Repository for Oil and Gas Energy Research (ROGER)

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As natural gas becomes increasingly important in our daily life, studies have been carried out on trace elements such as mercury and arsenic within it. Other than those, the existence of radioactive gaseous radon from the combustion of natural gas indoors can cause severe diseases and damages to body organs, putting a hazardous impact on human health. At the same time, the radon can also corrode gas production and transportation equipment. A review of the literature on radon concentrations in natural gas produced from gas reservoirs in China and other countries have been studied. Radon is a decay product from 238U, which is closely related to the accumulation and migration of organic matter during diagenesis. Gas recovered from reservoirs with higher than average natural 238U contains higher than average levels of 222Rn. Massive fault systems and fracture zones appear to play a significant role in radon concentrations in natural gas.

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Dramatic increases in the development of oil and natural gas from shale formations will result in large quantities of drill cuttings, flowback water, and produced water. These organic-rich shale gas formations often contain elevated concentrations of naturally occurring radioactive materials (NORM), such as uranium, thorium, and radium. Production of oil and gas from these formations will also lead to the development of technologically enhanced NORM (TENORM) in production equipment. Disposal of these potentially radium-bearing materials in municipal solid waste (MSW) landfills could release radon to the atmosphere. Risk analyses of disposal of radium-bearing TENORM in MSW landfills sponsored by the Department of Energy did not consider the effect of landfill gas (LFG) generation or LFG control systems on radon emissions. Simulation of radon emissions from landfills with LFG generation indicates that LFG generation can significantly increase radon emissions relative to emissions without LFG generation, where the radon emissions are largely controlled by vapor-phase diffusion. Although the operation of LFG control systems at landfills with radon source materials can result in point-source atmospheric radon plumes, the LFG control systems tend to reduce overall radon emissions by reducing advective gas flow through the landfill surface, and increasing the radon residence time in the subsurface, thus allowing more time for radon to decay. In some of the disposal scenarios considered, the radon flux from the landfill and off-site atmospheric activities exceed levels that would be allowed for radon emissions from uranium mill tailings. Implications: Increased development of hydrocarbons from organic-rich shale formations has raised public concern that wastes from these activities containing naturally occurring radioactive materials, particularly radium, may be disposed in municipal solid waste landfills and endanger public health by releasing radon to the atmosphere. This paper analyses the processes by which radon may be emitted from a landfill to the atmosphere. The analyses indicate that landfill gas generation can significantly increase radon emissions, but that the actual level of radon emissions depend on the place of the waste, construction of the landfill cover, and nature of the landfill gas control system.

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Community health nurses (CHNs) have an opportunity and responsibility to address potential environmental health issues related to shale drilling, even in the face of scientific uncertainty. Potential health impacts to air and water quality related to shale drilling are addressed within the context of the CHNs role of educator, case finder, advocate and researcher. Since 2005, an estimated 5,500 unconventional natural gas wells have been drilled in Pennsylvania's Marcellus Shale (Pennsylvania Department of Environmental Protection [PA DEP], n.d.), resulting in tremendous controversy throughout the state regarding impacts to human health and the environment. Although there are numerous anecdotal reports of illnesses in humans and animals living in drilling areas, there is a notable lack of peer-reviewed research on the impacts. Research efforts are underway to study these issues, including a proposed retrospective study of hospital and clinic data by Geisinger Health System's Weis Center for Research (Begos, 2012). However, CHNs have the opportunity and the responsibility to help address potential environmental health issues related to shale drilling, even in the face of scientific uncertainty. This responsibility is highlighted by the American Nurses Association's (ANA) (2003, p. 2) adoption of the Precautionary Principle, which states that "when an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically." CHN practice includes the promotion and preservation of health, and the prevention of disease, as well as assisting people in their response to illness (Maurer & Smith, 2009). In Pennsylvania's Marcellus Shale regions, CHNs must assume the critical nursing roles of educator, case finder, advocate and researcher when addressing the health needs in shale drilling communities. Unfortunately, CHNs practicing within these regions may feel unprepared to take on these roles related to unconventional gas extraction. The following discusses these CHN roles in the context of environmental health impacts of shale drilling on air and water quality.

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Improvements in technology have made it profitable to tap unconventional gas reservoirs in relatively impermeable shale and sandstone deposits, which are spread throughout the U.S., mostly in rural areas. Proponents of gas drilling point to the activity's local economic benefits yet no empirical studies have systematically documented the magnitude or distribution of economic gains. I estimate these gains for counties in Colorado, Texas, and Wyoming, three states where natural gas production expanded substantially since the late 1990s. I find that a large increase in the value of gas production caused modest increases in employment, wage and salary income, and median household income. The results suggest that each million dollars in gas production created 2.35 jobs in the county of production, which led to an annualized increase in employment that was 1.5% of the pre-boom level for the average gas boom county. Comparisons show that ex-ante estimates of the number of jobs created by developing the Fayetteville and Marcellus shale gas formations may have been too large.

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This article highlights the multi-disciplinary nature of multiple fractured horizontal wells in unconventional oil and gas reservoirs. The drilling, geomechanics, reservoir, completion, fracture stimulation, and field execution/operations disciplines must all do their jobs effectively in order to achieve success. Failure in any one discipline likely means project failure. The critical importance of multi-disciplinary success is clearest when you look at the competing objectives of horizontal well fracturing. All of the disciplines can and should work together to develop a horizontal well(s) project objective based on economics, deliverability, and/or estimated ultimate recovery; however, the geomechanics of the project will have a strong impact on whether the project objectives are achieved. The geomechanics need to be considered with respect to the stress state and its impact on hoop stresses and breakdown pressures (critically important to the drilling, completion, and fracture stimulation disciplines). Fracture interference must be considered to determine its impact on fracture width and treating pressure (critically important to the completions, fracture stimulation, and operational disciplines). In addition, the geomechanical effects on the fracture stimulation design and ultimately fracture geometry must be considered when stimulating a transverse horizontal well. From a fracture design perspective, material sourcing of the fracturing fluid (gel or treated water) is primarily a geomechanical issue in unconventional reservoirs, as is the type, size, and concentration of the proppant to be used. Even the designed fluid and proppant volumes should be based on the unconventional reservoir's rock and geomechanical considerations. This article will review some of the multidisciplinary inputs and objectives for multiple fractured transverse horizontal wells in unconventional oil and gas reservoirs. The paper will establish horizontal well fracturing design fundamentals and objectives that include determination of reservoir permeability, geomechanical parameters such as the in-situ stress state, the geomechanical basis of fracture design, and material sourcing. More importantly, this paper shows how rock and geomechanical considerations including fluid and proppant type and volumes can be utilized to design fracture stimulations in unconventional oil and gas reservoirs.

