The downturn in oil prices is really starting to separate the strong oil companies from the weak. With Oasis Petroleum (NYSE:OAS) now firmly in that former category after delivering surprisingly strong third-quarter results, after it beat earnings estimates by $0.03 per share. That strong result was driven by the following three numbers.

1. 50,546 BOE/d
The foundation of Oasis' strong showing was its production, which averaged 50,546 barrels of oil equivalent per day, or BOE/d, during the quarter. That was above the top end of its guidance range of 48,000 to 50,000 BOE/d and represented 10% year-over-year growth. The company accomplished this feat by completing 20 wells during the quarter, which delivered better-than-expected production. CEO Thomas Nusz specifically pointed out that the company continues to "deliver strong performance using our high-intensity completions."

What Nusz is referring to is using a higher volume of proppants in each well, which is boosting production rates. This is a trend that's boosting production across the industry. Whiting Petroleum (NYSE:WLL), for one, has noted that wells completed with its enhanced completions in the Bakken during the third quarter, which had average sand volumes of 5.2 million pounds, delivered an average 30-day production rate of 1,102 BOE/d. That's a 44% increase in productivity over wells drilled in the second quarter using 3.5 million pounds of sand. Even more impressive were two monster wells Whiting Petroleum reported that delivered an average initial production rate of 5,224 BOE/d per well after being competed with a hybrid-style completion using 7 million pounds of sand per well. Clearly, these companies are finding that increasing proppant intensity is the key to unlocking more oil out of the Bakken.

2. $7.67 per BOE
The other key to Oasis' strong quarter was its ability to significantly drive down its operating costs. During the third quarter, its lease operating expenses fell to $7.67 per BOE, which was well below the low end of its guidance range of $8.35 to $9.00 per BOE. This shift really helped take the sting out of lower oil prices during the quarter. It's also worth noting that Oasis' costs are well below those of Whiting, which is guiding for its lease operating to fall to a range of $8.00 to $8.50 for the fourth quarter.

3. $74.6 million
The combination of stronger production and lower costs really came together to deliver what was Oasis' most impressive accomplishment this quarter, which is being cash flow-positive. According to the company's calculation, which is adjusted EBITDA ($189.2 million) minus cash interest ($36.5 million) and capex ($78.5 million), it generated $74.6 million in free cash flow during the quarter. That is the rarest of rare feats in the energy sector these days, when most companies are just trying to shoot for cash-flow breakeven at some point in the not-to-distant future.

Whiting Petroleum, for example, doesn't expect to hit cash-flow breakeven until next year, where it still needs an average oil price of $50 per barrel to generate the $1 billion in discretionary cash necessary to fund the $1 billion capex budget required to keep production flat next year. That makes Oasis' ability to generate free cash flow even more impressive because it's doing so while growing its production.

Investor takeaway
Oasis Petroleum really produced an impressive quarter, all things considered. Although oil prices fell 20% during the quarter, the company still managed to be cash flow-positive, even while growing its oil production. That's something few of its peers can match, with most just trying to claw back to breakeven.

Matt DiLallo has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.