Water Quality and Quantity Impacts of Hydraulic Fracturing
Curr Sustainable Renewable Energy Rep
Water Quality and Quantity Impacts of Hydraulic Fracturing
Yusuke Kuwayama 0 1
Sheila Olmstead 0 1
Alan Krupnick 0 1
0 S. Olmstead LBJ School of Public Affairs, University of Texas at Austin , P.O. Box Y, E2700, Austin, TX 78713 , USA
1 Y. Kuwayama (
The academic literature has lagged both industry and public opinion in measuring and characterizing potential water quantity and quality concerns related to hydraulic fracturing (fracking). However, the science behind fracking's water impacts experienced its own boom during the 2010s. In this paper, we address this critical emerging environmental and energy issue, providing an overview of the current state of knowledge, with a particular focus on academic journal articles that have been published in the past five years. These studies have generally found that the water quantity impacts of shale gas and tight oil development are, on average, not significantly worse than for their conventional counterparts, though the specific location and timing of withdrawals for energy development matter. On the other hand, recent findings also suggest that the water quality concerns associated with fracking may be more serious than water quantity concerns.
Shale gas; Unconventional gas; Tight oil; Unconventional oil; Hydraulic fracturing; Surface water; Groundwater; Water quality; Water scarcity
Introduction
The production of crude oil and natural gas from
unconventional reservoirs has expanded dramatically in recent years,
particularly in the United States. U.S. production of natural
gas from deep shale formations in particular is projected to
continue accelerating through 2040, supplying both the U.S.
and foreign markets; U.S. domestic oil production from shale
is expected to grow through 2020 and then level off [
1
].
Exploitation of these resources has been facilitated by
advances in several technologies, including hydraulic fracturing,
directional drilling, and seismic imaging. The first of these
technologies, hydraulic fracturing (fracking), has raised
concerns over potential impacts on water resources, as fracked
wells are thought to require more water per unit of energy
produced than conventional wells, and the chemicals added
to the water and pumped underground with high pressure can
be damaging to the environment. While public concerns over
groundwater and surface water pollution have grown over
time, the academic literature has lagged in measuring and
characterizing potential water quantity and quality concerns
related to fracking.
In the past four years, however, the science of fracking’s
water impacts has experienced its own boom. This
paper addresses this critical emerging environmental and
energy issue, providing an overview of the current state
of knowledge, most of which thus far has come from
study sites in the U.S., where the energy industry and
associated manufacturing sectors have been transformed
by fracking and the resulting abundance of accessible
domestic oil and gas. We focus on the impacts from production of
unconventional oil and gas and do not discuss the impacts of
their consumption (e.g., in electricity generation or
transportation) on water resources, because these impacts would be
similar whether energy production were from conventional or
unconventional sources.
Description of Shale gas, Tight oil, and Hydraulic
Fracturing
Shale gas is methane and related gases that occur in fractures
and pore spaces between individual mineral grains of
lowpermeability shale formations, or that can be adsorbed onto
minerals or organic matter within shale rock. Tight oil,
sometimes referred to as “shale oil” (not to be confused with oil
shale), is similarly found in shale, but can also be produced
from other sedimentary rock such as siltstone and sandstone.
The presence of these fossil fuel resources within
lowpermeability formations requires horizontal drilling and
hydraulic fracturing to make their exploitation economically
feasible. Though both technologies have a relatively long
history—fracking was used commercially in the oil and gas
industry as early as 1950, and horizontal wells were common by the
late 1970s [
2
]—innovations in these technologies have driven
the recent boom.
Wells for shale gas and tight oil are first drilled vertically,
and then turned horizontally to follow the oil- or gas-bearing
formation, significantly increasing the surface area of the
wellbore exposed to the formation. Multiple lateral wells are
typically drilled from a given well pad. Hydraulic fracturing
involves injecting water, sand, and chemical additives (such as
scale inhibitors, friction reducers, and biocides) into the
wellbore at very high pressure so as to create small fractures
in the formation and prop open pathways for hydrocarbons to
flow out of the well once the pressure is removed.
Shale gas production in the United States grew from about
1 trillion cubic feet (tcf) in 2006 to about 9.7 tcf in 2012, and i (...truncated)