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Between November 2009 and September 2011, temporary seismographs deployed under the EarthScope USArray program were situated on a 70-km grid covering the Barnett Shale in Texas, recording data that allowed sensing and locating regional earthquakes with magnitudes 1.5 and larger. I analyzed these data and located 67 earthquakes, more than eight times as many as reported by the National Earthquake Information Center. All 24 of the most reliably located epicenters occurred in eight groups within 3.2 km of one or more injection wells. These included wells near Dallas-Fort Worth and Cleburne, Texas, where earthquakes near injection wells were reported by the media in 2008 and 2009, as well as wells in six other locations, including several where no earthquakes have been reported previously. This suggests injection-triggered earthquakes are more common than is generally recognized. All the wells nearest to the earthquake groups reported maximum monthly injection rates exceeding 150,000 barrels of water per month (24,000 m(3)/mo) since October 2006. However, while 9 of 27 such wells in Johnson County were near earthquakes, elsewhere no earthquakes occurred near wells with similar injection rates. A plausible hypothesis to explain these observations is that injection only triggers earthquakes if injected fluids reach and relieve friction on a suitably oriented, nearby fault that is experiencing regional tectonic stress. Testing this hypothesis would require identifying geographic regions where there is interpreted subsurface structure information available to determine whether there are faults near seismically active and seismically quiescent injection wells.

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Increased drilling in urban areas overlying shale formations and its potential impact on human health through decreased air quality make it important to estimate the contribution of oil and gas activities to photochemical smog. Flares and compressor engines used in natural gas operations, for example, are large sources not only of NOx but also offormaldehyde, a hazardous air pollutant and powerful ozone precursor We used a neighborhood scale (200 m horizontal resolution) three-dimensional (3D) air dispersion model with an appropriate chemical mechanism to simulate ozone formation in the vicinity ofa hypothetical natural gas processing facility, based on accepted estimates of both regular and nonroutine emissions. The model predicts that, under average midday conditions in June, regular emissions mostly associated with compressor engines may increase ambient ozone in the Barnett Shale by more than 3 ppb beginning at about 2 km downwind of the facility, assuming there are no other major sources of ozone precursors. Flare volumes of 100,000 cubic meters per hour ofnatural gas over a period of 2 hr can also add over 3 ppb to peak 1-hr ozone somewhatfurther (>8 km) downwind, once dilution overcomes ozone titration and inhibition by large flare emissions of NOx. The additional peak ozone from the hypothetical flare can briefly exceed 10 ppb about 16 km downwind. The enhancements of ambient ozone predicted by the model are significant, given that ozone control strategy widths are of the order of a few parts per billion. Degrading the horizontal resolution of the model to 1 km spuriously enhances the simulated ozone increases by reducing the effectiveness of ozone inhibition and titration due to artificial plume dilution.

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In recent years, shale gas formations have become economically viable through the use of horizontal drilling and hydraulic fracturing. These techniques carry potential environmental risk due to their high water use and substantial risk for water pollution. Using probability bounds analysis, we assessed the likelihood of water contamination from natural gas extraction in the Marcellus Shale. Probability bounds analysis is well suited when data are sparse and parameters highly uncertain. The study model identified five pathways of water contamination: transportation spills, well casing leaks, leaks through fractured rock, drilling site discharge, and wastewater disposal. Probability boxes were generated for each pathway. The potential contamination risk and epistemic uncertainty associated with hydraulic fracturing wastewater disposal was several orders of magnitude larger than the other pathways. Even in a best-case scenario, it was very likely that an individual well would release at least 200 m³ of contaminated fluids. Because the total number of wells in the Marcellus Shale region could range into the tens of thousands, this substantial potential risk suggested that additional steps be taken to reduce the potential for contaminated fluid leaks. To reduce the considerable epistemic uncertainty, more data should be collected on the ability of industrial and municipal wastewater treatment facilities to remove contaminants from used hydraulic fracturing fluid.

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This article presents an overview of the Marcellus Shale gas well drilling project in northeast Pennsylvania and serves as a model for how nurses can evaluate such problems in their own communities. Resources to help nurses become involved in the environmental health advocacy process are made available.

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What significance will developments in shale gas production have for European gas prices? Some commentators paint a gloomy picture of the future gas markets. But most forecasts for the oil market are positive. Consequently, a view appears to prevail that price trends will differ sharply between oil and gas markets. This article looks at developments in US shale gas production and discusses their impact on the movement of European gas prices. The relationship between oil and gas prices over time is also analysed.

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The debate surrounding the safety of shale gas development in the Appalachian Basin has generated increased awareness of drinking water quality in rural communities. Concerns include the potential for migration of stray gas, metal-rich formation brines, and hydraulic fracturing and/or flowback fluids to drinking water aquifers. A critical question common to these environmental risks is the hydraulic connectivity between the shale gas formations and the overlying shallow drinking water aquifers. We present geochemical evidence from northeastern Pennsylvania showing that pathways, unrelated to recent drilling activities, exist in some locations between deep underlying formations and shallow drinking water aquifers. Integration of chemical data (Br, Cl, Na, Ba, Sr, and Li) and isotopic ratios (87Sr/86Sr, 2H/H, 18O/16O, and 228Ra/226Ra) from this and previous studies in 426 shallow groundwater samples and 83 northern Appalachian brine samples suggest that mixing relationships between shallow ground water and a deep formation brine causes groundwater salinization in some locations. The strong geochemical fingerprint in the salinized (Cl > 20 mg/L) groundwater sampled from the Alluvium, Catskill, and Lock Haven aquifers suggests possible migration of Marcellus brine through naturally occurring pathways. The occurrences of saline water do not correlate with the location of shale-gas wells and are consistent with reported data before rapid shale-gas development in the region; however, the presence of these fluids suggests conductive pathways and specific geostructural and/or hydrodynamic regimes in northeastern Pennsylvania that are at increased risk for contamination of shallow drinking water resources, particularly by fugitive gases, because of natural hydraulic connections to deeper formations.

