Tuesday, March 15, 2011

What is hydrofracking?

The process of hydraulic fracturing of shale to release natural gas is not new. It has been used in some form since the late 70s. However, the newest incarnation of hydrofracking employs a horizontal fracturing method that allows gas to be harvested from previously unproductive areas such as the Barnett Shale in Texas and the Marcellus Shale along the east coast and Midwest. The video below gives an excellent description of the process. Basically, water mixed with particulate matter (usually sand) and additional chemicals used to assist fracturing are pumped at extremely high pressure into a horizontally-drilled hole in the shale. The pressurized water creates thousands of cracks in the shale, and the particulate keeps the cracks open to allow the gas to escape and be harvested. The water and residual particulate are pumped back out of the well, and the gas can then be harvested. (Hydraulic Fracturing, geology.com) The link here is for an interactive representation of how hydrofracking works, as well as the environmental risks involved at each step.

Environmental concerns arise because the fractures in the shale may extend into sources of drinking water, contaminating the drinking water with radiation and harmful chemicals. Another issue is that the water retrieved from the gas wells must be treated or recycled, and very few water treatment facilities are equipped to treat radiation in  water. As a result, potentially dangerous water is being dumped into rivers and streams, allowing for further contamination of drinking water and negative impact on wildlife. (Urbina, 2011)

Hydrofracking Overview

Works Cited
Hydraulic Fracturing of Oil & Gas Wells Drilled in Shale. (n.d.). Geology.com - Earth Science News, Maps, Dictionary, Articles, Jobs. Retrieved March 15, 2011, from http://geology.com/articles/hydraulic-fracturing/

URBINA, I. (2011, February 26). Regulation Lax as Gas Wells€™ Tainted Water Hits Rivers - NYTimes.com. The New York Times - Breaking News, World News & Multimedia. Retrieved March 8, 2011, from http://www.nytimes.com/2011/02/27/us/27gas.html?_r=3&scp=5&sq=natural%20gas

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