Cross-Section of Typical Horizonal Marcellus Well
The process involves starting with vertical drilling followed by horizontal drilling. Vertical drilling ranges from 5,000 feet to 9,000 feet below ground depending upon the depth and thickness of the gas reservoir. When the Marcellus Shale is reached, the well is turned, and horizontal drilling occurs for another 3,000 feet to 10,000 feet or more. At various depths, multiple lengths of steel casing are cemented in place to protect surface water, groundwater, or water supply wells from the potential migration of natural gas in the drilled well. These casings also prevent hydrofracing fluids and deep brine water from leaking and adversely impacting water resources.