The Fayetteville Shale spans across Arkansas in a belt, approximately fifty miles from north to south, running from the north through the central part of the state to the Mississippi River on its eastern flank and encompassing 9,000 square miles. The deposition is an unconventional "tight sand" resource, characterized by low permeability, which requires reservoir stimulation to enhance the permeability so the gas may be produced. The Fayetteville Shale is as "tight as a tick" with permeability measured by nanodarcies as opposed to millidarcies. The Barnett Shale play in Texas is the first modern shale gas development and the progenitor of the present shale-gas boom in the United States. The successful development of the Fayetteville Shale in Arkansas is a consequence of the advancement in hydraulic fracturing (fracing) and horizontal drilling technology developed in the Barnett Shale. The first Fayetteville Shale well was drilled in 2004, and there are currently 1,841 producing Fayetteville Shale wells in the state. The first wells drilled were vertical wells, but they were not very productive. Ninety percent of the wells drilled into the "sweet spot" of the Fayetteville Shale play, known as the B-43 area, are horizontal wells. to Fracing along the lateral section of the horizontal well increases the extent of the productive area of enhanced permeability, and also, the extent of well-bore drainage of the horizontal well over the fractured vertical well. Horizontal wells also offer the opportunity to reduce the environmental footprint of surface-producing operations. One surface well location can support several subsurface horizontal laterals and, therefore, avoid multiple surface well locations, access roads, and gathering-pipeline locations.