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In April 2011, we published the first comprehensive analysis of greenhouse gas (GHG) emissions from shale gas obtained by hydraulic fracturing, with a focus on methane emissions. Our analysis was challenged by Cathles et al. (2012). Here, we respond to those criticisms. We stand by our approach and findings. The latest EPA estimate for methane emissions from shale gas falls within the range of our estimates but not those of Cathles et al. which are substantially lower. Cathles et al. believe the focus should be just on electricity generation, and the global warming potential of methane should be considered only on a 100-year time scale. Our analysis covered both electricity (30% of US usage) and heat generation (the largest usage), and we evaluated both 20- and 100-year integrated time frames for methane. Both time frames are important, but the decadal scale is critical, given the urgent need to avoid climate-system tipping points. Using all available information and the latest climate science, we conclude that for most uses, the GHG footprint of shale gas is greater than that of other fossil fuels on time scales of up to 100 years. When used to generate electricity, the shale-gas footprint is still significantly greater than that of coal at decadal time scales but is less at the century scale. We reiterate our conclusion from our April 2011 paper that shale gas is not a suitable bridge fuel for the 21st Century.

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Natural gas is widely considered to be an environmentally cleaner fuel than coal because it does not produce detrimental by-products such as sulfur, mercury, ash and particulates and because it provides twice the energy per unit of weight with half the carbon footprint during combustion. These points are not in dispute. However, in their recent publication in Climatic Change Letters, Howarth et al. (2011) report that their life-cycle evaluation of shale gas drilling suggests that shale gas has a larger GHG footprint than coal and that this larger footprint “undercuts the logic of its use as a bridging fuel over the coming decades”. We argue here that their analysis is seriously flawed in that they significantly overestimate the fugitive emissions associated with unconventional gas extraction, undervalue the contribution of “green technologies” to reducing those emissions to a level approaching that of conventional gas, base their comparison between gas and coal on heat rather than electricity generation (almost the sole use of coal), and assume a time interval over which to compute the relative climate impact of gas compared to coal that does not capture the contrast between the long residence time of CO2 and the short residence time of methane in the atmosphere. High leakage rates, a short methane GWP, and comparison in terms of heat content are the inappropriate bases upon which Howarth et al. ground their claim that gas could be twice as bad as coal in its greenhouse impact. Using more reasonable leakage rates and bases of comparison, shale gas has a GHG footprint that is half and perhaps a third that of coal.

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We examined the efficacy of multiple biocides that are commonly used to control sulfate-reducing bacteria in fracturing fluids in shale natural gas formations. Seven biocides (tetrakis [hydroxymethyl] phosphonium sulfate, sodium hypochlorite, didecyldimethylammonium chloride, tri-n-butyl tetradecyl phosphonium chloride, glutaraldehyde, a glutaraldehyde and alkyldimethylbenzylammonium chloride blend, and a glutaraldehyde alkyldimethylethylbenzylammonium chloride blend) were examined. Minimum inhibitory concentrations (MIC) were determined using planktonic cells and biofilms of Desulfovibrio desulfuricans strain G20 and a sulfate-reducing enrichment culture that was obtained from a Barnett Shale frac pond. All biocides had higher MIC values for biofilms compared to planktonic cells from these two cultures. Higher concentrations of all biocides, except didecyldimethylammonium chloride, were required to kill planktonic cells of G20 that were exposed to humic acid. These results clearly indicate that biofilm formation by sulfate-reducing bacteria, as well as organic loading rates, negatively impact the efficacy of biocides. This work provides valuable information concerning the effects of biofilm formation and organic loading on biocide MIC values. These MIC data can be used as a guide for the control of microbial growth in future frac jobs, which should result in fewer incidences of sulfide production and corrosion in shale natural gas wells. (C) 2012 Elsevier Ltd. All rights reserved.

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Natural gas is widely considered to be the crucial “bridging fuel” in the transition to the low-carbon energy systems necessary to mitigate climate change. This paper develops a case study of the shale gas industry in British Columbia (BC), Canada to evaluate this assumption. We find that the transition fuel argument for gas development in BC is unsubstantiated by the best available evidence. Emissions factors for shale gas and LNG remain poorly characterized and contested in the academic literature, and context-specific factors have significant impacts on the lifecycle emissions of shale gas but have not been evaluated. Moreover, while the province has attempted to frame natural gas development within its ambitious climate change policy, this framing misrepresents substantive policy on gas production. The “transition fuel” and “climate solution” labels applied to development by the BC provincial government risk legitimizing carbon-intensive gas development. We argue that policy makers in BC and beyond should abandon the “transition fuel” characterization of natural gas. Instead, decision making about natural gas development should proceed through transparent engagement with the best available evidence to ensure that natural gas lives up to its best potential in supporting a transition to a low-carbon energy system.

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Mass balance principles were applied to a four-compartment partition model for 12 different hazardous components of hydraulic fracturing fluid additives used in 47 completed natural gas wells in the Marcellus Shale. Spill scenarios were modeled as if 1000 gallons of diluted additive were discharged into a surface water body or onto soil. Resulting concentrations were ranked according to magnitude, providing a relative comparison of quantities to be expected in each compartment. Highest mass concentrations in the water, soil and biota compartments were due to sodium hydroxide, 4,4-dimethyl oxazolidine, and hydrochloric acid. 4,4-dimethyl oxazolidine ranked highest in the air compartment.

