world. It was founded in 1887, and at one point was one of John D. Rockefeller’s Standard Oil (now part of Exxon) Trusts.

Like most oil and gas companies, Marathon has grown organically and through acquisitions. Today, it’s a $19 billion market cap conglomerate with just over $14 billion in revenues. Earnings growth is steady if unspectacular, which says a lot for a smaller company in this segment because gas and oil prices can whipsaw anyone off the oil rig.

Dividends keep chugging along, having been paid out since 1991 at a steady clip. At 68 cents per share annually, the dividend could use some help, but Marathon’s share price of around $27 per share nets investors a solid 2.5% dividend yield. And as with Murphy, a low (26%) dividend payout should make long-term investors feel comfortable the payout will last a very long time.

Marathon Petroleum

Findlay, Ohio-based Marathon Petroleum (NYSE:MPC) was spun off from Marathon Oil in June 2011 to become an independent petroleum products refiner, transporter and marketer. Marathon Petroleum now stand on it own, operating six refineries in the Gulf Coast and Midwest with an aggregate crude oil refining capacity of approximately 1.2 million barrels per day.

Marathon Petroleum may be a newly formed entity, but it’s not a new company. As an $18 billion market cap and first year revenues of over $68 billion show, it’s pretty firmly established. Here are just a few more bona fides: MPC is the nation’s fifth-largest refiner and the Midwest’s largest. It owns a six-plant refining network, an extensive terminal and transportation system, and the nation’s fourth-largest chain of company-owned and operated retail gasoline and convenience stores.

With a very healthy $1.40 per share dividend right out of the box, Marathon Petroleum sports a 2.77% dividend yield. It, too, has a nice entry price at just around $50 per share. By the way, the dividend payout ratio is just over 10%, so investors should look forward to a long relationship.

Valero

San Antonio-based Valero (NYSE:VLO) is an independent petroleum refining and marketing company producing gasoline, distillates, jet fuel, asphalt, petrochemicals, lubricants and other products too hard to pronounce or explain.

Here’s what’s easier to explain: Valero owns 10 ethanol plants in the Central Plains region with a combined production capacity of about 1.1 billion gallons per year, and it maintains a refining capacity of 3 million barrels per day, making it the world’s largest independent refiner.

All of which adds up to a $16 billion market cap company with $138 billion in revenue for its 2011 fiscal year. Valero has paid out a dividend since 1997, standing today at 68 cents per share for a dividend yield of 2.43%. The price of entry is under $30 per share, and Valero comes in with the lowest dividend payout ratio of our group at just over 8% of earnings, a wide margin for future increases.

Marc Bastow is an assistant editor at InvestorPlace.com. As of this writing he was long XOM.