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What: Shares of small-cap oil and gas driller Bronco Drilling (Nasdaq: BRNC) were on fire today, climbing as much as 16% after the company announced fourth-quarter results.

So what: For the quarter, Bronco's revenue leapt 135% from the same quarter last year, while earnings per share -- excluding one-time charges -- came in at $0.06. Revenue of $37.3 million topped the $36.7 million that Wall Street analysts expected, while the adjusted EPS bested an estimated $0.01 loss.

Now what: Fellow onshore driller Union Drilling (Nasdaq: UDRL) also posted positive fourth-quarter results, and its management team had some optimistic comments about what's ahead for 2011. Specifically, they noted that dayrates have started to firm up and that there's a growing demand for oil versus natural gas drilling. The excitement pushed Union's stock up as much as 37%, while other drillers, including Vantage Drilling, also appeared to get a bump from the news.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.