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This article describes a place and people undergoing rapid transition using some of the preliminary findings from two years of ongoing ethnographic field work. Through exploring what ethnographic evidence is revealing concerning the impacts of Marcellus shale gas development in Bradford County, in Northeastern Pennsylvania, I illustrate the ways that rapid social and economic change processes are impacting daily lives and community dynamics in one traditionally agricultural and rural place. I provide a broad overview of the social history and current social dynamics in order to understand the significance of the short-term changes agricultural landowners and other local residents have witnessed and experienced. I discuss some of the most significant short-term changes in quality of life as seen by a small group of agricultural landowners, in relation to the cultural significance of place, home, and family, and what this tells us about the sociocultural and psychological impacts of rapid energy development. Finally, I comment on what my ethnographic data show so far with regard to the short- and long-term individual and collective impacts being experienced in this one community.

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Concerns have arisen recently as to whether the upstream oil and gas (UOG) sector — responsible for exploration, production, and some processing of raw fossil fuels — is negatively impacting human (and environmental) health in northeast British Columbia (NEBC). The region has experienced increased rates of cancers and other illnesses that have been linked to the contaminants and stressors associated with UOG. Contaminants reach human receptors through environmental pathways, namely air, soil, water, and food. Each contaminant or stressor has specific sources, transport, exposure mechanisms, and biochemistry; and each can impact health both directly and indirectly. Of particular concern are airborne sulphur and nitrogen oxides, hazardous volatile organic compounds, hydrogen sulphide, ozone, noise, and radiation; as well as soil- or water-borne hydrocarbons, heavy metals, and radiation — some of which can also impact human health through food pathways. It has been determined that UOG is negatively impacting human health in NEBC; however, further information, such as environmental monitoring, is required before the actual health risks and impacts posed by UOG can be quantified.

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The global warming impact of substituting natural gas for coal and oil is currently in debate. We address this question here by comparing the reduction of greenhouse warming that would result from substituting gas for coal and some oil to the reduction which could be achieved by instead substituting zero carbon energy sources. We show that substitution of natural gas reduces global warming by 40% of that which could be attained by the substitution of zero carbon energy sources. At methane leakage rates that are $1% of produc- tion, which is similar to today’s probable leakage rate of $1.5% of production, the 40% benefit is realized as gas substitution occurs. For short transitions the leakage rate must be more than 10 to 15% of production for gas substitution not to reduce warming, and for longer transitions the leakage must be much greater. But even if the leakage was so high that the substitution was not of immediate benefit, the 40%-of-zero-carbon benefit would be realized shortly after methane emissions ceased because methane is removed quickly from the atmosphere whereas CO2 is not. The benefits of substitution are unaffected by heat exchange to the ocean. CO2 emissions are the key to anthropogenic climate change, and substituting gas reduces them by 40% of that possible by conversion to zero carbon energy sources. Gas substitution also reduces the rate at which zero carbon energy sources must eventually be introduced.

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The recent increase in the production of natural gas from shale deposits has significantly changed energy outlooks in both the US and world. Shale gas may have important climate benefits if it displaces more carbon-intensive oil or coal, but recent attention has discussed the potential for upstream methane emissions to counteract this reduced combustion greenhouse gas emissions. We examine six recent studies to produce a Monte Carlo uncertainty analysis of the carbon footprint of both shale and conventional natural gas production. The results show that the most likely upstream carbon footprints of these types of natural gas production are largely similar, with overlapping 95% uncertainty ranges of 11.0?21.0 g CO2e/MJLHV for shale gas and 12.4?19.5 g CO2e/MJLHV for conventional gas. However, because this upstream footprint represents less than 25% of the total carbon footprint of gas, the efficiency of producing heat, electricity, transportation services, or other function is of equal or greater importance when identifying emission reduction opportunities. Better data are needed to reduce the uncertainty in natural gas?s carbon footprint, but understanding system-level climate impacts of shale gas, through shifts in national and global energy markets, may be more important and requires more detailed energy and economic systems assessments.

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The study determined the impact of gas flaring on lung function by specifically evaluating changes in Peak Expiratory Flow Rate (PEFR) of residents in Ugberikoko, a gas flaring community. Participants for the study were drawn from the representative group in the gas flaring community in Delta State, Nigeria and values obtained were compared with those from non gas flaring community (Irhodo). Peak Expiratory Flow Rate (PEFR) was measured and used to assess lung function of the selected participants (n = 400) each for both. The peak expiratory flow rate was determined using the (Wright peak flow metre as a spirometric device ) results obtained for children, young adults and older adults from the gas flaring community are 270.05±3.30 (13-17 years), 222.17±6.03 (18-30 years) and 245.00±8.66 (41-50 years), respectively. Age-matched values from nongas flaring community are 432.05±5.57 (13-17 years), 420.75±16.22 (18-30 years) and 428.57±19.41 (41-50 years). Differences in matched values were significant (p<0.05). The findings showed that residents in gas flaring community had reduced peak expiratory flow rate.

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Technological advances (e.g. directional drilling, hydraulic fracturing), have led to increases in unconventional natural gas development (NGD), raising questions about health impacts. OBJECTIVES: We estimated health risks for exposures to air emissions from a NGD project in Garfield County, Colorado with the objective of supporting risk prevention recommendations in a health impact assessment (HIA). METHODS: We used EPA guidance to estimate chronic and subchronic non-cancer hazard indices and cancer risks from exposure to hydrocarbons for two populations: (1) residents living >½ mile from wells and (2) residents living ≤ ½ mile from wells. RESULTS: Residents living ≤ ½ mile from wells are at greater risk for health effects from NGD than are residents living >½ mile from wells. Subchronic exposures to air pollutants during well completion activities present the greatest potential for health effects. The subchronic non-cancer hazard index (HI) of 5 for residents ≤ ½ mile from wells was driven primarily by exposure to trimethylbenzenes, xylenes, and aliphatic hydrocarbons. Chronic HIs were 1 and 0.4. for residents ≤ ½ mile from wells and >½ mile from wells, respectively. Cumulative cancer risks were 10 in a million and 6 in a million for residents living ≤ ½ mile and >½ mile from wells, respectively, with benzene as the major contributor to the risk. CONCLUSIONS: Risk assessment can be used in HIAs to direct health risk prevention strategies. Risk management approaches should focus on reducing exposures to emissions during well completions. These preliminary results indicate that health effects resulting from air emissions during unconventional NGD warrant further study. Prospective studies should focus on health effects associated with air pollution.

