Horizontal drilling offers several efficiencies. Extending upwards of two kilometers in length, horizontal wells expose the wellbore to a larger part of the reservoir. In addition, land disturbance is decreased because multiple wells can be drilled from a single pad. Conversely, vertical wells require a separate site for each wellbore.
Until recently, shale gas reserves were uneconomic to produce. Today, natural gas in shale formations can be accessed via horizontal drilling. Horizontal drilling utilizes a flexible drilling pipe that starts vertically, but is gradually angled to run horizontally through the shale formation.