Craig Paradis (L) of Advance Drilling, operates the brake handle on a drilling rig for Crescent Point Energy as two roughnecks add a pipe extension to drill deeper into the Bakken formation near Oungre, Saskatchewan in this picture taken June 20, 2012. Exxon Mobil Corp will buy Denbury Resources Inc's properties in the Bakken shale for $1.6 billion and the exchange of some assets as the world's largest publicly traded energy company seeks to boost its crude oil output. The use of technologies like hydraulic fracturing and horizontal drilling have unlocked vast supplies of oil and gas. Output in the Bakken - which spans North Dakota, Montana and Canada - is expected to double to about 1.2 million barrels per day by 2015. Picture taken June 20, 2012. REUTERS/Rod Nickel (CANADA - Tags: ENERGY BUSINESS)