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Worldwide shale-gas development has the potential to cause substantial landscape disturbance. The northeastern U.S., specifically the Allegheny Plateau in Pennsylvania, West Virginia, Ohio, and Kentucky, is experiencing rapid exploration. Using Pennsylvania as a proxy for regional development across the Plateau, we examine land cover change due to shale-gas exploration, with emphasis on forest fragmentation. Pennsylvania’s shale-gas development is greatest on private land, and is dominated by pads with 1–2 wells; less than 10 % of pads have five wells or more. Approximately 45–62 % of pads occur on agricultural land and 38–54 % in forest land (many in core forest on private land). Development of permits granted as of June 3, 2011, would convert at least 644–1072 ha of agricultural land and 536–894 ha of forest land. Agricultural land conversion suggests that drilling is somewhat competing with food production. Accounting for existing pads and development of all permits would result in at least 649 km of new road, which, along with pipelines, would fragment forest cover. The Susquehanna River basin (feeding the Chesapeake Bay), is most developed, with 885 pads (26 % in core forest); permit data suggests the basin will experience continued heavy development. The intensity of core forest disturbance, where many headwater streams occur, suggests that such streams should become a focus of aquatic monitoring. Given the intense development on private lands, we believe a regional strategy is needed to help guide infrastructure development, so that habitat loss, farmland conversion, and the risk to waterways are better managed.

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The growing interdependence of the nation's electricity and natural gas systems presents challenges to the reliable and efficient operation of both systems. Shale gas developments, retirement of aging fossil units, and increases in variable renewable generation are likely to increase the prominence of natural-gas-fired generation and interdependence risks. The authors review factors at the intersection of electricity and natural gas markets and operations, and present ways to address the risks.

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Following the “gas revolution” occurring in the USA, where shale gas is contributing to abundant and low-priced domestic gas production, many companies and countries all around the world are considering investing in this type of gas source. Key elements of shale gas production include the extensive drilling campaign, the need for hydraulic fracturing (with its implication on the whole water supply/handling cycle) and the realisation of a continuously growing network of geographically scattered production facilities and flowlines, which accompany gas from wellheads to the final customers. Exporting shale gas experience from the USA to new promising basins will not simply mean customising subsurface technologies (such as drilling & completion or hydraulic fracturing) to a geologically different area; it will especially imply adopting an unconventional mindset for surface facilities. First of all, there may not be a context as fertile as in the USA in terms of existing infrastructures (pipelines, treatment plants) or abundance of local contractors/providers, therefore an efficient engineering and fast-response procurement and construction chain will be more crucial for life-cycle-cost minimization than it is for conventional gas production. Moreover, standardized and repeatable production facilities will likely be the most economically viable way to handle gas flow from hundreds or thousands of wells, designed in parallel with step-by-step territorial studies to locate those facilities considering geographical, infrastructural and legislative constraints and opportunities. Finally, the passage from exploration to extensive commercial production will likely require a proper appraisal campaign through a pilot development, especially in new areas, with the objective to “long-test” shale gas wells performances and optimize full-development approaches in an environmentally friendly way.

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Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse gas emissions in the process. However, there has also been confusion about the climate implications of increased use of natural gas for electric power and transportation. We propose and illustrate the use of technology warming potentials as a robust and transparent way to compare the cumulative radiative forcing created by alternative technologies fueled by natural gas and oil or coal by using the best available estimates of greenhouse gas emissions from each fuel cycle (i.e., production, transportation and use). We find that a shift to compressed natural gas vehicles from gasoline or diesel vehicles leads to greater radiative forcing of the climate for 80 or 280 yr, respectively, before beginning to produce benefits. Compressed natural gas vehicles could produce climate benefits on all time frames if the well-to-wheels CH4 leakage were capped at a level 45–70% below current estimates. By contrast, using natural gas instead of coal for electric power plants can reduce radiative forcing immediately, and reducing CH4 losses from the production and transportation of natural gas would produce even greater benefits. There is a need for the natural gas industry and science community to help obtain better emissions data and for increased efforts to reduce methane leakage in order to minimize the climate footprint of natural gas.

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Carbon capture and geological sequestration is the only available technology that both allows continued use of fossil fuels in the power sector and reduces significantly the associated CO2 emissions. Geological sequestration requires a deep permeable geological formation into which captured CO2 can be injected, and an overlying impermeable formation, called a caprock, that keeps the buoyant CO2 within the injection formation. Shale formations typically have very low permeability and are considered to be good caprock formations. Production of natural gas from shale and other tight formations involves fracturing the shale with the explicit objective to greatly increase the permeability of the shale. As such, shale gas production is in direct conflict with the use of shale formations as a caprock barrier to CO2 migration. We have examined the locations in the United States where deep saline aquifers, suitable for CO2 sequestration, exist, as well as the locations of gas production from shale and other tight formations. While estimated sequestration capacity for CO2 sequestration in deep saline aquifers is large, up to 80% of that capacity has areal overlap with potential shale-gas production regions and, therefore, could be adversely affected by shale and tight gas production. Analysis of stationary sources of CO2 shows a similar effect: about two-thirds of the total emissions from these sources are located within 20 miles of a deep saline aquifer, but shale and tight gas production could affect up to 85% of these sources. These analyses indicate that colocation of deep saline aquifers with shale and tight gas production could significantly affect the sequestration capacity for CCS operations. This suggests that a more comprehensive management strategy for subsurface resource utilization should be developed.

