| The animation illustrates Pennsylvania's relatively recent transition from conventional vertical wells (black diamonds) to horizontal wells (red diamonds), drilled mostly in sections of the Marcellus, Utica, and Geneseo/Burket shale formations located in the northeast and southwest portions of the state. The animation also shows that as horizontal drilling increased, the number of vertical wells—which are typically less productive—fell, resulting in an overall decline in the state's new well count. For the full Today in Energy article, visit: www.eia.gov |
