If you are an investor focusing on the long term, then stable, dividend-paying companies should interest you. Naturally, these businesses must be solid and must continue to grow and create shareholder value for a long time to come.

Why they are the best
As the world's thirst for energy has kept growing, some of the bigger and mature oil and gas companies have done exceptionally well. Consequently, these companies paid out dividends that gradually grew as cash flows increased. Looking into the future, oil and natural gas will continue to be the primary sources of energy. In its Outlook for Energy: A View to 2040, ExxonMobil predicts that oil and gas will continue to be the most widely used fuels in the next three decades, with natural gas consumption overtaking that of coal and ranking just behind oil.

While trying to identify stable dividend payers in the exploration and production space, I found that it wasn't too difficult to spot them. Historically, the best dividend payers were the bigger and more established companies with significant exposure to diverse resources across the globe. These companies could take advantage of gradually increasing (though volatile) crude oil prices and time their production rates accordingly. The net result: These companies guaranteed excellent cash flows, a part of which they paid out as dividends.

Below are four companies in the E&P space that I believe will continue to be solid dividend payers in future.

Royal Dutch Shell (NYSE: RDS-A): The Netherlands-based integrated oil and gas giant has been consistently paying out dividends for the last two decades. That shouldn't come as a major surprise. From developing properties in the deep waters of the Gulf of Mexico to building the world's largest floating LNG facility off Australia, Shell is leaving no stone unturned in its quest to find new reserves. Other major projects include the Qatargas 4 LNG and Pearl GTL in Qatar and the Athabasca Oil Sands Project in Canada. Like all big oil and gas companies, Shell has set its sights on the Asian markets, which are expected to lead the world's energy demand in the future.

In 2011, total shareholder return, including dividends reinvested, stood at an impressive 21.3% while the S&P 500 fell 1% and the Dow Jones Industrial Average returned 5.5%. A dividend yield of 4.7% isn't easy to ignore either.

Statoil (NYSE: STO): Production volumes for the Norwegian company surged in the fourth quarter and management intends to ramp up volumes further, thanks to its acquisition of Bakken shale operator Brigham Exploration. Additionally, more discoveries in the North Sea and possible acquisitions of assets offshore Brazil herald an exciting future for the company. Last month, the company announced another major discovery about 200 kilometers off the Brazilian coast.

Total shareholder return in 2011 with dividends reinvested stood at 16.1% -- again, an impressive return for a 12-month period. With a dividend yield of 4%, this stock looks promising.  

Petrobras (NYSE: PBR): Deepwater resources off the Brazilian coast are among the most exciting prospects in the E&P space today. And Brazil's state-owned Petrobras looks well set to capitalize on these assets. Despite the company's shares falling as much as 34% in 2011, I'm not too worried. The company aims to become the world's largest oil producer over the next decade with plans to spend a massive $224 billion on capital projects in the next five years to get there.

Petrobras has a history of paying special dividends several times a year. A dividend yield at 3.4% isn't bad at all. I believe its stock looks attractively priced compared to its peers, and the upside looks promising.

ConocoPhillips (NYSE: COP): The proposed spinoff of its refining segment is weighing on Conoco. However, I don't think this should have a long-term impact on the company's E&P arm, which represents 66% of the total assets. The company holds some of the most exciting prospects in the Eagle Ford, Bakken and Barnett shale plays. Additionally, the oil sands of Athabasca, Canada, along with the North Sea assets, are capable of pulling up production.

In short, Conoco has the potential to sustain dividend payments. Total shareholder returns for 2011 (with dividends reinvested) were 10.7%, while current dividend yield is 3.4%. A great stock for years to come.

Foolish bottom line
While these stocks are among the best dividend payers in the E&P sector, your search shouldn't end here. Moreover, it must be kept in mind that dividend payers definitely counteract risk as compared to non-dividend stocks. If you're looking for more ideas, The Motley Fool has created a new special oil report titled "3 Stocks for $100 Oil," which you can download today, absolutely free. Just click here to access it now.