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Enhanced Oil Recovery (EOR) in Shale Oil Reservoirs 285

and illegal dumping/disposal; and accumulation in disposal locations. However, inves-
tigating the connection between shale gas production and contaminating water is
inconclusive [63,80 84].

9.4.3 Impacts to Land
Productions from Shale gas reservoirs have various effects to land including land usage,
terrestrial ecotoxicity [85 87], and earthquakes; however, the effect of shale gas pro-
duction on earthquakes is an unclear question. Same as other oil and gas wells,
whether conventional or unconventional, to initiate drilling of the well an area of
land needs to be prepared to place the drilling rig and allow access to the drilling
location [63]. A further land impact related to shale gas production is terrestrial eco-
toxicity, mainly owing to the discarding of the drilling waste, which comprises toxic
materials, for instance, barite. As Johri and Zoback [88] argue, tremor can be initiated
by fractures created during hydraulic fracturing for shale gas production. However, in
comparison with those related to other activities, for instance, coal mining and reser-
voir impoundment for hydroelectric projects, the number of tremors caused by shale
gas production are much lower. Also, the magnitude of the tremor initiated by shale
gas production is usually not felt or felt with little damage. As Davies et al. [89] have
reported, shale gas production just caused three earthquakes in British Columbia
(Canada), Lancashire (United Kingdom), and Oklahoma (United States). Compared
to the tremors caused by other human activities three earthquakes is too small [63].

9.4.4 Recommendations
As Mair et al. [68] demonstrate, the best available technology (BAT) for defeating the
obstacle of air emissions from shale gas production is the use of “green” well comple-
tion, not allowing gas to be vented, and detecting and fixing leaks in tools and pipes
[63]. As Wang et al. [90] demonstrate, some strategies that can be used for eliminating
the effect of water contamination are baseline data, continuous monitoring over the
wells lifetime, and adaptive wastewater management. These strategies can decrease the
probability of chemical exposure, while chemical tracking can be utilized to detect
the source of pollution. As Rahm and Riha [91] propose, to reduce the water con-
sumption during shale gas production, different plans can be used, which include reg-
ulation for water withdrawals, using brackish water instead of freshwater, and
recycling/reuse of water [63]. As Manda et al. [92] recommend, one of the promising
methods to reduce the land usage during shale gas production is using multiwell pads,
which have a water usage per well two to four times lower than single-well pads [63].
Regardless of the uncertainties due to lack of data, some evidence associated with
shale gas production and utilization are well established. For instance, water usage,
wastewater disposal, the creation of POCP, land usage, and well leakages are the cause
of many of the environmental issues; these problems can be solved by implementing