What is hydraulic fracturing (hydrofracking)

Drillers create artificial fractures in shale to release natural gas, predominately using a method called hydraulic fracturing. During hydraulic fracturing well operators inject a mixture of water and chemicals – about two to nine million gallons of water with chemicals making up about one to five percent of the total volume – into wells at extremely high pressure to crack and prop open the shale. The degree of risk posed by the chemicals in fracturing and drilling fluids depends on their concentrations and the nature of exposure.

Drillers create artificial fractures in shale to release natural gas, predominately using a method called hydraulic fracturing. During hydraulic fracturing well operators inject a mixture of water and chemicals – about two to nine million gallons of water with chemicals making up about one to five percent of the total volume – into wells at extremely high pressure to crack and prop open the shale. The degree of risk posed by the chemicals in fracturing and drilling fluids depends on their concentrations and the nature of exposure.

Drillers prefer horizontal wells over vertical wells in the Marcellus Shale for multiple reasons. First, horizontal wells provide a better return on investment. Although horizontal wells cost approximately 80 percent more than vertical wells, they are nearly 400 percent more productive. Additionally, horizontal wells allow drillers to receive the maximum benefit from natural fractures in the Marcellus Shale. Drillers intersect more natural fractures when drilling horizontally, compared to drilling vertically, because most of the existing fractures are orientated vertically in the Marcellus Shale. Out of the total drilling permits applications the DEC received in 2007, about 10 percent were for horizontal wells.

The DEC released a draft assessment on potential risks from the use of horizontal drilling and high-volume hydraulic fracturing in the New York region of the Marcellus Shale on Sept. 30. This draft assessment includes proposed measures to ensure safe operations and mitigate environmental impacts from this type of drilling. The DEC has set an effective moratorium on the issuance of drilling permits utilizing these methods of extraction in the Marcellus Shale until the completion of the public comment period, scheduled to end Dec. 31.

“There’s this huge ecological gem that is about to get industrialized,” said Wes Gillingham, Catskill Mountainkeeper program director. “This is probably one of the biggest landscape changes that the East has seen in a really long time.”