There was plenty of fuss about Penn Virginia Corporation's (NYSE: PVA) potential earlier this year after billionaire investor George Soros' fund took a 9.2% stake in the company.

Since this announcement, however, the company's shares have retreated. Investors seem to have forgotten about the company's potential. A recent note from Wall Street analysts that concluded that Penn could jump 50% from current levels reignited interest, though.

Multiple catalysts
Analysts believe that there are two major factors that will be catalysts for Penn's shares going forward: the company's valuation, and its output growth.

Firstly, the company is cheap. On a forward basis, the company is trading at an EV/EBITDA multiple of 4.3. Based on the recent equity offering, however, some analysts believe that the company could be trading at a forward EV/EBITDA of 3.8 times as the company has plenty of cash to ramp up high-margin oil growth output. I'll cover this more below.

Still, with 2015 EV/EBITDA ratios in the 4.3 to 3.8 times range, Penn is trading at a significant discount to its peer group. Its peers trade at an EV/EBITDA multiple of 5.1 for 2015.

Drilling activity
The second factor that should drive Penn's growth is drilling activity. As mentioned, with the extra $313 million in cash that was raised from the recent equity offering, Penn has the potential to ramp up high-quality oil volume growth during the second half of this year.

Growth through 2015 should also see a boost as Penn was previously relying on asset disposals to fund growth. The influx of cash from the equity offering will once again allow Penn to increase its oil output.

If Penn is too small for you, though, its larger peer Pioneer Natural Resources (NYSE:PXD) could be a better pick.

Plenty of potential
Like Penn, Pioneer has an attractive asset base with some of the attractive oil real estate within the U.S. Some analysts have placed the value of this real estate at around $400 per share, around 77% above current levels.

There is also Pioneer's potential with the Spraberry/Wolfcamp play. In particular, it is believed that the Spraberry/Wolfcamp holds the largest recoverable amount of resources within the U.S.

Estimates put total recoverable resource at over 75 billion barrels of oil equivalent. Pioneer's share of this is around 9.6 billion barrels, although proven resource attributable to the company is only 432 million barrels.

Nevertheless, Pioneer's other interests around the country give the company a current proven reserve base of 845 million barrels of oil equivalent. The company intends to add 600 million barrels to reserves through exploratory drilling through 2016.

That being said, Pioneer's shares have racked up a gain of more than 100% since the beginning of 2013. As such, some investors may feel that the company looks expensive; this is not the case.

Pioneer is more of a long-term play. For example, the company is basing its future growth on the Spraberry/Wolfcamp. Using the best-case scenario, the company expects to be producing in excess of 1 million barrels of oil equivalent within 10 years. Worst case calls for production of approximately 750,000 barrels per day from the region.

Assuming that the price of oil remains unchanged at $100 per barrel through 2024, Pioneer's gross revenue should be in the region of $100 million per day by 2024. This would make pioneer one of the largest and most profitable oil companies in the world.

Foolish summary
Overall, both Penn and Pioneer are attractive investments. However, Pioneer is more of a long-term play as within the next ten years the company should become one of the world's largest oil producers.

Meanwhile, Penn is set to boost growth during the next few quarters as the company ramps up oil output with new funds. It is also attractively valued when compared to other regional peers.