The Marcellus Shale occurs throughout much of Pennsylvania, upstate New York,
eastern Ohio and West Virginia. It also underlies smaller
areas of western Maryland, eastern Kentucky and Tennessee,
and extreme western Virginia.
In 2003 a promising natural
gas well was drilled in Washington
County, Pennsylvania.
The drillers found success in using some of the horizontal drilling and hydraulic
fracturing methods that worked in Texas. By the end of 2007,
over 300 Marcellus Shale gas wells had been drilled in Pennsylvania alone. Many more are anticipated throughout the Appalachians.
Some researchers believe that
as much as 500 trillion cubic feet of natural gas may exist in the Marcellus. Perhaps 10% of that gas (50
trillion cubic feet) might be recoverable, which would be
enough to supply the entire United
States for about two years.
The economic value of the Marcellus natural gas is enhanced by its proximity to many big cities.
Many property owners have
been enriched through leases of mineral rights and royalties paid for
successful Marcellus gas production.
Such rewards are not without risks, however. Some groundwater supply wells have been adversely impacted by leaks, spills and groundwater
redirection problems. Most states in the Appalachians are ramping up permitting programs in response to
Marcellus activity and the associated environmental risk of hydraulic fracturing.
Large amounts of water are required for hydraulic fracturing, and large quantities of
potentially contaminated wastewater are generated. The fracturing process
itself can generate small local earthquakes because of the high pressures
involved. Some reports exist of possible groundwater supply contamination
and land subsidence effects.
