Allegheny River Headwaters Watershed Conservation Plan
Allegheny River Headwaters Watershed Conservation Plan
Allegheny River Headwaters Watershed Conservation Plan
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<strong>Allegheny</strong> <strong>River</strong> <strong>Headwaters</strong> <strong>Conservation</strong> <strong>Plan</strong><br />
Chapter 2. Land Resources<br />
important forests serving as critical habitats. Forest fragmentation affects wildlife through habitat loss and<br />
increasing susceptibility to predators. Contaminated groundwater from insufficient case piping, leaking or<br />
flooded waste fluid holding pits, or drilling site spills can penetrate into private water well aquifers.<br />
Another potential contaminate of private water wells from gas wells is the migration of methane gas,<br />
which in hard to detect and poses an explosive hazard.<br />
Marcellus Shale<br />
The Marcellus shale is the second largest shale formation in the U.S. and is among the top natural<br />
gas shales in the world. Found in the Appalachian Region it extends 575 miles through West Virginia,<br />
Ohio, Pennsylvania, and New York. It received its name from the discovery of the first outcrop in<br />
Marcellus, New York in 1839. Formed during the Devonian period, the black shale is slightly radioactive<br />
with a low density and is organically rich. These naturally occurring organic carbons may include<br />
methane, ethane, propane butane, and other hydrocarbons (petroleum). Naturally occurring radioactive<br />
materials, or NORM, found in Marcellus shales may include elements, such as uranium, radium, thorium,<br />
and radon (Bishop, 2009).<br />
In 2002, it was believed that 1.9 trillion cubic feet of natural gas was available for development<br />
within the Marcellus Shale formation in Pennsylvania (National Park Service, 2009). Since then,<br />
additional studies have been conducted, and now the Marcellus Shale formation is believed to have the<br />
potential to produce nearly 500 trillion cubic feet of natural gas. It is believed that the amount of natural<br />
gas produced from the Marcellus Shale formation could support the entire U.S. for more than 20 years<br />
(Engelder, 2009).<br />
Natural gas recovery within the Marcellus shale formation is a relatively new industry in<br />
Pennsylvania. The number of permits issued within Pennsylvania for Marcellus shale gas wells increased<br />
from 475 permits in 2008 to 3,314 permits issued in 2010 (DEP, 2011).<br />
Natural gas within the Marcellus shale formation occurs within pore spaces, fractures, or breaks in<br />
the shale. It can also be absorbed in mineral grains and<br />
organic material. The Marcellus gas is an unconventional<br />
gas, meaning that it requires stimulation and work in order<br />
to recover it. The majority of the gas is located within<br />
pore spaces, which are fine and poorly connected, making<br />
it difficult for the gas to escape. Gas that is naturally<br />
discharged escapes very slowly. Utilizing hydrofracturing<br />
techniques—blasting large amounts of water, sand, and<br />
other chemicals at the shale causing it to fracture—can<br />
establish a network for the natural gas to easily flow<br />
through the created cracks and into wells (DEP, 2010c).<br />
When drilling for natural gas, a vertical well is bored<br />
into the ground. In order to increase permeability and<br />
recover the gas from the Marcellus formation, horizontal<br />
drilling and hydrofracturing are used. When horizontal<br />
What’s in the Slick Water?<br />
Friction Reducer:<br />
An organic polymer or potassium chloride<br />
Wetting agent:<br />
A non-ionic surfactant or soap<br />
Biocide:<br />
Toxic compound to control micro-organism<br />
growth<br />
Scale inhibitor:<br />
An organic polymer or phosphonate<br />
drilling techniques are used, the cost can more than double, but productivity can increase by 15–20 times.<br />
Hydrofracturing techniques work well in recovering the gas; however, it requires a large volume of water,<br />
up to 300,000 gallons per day per well, which becomes contaminated during the process. Initially<br />
hydrofracturing one horizontal Marcellus well may use from two to nine million gallons of water, and<br />
additional hydrofracturing may occur over the productive life of the well (five to 25 years or more) (The<br />
Pennsylvania State University, 2009b).<br />
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