Hydraulic fracturing can be described as being the fracturing of a rock by a pressurized liquid. Certain veins or dikes form naturally. The simulation is usually conducted once in the life of the well and greatly enhances fluid removal and well productivity, but there has been an increasing trend towards multiple hydraulic fracturing as production declines. According to ProPublica hydraulic fracturing “is a process used in nine out of ten natural gas wells in the United States, where millions of gallons of water, sand and chemicals are pumped underground to break apart the rock and release gas. Scientists are worried that the chemicals used in fracturing may pose a threat either underground or when waste fluids are handled and sometimes spilled on the surface.

To give more explanations, “hydraulic fracturing is a technique used relatively briefly during the well completion process. It often takes place a mile or more below groundwater supplies. Shale rock has gas trapped in pores smaller than the width of a hair, so we must create a network of small fissures in the rock to release the gas. This involves injecting a mixture of 90 percent water, 9.5  percent sand, and 0.5 percent chemicals (that in part prevents bacterial growth and reduce friction) into the well at high pressures to keep the fissures open, which allows the gas to flow. Again, the activity is continuously monitored. Experts monitor data such as injection pressure and flow rates during the process to ensure that everything is going according to the plan.”

According to an article posted on June 17th, 2011 by Ken Cohen called “Facts on the hydraulic process” it is proven that the hydraulic fracturing – “a method that’s enabling greater production of natural gas in shale and other formation – poses no more risk to the environment or water supplies than any other oil and gas production technique.”  Whats most important about “tracking” is ensuring that proper well design and water-handling procedures are rigorously applied at every well. ” The finding is just the latest confirmation of what the U.S. Ground Water Protection Council and others have found in their studies of hydraulic fracturing: ‘Taken together, state and federal requirements, along with the technologies and practices developed by industry, serve to protect human health and help reduce environmental impacts from shale gas operations,” the Ground Water Protection Council said in a primer prepared for the Department of Energy in 2009’

Sources

http://www.exxonmobilperspectives.com/2011/06/17/facts-hydraulic-fracturing-process/?gclid=CIWl7Jyr27wCFfM7OgodxkEAAw&gclsrc=aw.ds

http://www.propublica.org/special/hydraulic-fracturing-national

http://en.wikipedia.org/wiki/Hydraulic_fracturing