The U.S. has abundant natural gas resources within the Barnett Shale, Haynesville/Bossier Shale, Antrim Shale, Fayetteville Shale, New Albany Shale, and Marcellus Shale. This article is focused on the Marcellus Shale because it is the most expansive shale gas in play in the U.S. The Marcellus Shale, which is Devonian age (416?359.2 My), belongs to a group of black, organic-rich shales that are common constituents of sedimentary deposits. Natural gas extraction in the Marcellus Shale is currently an expensive endeavor. A typical horizontal drilled well, using multistage fracturing techniques, costs roughly $3?5 million to complete. The large amount of water used, and management of the wastewater are also very costly factors.