For independent oil & gas drillers especially, 2013 has been the year of unconventional plays. But for a company to sit on some coveted acreage in one of highly sought after shale formations of the US and Canada is not in itself a guarantee of success.

The natural gas and to a significantly lesser extent crude oil that is broken out of rock formations to be pumped to the earth’s surface might be plentiful, but even with the newest technologies like seismic imaging, hydraulic fracturing, and horizontal drilling, there is no getting around the fact that most of the sweet spots in a given shale play will have a significantly shorter lifespan than their conventional counterparts. Even if a driller is lucky enough to be sitting on one of these sweet spots, it may have a difficult time when these become exhausted, and it is forced to redirect efforts to smaller and more disparate pockets of oil and gas.

This situation can be particularly problematic for the independent oil and gas companies who have ostensibly beat their “super-major” counterparts to the punch on shale over the last few years. And as shale plays become more and more costly, it may only get worse. Most of the shale formations in the US are plentiful in natural gas, which is advantageous for many reasons, including that it is a cleaner-burning form of energy than oil. In terms of profits and revenues, however, natural gas is nowhere near as valuable as crude, which has hovered around $100 per barrel for a significant portion of 2013.

For investors looking for an equity-based entry point into shale-based resources, small-caps and independents are likely still going to be the way to go for the near to mid-term. The following five small-cap independent oil & gas industry stocks may be worth a look due to strong performance throughout the year that is replicated in a strong perfomance during the month of November. Furthermore, these companies despite their size have managed to keep up positive, if not impressive operating margins for small-caps in the oil & gas industries, indicating that they can sustain drilling and pumping into the next year.

Quicksilver Resources Inc. (KWK)

Market-Cap: $501.31 million

Price: $2.92

Operating Margin: 30 percent

November Performance: +32.73 percent

Shale plays: Barnett Shale, Texas; Horn River Basin, Canada

Gastar Exploration Ltd. (GST)

Market-Cap: $337.84 million

Price: $5.89

Operating Margin: 25.20 percent

November Performance: +43.66 percent

Shale Plays: Marcellus Shale, West Virginia

Abraxas Petroleum Corp. (AXAS)

Market-Cap: $332.91 million

Price: $3.60

Operating Margin: 21.30 percent

November Performance: +21.30 percent

Shale Plays: Permian Basin; Alberta, Canada

Penn Virginia Corporation (PVA)

Market-Cap: $702.44 million

Price: $10.73

Operating Margin: 4.80 percent

November Performance: +44.80 percent

Shale Plays: Eagle Ford & Haynesville Shales, Texas

Genie Energy Ltd. (GNE)

Market-Cap: 325.65 million

Price: $16.80

Operating Margin: 2.30 percent

November Performance: +52.45 percent

Shale Plays: Colorado, Israel