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Background: The Marcellus Shale is a vast natural gas field underlying parts of Pennsylvania, New York, West Virginia, Virginia, and Maryland. Rapid development of this field has been enabled by advances in hydrofracking techniques that include injection of chemical and physical agents deep underground. Response to public concern about potential adverse environmental and health impacts has led to the formation of state and national advisory committees., Objectives: We review the extent to which advisory committees formed in 2011 by President Obama and governors of the states of Maryland and Pennsylvania contain individuals with expertise pertinent to human environmental public health. We also analyze the extent to which human health issues are of concern to the public by reviewing presentations at the public meeting of the Secretary of Energy Advisory Board (SEAB) Natural Gas Subcommittee formed by the U.S. President’s directive., Results: At a public hearing held by the SEAB Natural Gas Subcommittee 62.7% of those not in favor of drilling mentioned health issues. Although public health is specified to be a concern in the executive orders forming these three advisory committees, we could identify no individuals with health expertise among the 52 members of the Pennsylvania Governor’s Marcellus Shale Advisory Commission, the Maryland Marcellus Shale Safe Drilling Initiative Advisory Commission, or the SEAB Natural Gas Subcommittee., Conclusions: Despite recognition of the environmental public health concerns related to drilling in the Marcellus Shale, neither state nor national advisory committees selected to respond to these concerns contained recognizable environmental public health expertise.

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Shale-gas production using hydraulic fracturing of mostly horizontal wells has led to considerable controversy over water-resource and environmental impacts. The study objective was to quantify net water use for shale-gas production using data from Texas, which is the dominant producer of shale gas in the U.S. with a focus on three major plays: the Barnett Shale (similar to 15 000 wells, mid-2011), Texas-Haynesville Shale (390 wells), and Eagle Ford Shale (1040 wells). Past water use was estimated from well-completion data, and future water use was extrapolated from past water use constrained by shale-gas resources. Cumulative water use in the Barnett totaled 145 Mm(3) (2000-mid-2011). Annual water use represents similar to 9% of water use in Dallas (population 1.3 million). Water use in younger (2008-mid-2011) plays, although less (6.5 Mm(3) Texas-Haynesville, 18 Mm(3) Eagle Ford), is increasing rapidly. Water use for shale gas is <1% of statewide water withdrawals; however, local impacts vary with water availability and competing demands. Projections of cumulative net water use during the next 50 years in all shale plays total similar to 4350 Mm(3), peaking at 145 Mm(3) in the mid-2020s and decreasing to 23 Mm(3) in 2060. Current freshwater use may shift to brackish water to reduce competition with other users.

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CO2 emissions from the US power sector decreased by 8.76% in 2009 relative to 2008 contributing to a decrease over this period of 6.59% in overall US emissions of greenhouse gases. An econometric model, tuned to data reported for regional generation of US electricity, is used to diagnose factors responsible for the 2009 decrease. More than half of the reduction is attributed to a shift from generation of power using coal to gas driven by a recent decrease in gas prices in response to the increase in production from shale. An important result of the model is that, when the cost differential for generation using gas rather than coal falls below 2-3 cents/kWh, less efficient coal fired plants are displaced by more efficient natural gas combined cycle (NGCC) generation alternatives. Costs for generation using NGCC decreased by close to 4 cents/kWh in 2009 relative to 2008 ensuring that generation of electricity using gas was competitive with coal in 2009 in contrast to the situation in 2008 when gas prices were much higher. A modest price on carbon could contribute to additional switching from coal to gas with further savings in CO2 emissions.

Abstract:
Oil and gas firms are utilizing a controversial drilling technique, hydraulic fracturing, or fracking, to access unconventional natural gas reserves in Pennsylvania's Marcellus Shale. The potential impacts of fracking are creating sharp tensions between stakeholders over the costs and benefits of drilling within their communities. In particular, much contention has emerged over water resources as the process both uses and degrades billions of gallons of water. This paper takes a critical look at the way multi-scale neoliberal discourses obfuscate comprehensive understandings of fracking's effect on water resources. We turn to the neoliberal environments literature as a way to situate the economic logic that normalizes the impacts of fracking on resources, particularly in the absence of an effective regulatory framework. We argue that neoliberal pro-fracking arguments are (re)defining the relationship among people, the environment, and institutions, which in turn normalizes the impacts on communities and the resources on which they depend.

Abstract:
Identifying the source of stray gas in drinking water supplies principally relies on comparing the gas composition in affected water supplies with gas samples collected in shows while drilling, produced gases, casing head gases, pipeline gases, and other potential point sources. However, transport dynamics of free and dissolved gas migration in groundwater aquifers can modify both the concentration and the composition of point source stray gases flowing to aquifers and occurring in the groundwater environment. Accordingly, baseline and forensic investigations related to stray gas sources need to address the effects of mixing, dilution, and oxidation reactions in the context of regional and local hydrology. Understanding and interpreting such effects are best addressed by collecting and analyzing multiple samples from baseline groundwater investigations, potential point sources, and impacted water resources. Several case studies presented here illustrate examples of the natural variability in gas composition and concentration data evident when multiple samples are collected from produced gases, casing head gases, and baseline groundwater investigations. Results show that analyses of single samples from either potential contaminant point sources or groundwater and surface water resources may not always be sufficient to document site-specific baseline conditions. Results also demonstrate the need to consistently sample and analyze a variety of baseline groundwater and gas composition screening parameters. A multidisciplinary approach is the best practice for differentiating among the effects of fluid and gas mixing, dilution, and natural attenuation.

