What is Marcellus Shale?
What Is Marcellus Shale?
The Marcellus Shale is a natural gas field formation, which spans across parts of Pennsylvania, New York, Ohio, and West Virginia. Extending over 575 miles and having a thickness of up to 900 feet, the Marcellus Shale has the potential to hold anywhere from 1.9 to 516 trillion cubic feet of natural gas.
Recent advances in natural gas extraction methods, namely, horizontal drilling and hydraulic fracturing, have made the development of the Marcellus Shale possible. Although providing huge economic payoffs, the actual drilling process has many concerned over the potential for adverse environmental and human health risks. Currently, New York is deliberating whether to proceed with these drilling procedures within certain parts of the state. Horizontal drilling involves drilling a horizontal well down vertically to a depth above the target gas bearing rock formation, the a hole is drilled horizontally to reach into the gas bearing rock up to 10,000 feet below the earth’s surface. Once the horizontal well is drilled the process of hydraulic fracturing is used. Hydraulic fracturing technique involves the injection of more than a million gallons of water, sand, and chemicals at high pressure down and across into the horizontally drilled wells. The pressurized mixture works to cause the rock layer to crack. The cracks are then held open by the sand particles so that natural gas from the shale can flow up the well. The amount of water pumped into an individual well can be as much as 5 million gallons
The major concern of this contamination of the underground sources of drinking water is the hydraulic fluids and additives that are used in the process of hydraulic fracturing. These different chemicals added to the fracturing fluids, have the potential risk of contaminating underground sources of drinking water which would lead to health risks to humans if consumed. The fracturing fluids used in the Marcellus Shale are water based or mixed slick water fracturing fluids. Slick water fracturing fluids are water based fluids mixed with friction reducing additives, the main component being petroleum distillates. The addition of friction reducers allows a fracturing fluid and proppant to be pumped to the target zone at a higher rate and reduced pressure than by using water alone. Petroleum distillates that are added consist of BTEX chemicals such as benzene, toluene, ethylbenzene, and xylene, which the EPA has concluded that all of these substances are toxic in water at very low levels. There are many other chemical additives in the fracturing fluid, but many of these additives are not disclosed by gas drilling companies, citing because of trade secrets. Extensive drilling at the Marcellus Shale has already taken place in Pennsylvania for almost four years now, and evidence by residents living around the areas where there are drilling wells have noticed a decline in the quality of their drinking water.
The risk associated with drilling operation concerns various aspect like the geography of NY, infrastructure and the actual drilling process. The geology of New York (NY) is such that the Marcellus Shale formation lies beneath all or part of 29 counties, including the entire NYC West of Hudson watershed. NY is one of the few states where the water supply runs untreated through hundreds of miles of pipelines. About 18,000 square miles of the watershed overlays the Marcellus shale and any disturbances in this region due to drilling would cost billions of dollars to clean it up and might even outweigh the expected profit. Serious financial concern is that residents will continue to pay water tax, as they have in the past, theywill now be paying for water that could potentially be incorporated ridden with toxic and carcinogenic chemicals. Also, if well drilling does occur near the Catskill watershed, and the water supply does become contaminated with toxic chemicals, a filtration system may need to be put into place to protect the residents of the city. A filtration system for a water supply of this magnitude could cost upwards of $10 billion, and most likely will be funded by taxpayers.
Another issue at hand is the capacity for water treatment facilities to treat wastewater from the fracturing process. The proposed facilities to be used by drilling companies cannot assure that all contaminants from the fracture fluid can be removed before the water is emptied to the environment. Air pollution is another potential environmental and economical risk that can cost more resources to deal with than economical benefits of gas sales. Since heavy construction equipment is used in the gas development are operated on diesel fuel therefore the serious risk of the air pollution of the state will occur.
Air pollution effects from mobile sources are well known and extremely injurious to the human and environment and overcome this problem additional technological advancement is required. The risks in land corrosion, soil contamination and overall threat to ecosystem are additional problems on top of the water and air pollution; consequently, persistent ignorance of the environment in New York State will lead to the negative consequences in the future. As a possible outcome of the gas development of the Marcellus shale, could be an increase in chronic respiratory and cardiovascular diseases among local population around the drilling wells as well as major cities like New York.
Credit:
Following Article is a brief review of the RISK ASSESSMENT PROJECT that was presented in St. John’s University during TOX EXPO 2010. This project was done by Amie Dooley, Martina Efeyini, Trudi Denoon, Aishwarya Sarma, Rohan Nagavally, Ramya Iyer, Lavon Brown, Gregory Sarris, Vincent Marsh, Angela Aliberti, Monica Caraballo and Oleksiy Sparavalo.
Reference:
Picture 1 Energy industryPhotos.com http://www.energyindustryphotos.com/what_is_hydraulic_fracturing.htm
Picture 2, 2010 Pro Publica Inc. http://www.propublica.org/special/hydraulic-fracturing-national
Picture 3. worldpolicy.org/wordpress/2009/04/20/jodi-liss-an-end-to-the-resource-curse
Picture 4 On Earth website by Shannon Weiner, http://www.onearth.org/node/1588
Bibliography:
Pelley, J. (2003). Does hydraulic fracturing harm groundwater? Environ Sci Technol37, 11A 12A. (M.E)
Stutz Bruce. “A controversial Drilling Practice hits Roadbloak in New York City.” 25th March, 2010.
“Marcellus Shale”. Department of Environmental Conservation.10.Apr,2010. http://www.dec.ny.gov/energy/46288.html.(V.M)
J. Daniel Arthur, P.E., ALL Consulting; Brian Bohm, P.G., ALL Consulting; Mark Layne, Ph.D., P.E., ALL Consulting. “Hydraulic Fracturing Considerations of Natural Gas Wells of theMarcellusShale.
