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What: Shares of Western Refining (NYSE: WNR) were spiking today, gaining as much as 11% in intraday trading after a massive earthquake and tsunami hit Japan.

So what: While the disaster in Japan is bad news for almost everyone involved, it could be good news for refiners. Nearly 1 million barrels per day of refining capacity were shut down as a result of the earthquake and tsunami, and it was reported that a Cosmo Oil refinery had caught fire. In addition, there are concerns that the catastrophe could affect Japan's demand for oil, which could bring down global oil prices and benefit refiners as they purchase oil to turn into higher-value products. The latter would be a relief as refiners had been facing a recent sharp spike in prices due to the unrest in the Middle East and North Africa.

Now what: Western Refining wasn't the only refiner that caught a tailwind from the day's events as Valero (NYSE: VLO), Tesoro (NYSE: TSO), and Holly (NYSE: HOC) all rose more than the broad market. However, uncertainty is still the watchword here. It doesn't appear that there has been any other refinery damage reported other than the Cosmo site, and Petrobras (NYSE: PBR) at least has been quick to say that its 100,000-barrel-per-day Nansei Sekiyu refinery was unharmed.

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