Abstract:
Shale gas resources are relatively plentiful in the United States and in many countries and regions around the world. Development of these resources is moving ahead amidst concerns regarding environmental risks, especially to water resources. The complex nature of this distributed extractive industry, combined with limited impact data, makes establishing possible effects and designing appropriate regulatory responses challenging. Here we move beyond the project level impact assessment approach to use regional collective impact analysis in order to assess a subset of potential water management policy options. Specifically, we examine hypothetical water withdrawals for hydraulic fracturing and the subsequent treatment of wastewater that could be returned or produced from future active shale gas wells in the currently undeveloped Susquehanna River Basin region of New York. Our results indicate that proposed water withdrawal management strategies may not provide greater environmental protection than simpler approaches. We suggest a strategy that maximizes protectiveness while reducing regulatory complexity. For wastewater treatment, we show that the Susquehanna River Basin region of New York State has limited capacity to treat wastewater using extant municipal infrastructure. We suggest that modest private investment in industrial treatment facilities can achieve treatment goals without putting public systems at risk. We conclude that regulation of deterministic water resource impacts of shale gas extraction should be approached on a regional, collective basis, and suggest that water resource management objectives can be met by balancing the need for development with environmental considerations and regulatory constraints.

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An overview is given of the mechanisms and processes (viscous flow, diffusion, sorption, desorption) affecting transport in unconventional reservoir rocks. Processes are described, terms and definitions are given, and selected literature data are presented to document the state of knowledge and the data situation on gas, water and two-phase flow in low-permeable lithotypes. Gas transport in the matrix of shales and coals is controlled by and may be restricted to diffusion. Depending on the gas type (e.g. methane or carbon dioxide), transport may be strongly affected by sorption. In many instances, high capillary threshold pressures prevent gas from moving as a continuous phase through the conducting pore network. In contrast, tight sandstone reservoir rocks allow for capillary-controlled viscous flow of a gas phase. Because in these rocks the determination of the water saturation at the prevailing flow conditions is difficult or impossible, we propose to directly use the relationship between effective gas permeability and capillary pressure for the description of two-phase (gas/water) flow in these rocks. In ongoing studies this relationship is being studied systematically for both, steady state and non-steady state saturation conditions.

Abstract:
To manage America’s 991,479 km2 (245 million acres) of public BLM lands for such mixed uses as natural resource extraction, wildlife, and recreation requires knowledge about effects of habitat alterations. Two of North America’s largest natural gas fields occur in the southern region of the Greater Yellowstone Ecosystem (Wyoming), an area that contains >100,000 wintering ungulates. During a 5-year period (2005–2009), we concentrated on patterns of habitat selection of pronghorn (Antilocapra americana) to understand how winter weather and increasing habitat loss due to gas field development impact habitat selection. Since this population is held below a food ceiling (i.e., carrying capacity) by human harvest, we expected few habitat constraints on animal movements – hence we examined fine-scale habitat use in relationship to progressive energy footprints. We used mixed-effects resource selection function models on 125 GPS-collared female pronghorn, and analyzed a comprehensive set of factors that included habitat (e.g., slope, plant cover type) and variables examining the impact of gas field infrastructure and human activity (e.g., distance to nearest road and well pad, amount of habitat loss due to conversion to a road or well pad) inside gas fields. Our RSF models demonstrate: (1) a fivefold sequential decrease in habitat patches predicted to be of high use and (2) sequential fine-scale abandonment by pronghorn of areas with the greatest habitat loss and greatest industrial footprint. The ability to detect behavioral impacts may be a better sentinel and earlier warning for burgeoning impacts of resource extraction on wildlife populations than studies focused solely on demography. Nevertheless disentangling cause and effect through the use of behavior warrants further investigation.

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This paper will make the case that the unconventional natural gas business is not the same as the conventional natural gas business. The skills involved in finding, developing and producing discreet pools of oil and gas are not identical to those for shale gas projects. However, they are similar enough that many companies large and small have not recognized this difference and have not changed their business models. Those companies are struggling to succeed. Others have become huge successes seemingly overnight. This paper is based primarily on our experience as a junior oil and gas start-up company with three different shale gas plays, as well as my observations as President of one of the first junior companies in Canada to become involved in shale gas. Our first shale gas play was the Liard Basin Besa River shale play in northeast British Columbia in western Canada. We tried conventional approaches, with the usual business model, and failed. Worse, we had to go back to the beginning of the learning curve and start over. More recently we have applied the new technical methods in our Utica shale gas play in Quebec in eastern Canada with great technical success. However, other “orders of magnitude” factors required for success have stalled our progress as we struggle with acquiring new skills in public policy and politics. Based on these experiences, it is our belief that geology and sound science still matters now more than ever. It is our position that new skills and approaches are needed in areas that have not been the traditional strengths of our industry.

Abstract:
Conventional thinking just ten years ago was that the United States would become a major importer of liquefied natural gas. Yet, today the discussion has shifted to one of export potential, largely driven by the rapid development of shale gas resources. This has had dramatic implications not only for the US, but also for the rest of the world. In particular, the outlook for several gas exporting countries has been substantially altered. Namely, while the US has certainly from an energy security standpoint, Russia, Iran, Venezuela and Qatar have seen their projected fortunes reduced. Development of shale gas has effectively increased the global elasticity of supply and could substantially reduce overall dependence on exports from these critical countries.

Abstract:
The UK’s first well to encounter shale gas was drilled into the Upper Jurassic Kimmeridge Clay in 1875, but its significance was not realised at the time. 25 years ago research at Imperial College applied the US shale gas paradigm to evaluate the UK’s shale gas potential. Shale sequences with potential for gas production were identified in Carboniferous strata in the Midlands, and in Jurassic strata, particularly in the Weald. Without encouragement from Her Majesty’s Government no exploration resulted from this initial research. Publication of the results of the project was rejected by many UK journals. It was finally published in the USA in 1987. Subsequent evaluations of UK petroleum resources by the Department of Energy and its descendants published in 2001 and 2003 omitted any mention of shale gas resources. Recent timely re-evaluations of the UK’s shale gas potential have been carried out by the British Geological Survey and the Department for Energy & Climate Change. In 2008 the 13th Round of Onshore Licensing resulted in the award of several blocks for shale gas exploration, though bids were often based on a quest for both shale gas and conventional prospects. Cuadrilla Resource’s Preese Hall No. 1 well drilled in 2010 was the first well drilled to specifically test for UK shale gas. The same drilling and fracturing techniques that led to the shale gas renaissance in the USA are now being applied to extracting oil from organic-rich shales that are currently in the oil window. It is interesting to speculate that oil may be produced by such techniques from the thermally mature Jurassic shales in the Wessex and Weald basins in the southern UK.

