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What is Hydraulic Fracturing a.k.a. Hydrofracking, Fracking?

Hydraulic fracturing, or “fracking,” is most often referred to as the practice of injecting a mixture of water, sand and chemicals into the ground at high pressures to fracture the rock and release natural oil and natural gas. This  2011 Congressional Report identifies the chemicals used in hydraulic fracturing. It is the most comprehensive list we know of to date.  The list includes highly toxic carcinogenic chemicals like benzene, toluene, formaldehyde and diesel fuel. See illustrated examples at What the Frack is in That Water?

The fracking process subjects enough pressure that the rocks in the productive formation fracture, or break.  The purpose of the sand is to prop open the fracture, so it stays in place.  What is unleashed from the shale itself includes methane and other hydrocarbons, salt or brine, heavy metals, and *radioactive elements. Brines originated from sea water initially incorporated in the  sediment. Subsequent compaction and chemical alteration resulted in concentration of the constituents. For comparative  purposes,  the surface water  closest in composition to these subsurface brines is that  of the present day Dead Sea, according to the Illinois EPA.

Small, low-volume, vertical, low-pressure fracking has been used in Illinois since the early 1940’s to stimulate oil wells.  High-pressure, high-volume, horizontal fracking which is now taking place in PA, TX, ND, and other states, is a relatively new combination of the technologies of horizontal drilling and fracking.  In Illinois, massive horizontal wells are now being planned which will go over a mile horizontally underground, with far greater pressures and volumes of water used (1-8 million gallons of water) per frack as opposed to “old-style” fracking.  Please see our category on North Dakota to see how this new technology combination has affected residents of that state.

* Our Illinois new Albany Shale is high in radioactivity according to this geological report

Oil and natural gas extraction from shale, in other words, the entire process of fracking, is a complex series of procedures which include:

1) Building access roads, digging centralized water and flowback holding ponds and construction of the well site itself

Landscape scarred by access roads.

2) Construction of compressor stations and above ground and underground gas pipelines

New construction on a 12 unit compressor station, Marcellus Shale, Pennsylvania

3) Drilling the well: down into the ground vertically first, and then horizontally up to a mile in the case of high volume horizontal fracking

Drill rig and associated equipment dwarfs a farm house and barn.

4) Hydraulic fracturing: sending millions of gallons of a water, chemicals and sand at extremely high pressure deep into a well bore in the earth causing shale to fracture and release natural gas. This can be done up to eighteen times.

A tangle of hydraulic fracturing pipes for pumping water and sand into the well bore at high pressure.

5) Capturing and transporting the natural gas and oil

Major U.S. Natural Gas Transportation Corridors, 2008

6) Disposal of flowback water or brine which is then disposed of in evaporation pits or injected at high pressure into disposal wells, or “deep injection wells.” There are 7843 Class II wells currently  in Illinois, according to the US EPA.

Fracking effluent pit, or brine pit.

Photo of trucks storing frackwater in Pennsylvania, courtesy of Skytruth

Class II injection well, Wise County, Texas.

The Illinois EPA regulates Class I, III, IV, and V wells in Illinois and the Illinois Department of Natural Resources regulates Class II wells. The dilemma is that Illinois IDNR admits it does not have enough people or funding to properly monitor Class II wells.


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