FILE - In this April 15, 2009 file photo, the Halliburton sign adorns the side of a machine being used by the company at a site for natural-gas producer Williams in Rulison, Colo. Halliburton Co. said... more 
FILE - In this April 15, 2009 file photo, the Halliburton sign adorns the side of a machine being used by the company at a site for natural-gas producer Williams in Rulison, Colo. Halliburton Co. said Monday, April 18, 2011, its income for the first three months of the year more than doubled as drilling activity in North America picked up. less 
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Associated Press | Photo By David Zalubowski, File
Mon, Apr 18, 2011 7:27 AM EDT