From the U.S. Government Accountability Office, www.gao.gov

Transcript for: Water Use in Hydraulic Fracturing

Description: How water is used in the process of hydraulic fracturing.

Related GAO Work: GAO-15-545: Technology Assessment: Water in the Energy 
Sector: Reducing Freshwater Use in Hydraulic Fracturing and Thermoelectric 
Power Plant Cooling

Released: September 2015


[Image: Fish jumping in lake] Water is a limited natural resource that
plays a key role in the development of fossil fuels [Images: Coal,
natural gas, oil]. The availability of water for energy development is
critical to the economic security and prosperity of the United States.
[Image: U.S. map with dollar sign] GAO has previously found that oil and
gas development poses environmental and public health risks [Image: GAO
report cover of Oil and Gas: Information on Shale Resources,
Development, and Environmental Public Health Risks]; however, this video
specifically discusses water use in the process of hydraulic fracturing.

[Image: Tanker truck extracting water from lake under words 2-9 million
gallons of water] Hydraulic fracturing, also known as "fracking," can
use anywhere from 2 to 9 million gallons of water per well. Let's look
at how the process is designed to work and how the water is used.
Hydraulic fracturing is a process that facilitates the extraction of oil
and natural gas by allowing it to flow through shale rock formations
that are typically more than a mile below the earth's surface. [Image:
Well delivers fracking fluid 8,000 feet deep before turning horizontally
into shale bed] Once the proper permits are approved [Image: Document
stamped approved] and the site is prepared, the first step is drilling
the well. A steel casing that lines the vertical surfaces of the hole is
designed to protect underground sources of drinking water [Image: Well
and casing begin above ground and extend below aquifer].

It is common to extend this casing several hundred feet below any
aquifers. An intermediate casing is also installed, designed to prevent
fluid migration and to keep the hole from collapsing. [Image: Casing
extends 6,000 feet deep] At the end of the intermediate casing, the hole
is drilled laterally to run within the shale bed. [Image: Hole extends
and turns horizontally into shale bed] Another casing, the production
casing, is installed in the rest of the hole. [Image: Production casing
surrounds hole] Explosives are used to perforate the production casing
and start fracturing the shale [Image: Explosions create holes at end of
casing] so that the water, chemicals, and sand [Image: Three trucks pump
water, chemicals, and sand from top of well] that will be injected into
the well at high pressure can enter the shale rock formation. [Image:
Mixture speeds down well]  The mixture that is injected into the well is
mostly water.

The steadily increasing pressure of the water fractures a segment of the
shale [Image: Water creates fissures in shale outside of well] and the
sand keeps the fractures propped open once pressure is released. [Image:
Sand enters the fissure walls] The process is repeated along the entire
horizontal length of the well to maximize oil and gas recovery.

[Image: Camera pans across well and fissures] Oil or natural gas can
then travel through the fractures into the well and to the surface where
it is collected. [Images: Arrows show oil or natural gas flowing into
well up to the surface] After the fracturing process is complete, part
of the water mixture flows back to the surface within the first week or
two, along with oil and gas. [Image: Water, oil, and gas flow within
well to surface] The well can produce this water for months. [Image:
Calendar turning] The well may also produce naturally occurring brine
water. [Image: Well water turns green] The water is generally disposed
of in designated underground disposal wells. In some water-scarce
regions, well operators are now treating the water for reuse in future
hydraulic fracturing operations. [Image: Water pumped into a truck
labeled to disposal well and another labeled for reuse]

To learn more about how water is used in energy development, check out
GAO-15-545 in the Technology Assessment section of GAO.gov. [Images: GAO
technology assessment icon and text showing gao.gov and GAO-15-545]