West Texas Intermediate crude oil prices broke $50 for the first time in more than six months Thursday before easing back below $49 per barrel Friday. If oil starts rising again, the question is where to invest. 

The ability to maintain a low debt level throughout the downturn has played a role in keeping several energy patch players out of bankruptcy courts, and it is one of many factors to consider when choosing oil and gas stocks, according to industry followers.

Stocks of oil and gas industry companies may continue to rise as oil continues its ascent and as investors begin to feel more certain the multi-year low prices hit in February represented the bottom of the cycle. Still, there is always a wild card -- in this case the Organization of the Petroleum Exporting Countries, which meets next week.  

If you want to invest in low-levered players, how about Diamondback Energy (FANG) - Get Report and Energen (EGN) as names to consider? Both of these exploration and production companies operate in the profitable West Texas Permian Basin and are levered below two times their net debt to fiscal year 2017 Ebitda, according to Seaport Global Securities.

These players may have a catalyst in the works, said Topeka Capital Markets analyst Gabriele Sorbara -- the two operators might consider a merger.

"We note that FANG is looking at larger transactions to achieve a large-cap status," she said in a recent note. "We believe there are more opportunities on the private side, but we would not be surprised to see FANG acquire a public company."

Or, consider onshore drilling services provider Independence Contract Drilling (ICD) - Get Report. Zacks Investment Research reported Wednesday the company has a long-term debt to capitalization ratio of 20.8%, which the firm says is lower than the industry average ratio of 30.8%.

FBR Capital Markets analyst Thomas Curran estimates that number may be closer to 4% now following the company's first-quarter capital raising that netted it $43 million, which it planned to use to pay down its revolving credit facility. 

A majority of the 11 analysts who follow the $157 million market-cap company directly rate the stock a buy (or their firm's equivalent rating), according to data compiled by Thomson Reuters. Two company followers rate the stock as a hold, while zero rate it as a sell. The stock closed Friday at $4. 

Meanwhile, Independence Contract Drilling shares are moving in such a way that indicates a near-term breakout is approaching. ICD has now become the only onshore drilling services provider that still has a truly exciting secular growth story, according to FBR's Curran. 

"I think they'll not only be able to quickly re-attain 100% fleet utilization and pricing power, but they'll also win a series of incremental new build awards as I predict a continued shift in technological preference toward pad-optimal tier one drilling," he said. 

Of the 14 rigs in ICD's fleet, 13 of them are marketed and one is decommissioned awaiting an upgrade at the right moment during the oil cycle. All 13 of ICD's fleet are what Curran calls "pad-optimal" rigs, meaning not only do they have state-of-the-art specs in terms of the capabilities of their various drilling systems, they also have an omnidirectional walking system, giving them the greatest possible range of flexibility and moving. 

ICD looks to be able to outpace competitors Patterson-UTI Energy (PTEN) - Get Report and Helmerich & Payne (HP) - Get Reportin inking pad-optimal new building contracts because these larger players will find it harder to win enough awards as their fleets are much bigger. H&P has a fleet of 347 rigs, 51 of which are pad-optimal, while Patterson's fleet has 161 tier one rigs, 53 of which are optimal for pads.

As Friday's announcement from Hercules Offshore (HERO)  demonstrates, even players with low debt on paper can find themselves on the wrong side of lending agreements. Hercules, an offshore drilling services company that has seen its shares obliterated by nearly 80% since it emerged from bankruptcy in November, also made Zacks' list. 

Unlike ICD, which provides drilling service to onshore oil and gas companies, Hercules provides drilling services to an offshore oil industry that industry sources continue to believe could be a ways off from a recovery.

--Claire Poole contributed to this report.