Page 296 - Fundamentals of Enhanced Oil and Gas Recovery

284 Mohammad Ali Ahmadi

shale gas has become economical through the application of hydraulic fracturing tech-
nologies [66]. Sovacool [67] argues that many people are opposed to shale gas because
of various environmental and sustainability issues associated with shale gas production
through the use of hydraulic fracturing technology. Mair et al. [68] maintain that in
many circumstances, the environmental costs followed by the shale gas production
dominates the economic benefits, comprising groundwater and drinking water con-
tamination, greenhouse gas emissions, and earthquakes. As a result, shale gas has been
banned in some European countries, notably, France and Bulgaria [63]. The main aim
of this section is to discuss environmental issues following shale gas production using
hydraulic fracturing method and to provide some recommendations for solving these
issues or minimizing the consequences of these problems on the human life. From an
environmental position, three main categories such as air emissions, water issues, and
land problems should be taken into account for studying environmental impacts of
shale gas production using the hydraulic fracturing method.

9.4.1 Air Emissions

A statement regarding the amount of shale gas contribution to global warming and
climate change is an uncertain comment, which needs more research [69 72].
However, the most frequent recommendation is replacing shale gas to coal for power
generation; this replacement could decrease greenhouse gases emissions [63]. An addi-
tional air emission issue in shale gas development is photochemical oxidants creation
potential (POCP), which is also known as photochemical smog. Compared to other
energy technologies, shale gas has a greater POCP: up to 45 times bigger than
nuclear power, 26 times larger than offshore wind, and three times higher than solar
PV [63]. Different air contaminants are produced during the shale gas production,
comprising nitrogen oxides (NO x ), volatile organic compounds, alkenes, alkanes, and
silica particles [63].

9.4.2 Impacts to Water
One of the main conflicts of interests in shale gas production is significant water con-
sumption, which will increase stress on water supplies, mainly in semiarid and arid
regions [73 76]. However, as explained in Laurenzi and Jersey [77], in comparison
with conventional oil, oil sands, and coal, the water footprint of shale gas is lower
[63]. As described before, fracturing fluid that is used for hydraulic fracturing process
comprises water, sand, and different chemicals. These chemical additives that are uti-
lized in fracturing fluid are mainly surfactants, polymers, and biocides (Biocides:
“Additive applied to kill bacteria in the water” [63]). Moore et al. [78] maintain that
using these chemical agents in fracturing fluid are a source of concern for the public
owing to possible contamination of water sources [63]. Vengosh et al. [79] demon-
strate three main ways for water pollution exposure including stray gas; spills, leaks,