ALL Consulting has put together a good piece on fracturing.

"The issue of hydraulic fracturing has raised many concerns from the public as well as government officials. This paper will review the history and evolution of hydraulic fracturing, including environmental and regulatory considerations. Additionally, technical and environmental considerations will be presented applicable to hydraulic fracturing in the unconventional arena of gas shales with an emphasis on the Marcellus Shale of the Appalachians. Topics addressed in the paper will include discussion on why hydraulic fracturing is performed; the hydraulic fracturing process; applicable design and engineering aspects of well completions; geological considerations such as confinement of the fracturing process; potential risks to groundwater and underground sources of drinking water; and the use of hydraulic fracturing fluids and associated technical considerations."

To read the entire document go HERE.