In addition to extended reach, horizontal drilling drastically increases production. In "tight" rock (low permeability) like the Barnett Shale, the gas uses fractures to move out of the rock and into the wellbore. The fractures may be natural or induced (see below). A horizontal well exposes more rock (and therefore more fractures) to the wellbore because it is usually designed with the horizontal portion of the well in the productive formation.
