Background:
The idea about hydraulic fracturing is to maximize the output of the well by pumping fluids to hundreds to thousands of feet under the ground. The resources that are usually expected include the following four:
- oil
- water
- natural gas
- geothermal energy
Due to the increased internal pressure caused by the fluids pumped underground, the resources can come out more easily after the the fracturing is done.
Method:
The liquid is made up 98 to 99.5 percent of water and sand. Some chemical additives are added depending on the individual well.
A hole is needed to be drilled, the depth is depended on where the liquids is being pumped to. A steel pipe would be inserted to transmit the liquids. After a while, the region, where the liquid is injected, is saturated with the fluid and the formation is cracked due to the pressure.
Then the resources coming out from the well will be flowing more easily.
Side Effect:
Fracturing may cause water contamination and pollution, including dust, noise, etc.
However, in 2004, the United States Environmental Protection Agency (EPA) posted a study of the possibility of environmental threats due to fracking. The result said there was little or no contamination.
Reference:
http://fracfocus.org/hydraulic-fracturing-how-it-works/hydraulic-fracturing-process
http://en.wikipedia.org/wiki/Hydraulic_fracturing
http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/wells_hydrowhat.cfm