Abstract:
The multispecies analysis of daily air samples collected at the NOAA Boulder Atmospheric Observatory (BAO) in Weld County in northeastern Colorado since 2007 shows highly correlated alkane enhancements caused by a regionally distributed mix of sources in the Denver-Julesburg Basin. To further characterize the emissions of methane and non-methane hydrocarbons (propane, n-butane, i-pentane, n-pentane and benzene) around BAO, a pilot study involving automobile-based surveys was carried out during the summer of 2008. A mix of venting emissions (leaks) of raw natural gas and flashing emissions from condensate storage tanks can explain the alkane ratios we observe in air masses impacted by oil and gas operations in northeastern Colorado. Using the WRAP Phase III inventory of total volatile organic compound (VOC) emissions from oil and gas exploration, production and processing, together with flashing and venting emission speciation profiles provided by State agencies or the oil and gas industry, we derive a range of bottom-up speciated emissions for Weld County in 2008. We use the observed ambient molar ratios and flashing and venting emissions data to calculate top-down scenarios for the amount of natural gas leaked to the atmosphere and the associated methane and non-methane emissions. Our analysis suggests that the emissions of the species we measured are most likely underestimated in current inventories and that the uncertainties attached to these estimates can be as high as a factor of two.

Abstract:
A transition from the global system of coal-based electricity generation to low-greenhouse-gas-emission energy technologies is required to mitigate climate change in the long term. The use of current infrastructure to build this new low-emission system necessitates additional emissions of greenhouse gases, and the coal-based infrastructure will continue to emit substantial amounts of greenhouse gases as it is phased out. Furthermore, ocean thermal inertia delays the climate benefits of emissions reductions. By constructing a quantitative model of energy system transitions that includes life-cycle emissions and the central physics of greenhouse warming, we estimate the global warming expected to occur as a result of build-outs of new energy technologies ranging from 100 GW e to 10 TW e in size and 1–100 yr in duration. We show that rapid deployment of low-emission energy systems can do little to diminish the climate impacts in the first half of this century. Conservation, wind, solar, nuclear power, and possibly carbon capture and storage appear to be able to achieve substantial climate benefits in the second half of this century; however, natural gas cannot.

Abstract:
The Haynesville shale in Louisiana is one of several unconventional gas plays that have been discovered in the U.S. in the past decade and promise to dramatically change the course of future energy development given its enormous resource potential. Unconventional gas resources are abundant, but their development is particularly sensitive to technologic risk, geologic uncertainty, and gas price. To produce at commercial rates, shale gas wells require horizontal drilling and hydraulic fracturing which significantly increases the capital cost. The purpose of this paper is to examine the price sensitivity of Haynesville wells and the economic viability of the play. We characterize the operating envelope under which Haynesville wells are economic and describe the profit space based on a review of production and cost characteristics. The majority of Haynesville wells fail to break-even on a full-cycle basis at prevailing gas prices. This harsh economic reality will control future activity after new entrants fulfill their drilling requirements. For $5/Mcf gas, the average Haynesville well is expected to generate a 10% return when drilling and completion costs are $7 million and operating expenditures are $1/Mcf. We explore two-variable factor models using type curves and introduce functional relations for the multiple variable case.

Abstract:
Unconventional gas resources in the U.S. are abundant, but their development is capital intensive and subject to technologic risk, geologic uncertainty, and gas price volatility. In the Haynesville shale, wells are characterized by high initial production rates and rapid decline, and it is the tradeoff between these conditions and high investment that define the profitability of the play. The purpose of this paper is to examine the economic viability and sustainability of the Haynesville shale play. We characterize the operating envelope under which Haynesville wells are economic and describe the profit space based on a technical review of production and cost characteristics in the region. We explore two-variable factor models using type curves and construct before and after tax functional relationships. The majority of Haynesville wells fail to break-even on a full-cycle basis at prevailing gas prices. For $6/Mcf gas, average producers are expected to generate pre-tax returns between 1 and 11.5% for 1 to $0.5/Mcf operating expenses and $7.5 million capital expenditure. P10 wells are expected to generate a pre-tax return of 52 to 25% for $7.5 to $10 million capital expenditures and post-tax returns of 40 to 20%. We show that gas prices in the first year of production are an important determinant of well profitability.

Abstract:
The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas.

Abstract:
Synopsis: As North America's energy demands grow in the face of diminishing conventional fossil...

Abstract:
Shale gas is a new energy resource that has shifted the dominant paradigm on U.S. hydrocarbon resources. Some have argued that shale gas will play an important role in reducing greenhouse gas emissions by displacing coal used for electricity, serving as a moderate-carbon "bridge fuel." Others have questioned whether methane emissions from shale gas extraction lead to higher greenhouse gas emissions overall. I argue that the main impact of shale gas on climate change is neither the reduced emissions from fuel substitution nor the greenhouse gas footprint of natural gas itself, but rather the competition between abundant, low-cost gas and low-carbon technologies, including renewables and carbon capture and storage. This might be remedied if the gas industry joins forces with environmental groups, providing a counterbalance to the coal lobby, and ultimately eliminating the conventional use of coal in the United States.

Abstract:
Environmental concerns surrounding drilling for gas are intense due to expansion of shale gas drilling operations. Controversy surrounding the impact of drilling on air and water quality has pitted industry and lease-holders against individuals and groups concerned with environmental protection and public health. Because animals often are exposed continually to air, soil, and groundwater and have more frequent reproductive cycles, animals can be used as sentinels to monitor impacts to human health. This study involved interviews with animal owners who live near gas drilling operations. The findings illustrate which aspects of the drilling process may lead to health problems and suggest modifications that would lessen but not eliminate impacts. Complete evidence regarding health impacts of gas drilling cannot be obtained due to incomplete testing and disclosure of chemicals, and nondisclosure agreements. Without rigorous scientific studies, the gas drilling boom sweeping the world will remain an uncontrolled health experiment on an enormous scale.