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"  1. North Dakota&amp;#039;s Bakken Formation is a layer of dense, oil-bearing rock found at a depth of about 2 miles. To tap it, oil companies drill to the hydrocarbon-rich stratum, then curve the well bore 90 degrees so that it runs horizontally through the thin, irregular formation.  2. Hydraulic fracturing, or fracking, typically frees oil by cracking rock with high-pressure bursts of water, sand, and chemicals. Tight rock in shale-oil plays like the Bakken requires multistage fracking to maximize oil recovery.  3. In multistage fracking, engineers perforate short segments of the production casing independently. This allows them to concentrate the hydraulic assault, creating longer cracks that allow more oil to flow to the well.  &amp;amp;gt; &amp;amp;lt;&amp;amp;lt;&amp;amp;lt; America&amp;#039;s Next Oil Boom  How North Dakota&amp;#039;s Oil Gets to You &amp;amp;gt;&amp;amp;gt;&amp;amp;gt;  "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/science/energy/a7700/fracking-illustrated-a-guide-to-shale-oil-extraction-9654630/?src=rss>