Nomac Drilling Corp. derrick man Justin Spruell, right, climbs down from an overhead platform after connecting a section of drill pipe on a Chesapeake Energy Corp. natural gas drill site in Bradford County, Pennsylvania, U.S., on Tuesday, April 6, 2010. Companies are spending billions to dislodge natural gas from a band of shale-sedimentary rock called the Marcellus shale that underlies Pennsylvania, West Virginia and New York. The band of rock, so designated because it pokes through near a city of that name in northern New York, may contain 262 trillion cubic feet of recoverable gas, the U.S. Department of Energy estimates. Photographer: Daniel Acker/Bloomberg *** Local Caption *** Justin Spruell US proven oil reserves last year rose to their highest level since 1975, official figures have shown, in the latest sign of how the shale revolution has transformed the country’s energy supply outlook. Proven reserves — oil that is […]