Page 408 - Fundamentals of Gas Shale Reservoirs

388 GAS SHALE ENVIRONMENTAL ISSUES AND CHALLENGES

costs, as natural gas can be a less expensive fuel option than geological characteristics; climatic conditions; the use by
diesel, providing potential cost savings for the industry and companies of new technologies and best practices; and
for energy consumers. With its foray into dual‐fuel tech- regulatory and enforcement activities. In a report issued in
nology, Cabot joins the likes of Apache Corporation, which December 2012, the GAO noted that because shale
in January became the first energy exploration and produc- development is relatively new in some areas, the long‐term
tion company to power a full hydraulic fracturing operation effects—after operators are to have restored portions of the
using natural gas‐burning engines at its Granite Wash oper- land to pre‐development conditions—have not been evalu-
ations in Oklahoma. By switching to natural gas, Apache ated (GAO, 2012). Without this data, the cumulative effects
said it expects to reduce fuel costs by roughly 60%, while of shale oil and gas development on habitat and wildlife are
also lowering emissions. largely unknown. GAO also found that, in general, shale gas
development impacts can vary significantly even within
specific shale basins.
18.7 SOCIAL IMPACTS ON SHALE GAS In response to growing community concerns about the
COMMUNITIES impact of shale gas development, on July 11, 2014, the
American Petroleum Institute has issued ANSI‐API Bulletin
While many communities have embraced shale gas 100‐3, which sets forth detailed recommendations for oil and
development for its economic benefits, there is recognition gas companies seeking to engage with the communities
of the need to understand the potential negative impacts affected by exploration and development activities (American
shale gas development can have on communities in produc- Petroleum Institute, 2014). The standards came 1 week after
tion areas. These impacts can include: New York ruled its towns and cities could ban fracking. Other
states including California and Colorado have also pushed
(i) increased demands on local infrastructure and util- for bans on drilling and hydraulic fracturing.
ities including a severe strain on roads due to
increased truck traffic (including accidents and
congestion); 18.8 INDUCED SEISMICITY: WASTEWATER
(ii) the “Boom Town” effects of rapid population INJECTION AND EARTHQUAKES
growth such as inadequate educational and medical As part of its ongoing effort to study a variety of potential
facilities and other social services, housing short- impacts of U.S. energy production, United States Geological
ages or lack of affordable housing, and increased Survey (USGS) scientists have been investigating the recent
crime; increase in the number of magnitude 3 and greater earth-
(iii) potential effects on human health due to water con- quakes in the midcontinent of the United States (Ellsworth
tamination, noise level increase, and poor air quality et al., 2012). The largest of these was a magnitude 5.6 event
from the emissions associated with fracking in central Oklahoma that destroyed 14 homes and injured
operations; two people. The mechanism responsible for inducing these
(iv) the physical footprint of drill pads, roads, storage events appears to be the well‐understood process of weak-
sites, truck traffic, compressors, and rigs in fracking ening a preexisting fault by elevating the fluid pressure. The
areas; and fact that the disposal (injection) of wastewater produced
(v) habitat fragmentation, particularly in and around while extracting resources has the potential to cause earth-
recreational areas, and the disturbance of vegetation quakes has long been known. One of the earliest documented
and soils that are disturbed where gas wells require case histories with a scientific consensus of wastewater
new roads, clearing, and leveling. inducing earthquakes is at the Rocky Mountain Arsenal well,
near Denver. There, a large volume of wastewater was
Community concerns about these impacts are reflected injected from 1962 to 1966, inducing a series of earthquakes
in survey studies in the areas of Pennsylvania that are in below magnitude 5.
the early Marcellus boom stages (Brasier et al., 2011). Beginning in 2001, the average number of earthquakes
Respondents were most concerned about the impact on the occurring per year of magnitude 3 or greater increased sig-
local economy; social relations; and aesthetics, amenities, nificantly, culminating in a six‐fold increase in 2011 over
and environmental quality. The potential for road damage twentieth century levels. The scientists then began taking a
as a result of the heavy traffic from drilling trucks carrying closer look at earthquake rates in regions where energy pro-
equipment was another impact that was mentioned duction activities have changed in recent years. The lead
repeatedly. researcher in the paper, Mr. Ellsworth, believes the increased
The degree of surface impacts can be affected by many number of earthquakes is not associated with hydraulic frac-
factors, such as the location and the rate of development; turing, but instead with the disposal of drilling waste fluids