Repository for Oil and Gas Energy Research (ROGER)

Abstract:
The Permian Basin is one of the most prolific oil and natural gas geologic basins in the US. With soaring production in the last decade, the economic impact of oil and gas development in the basin has become a pressing policy question to answer. This paper presents the first basin-wide study that examines both the employment effect and the income effect of the Permian Basin development. We consider not only the local impact but also the spatial spillover effect and the industry-level spillover effect. To correct for the estimation bias due to the potential simultaneity between drilling decisions and economic activities, an instrumental variables (IV) regression model is proposed. We find that both the employment effect and the income effect of shale development in the basin are highly significant. We also show that there are significant spatial spillover effects and spillover effects onto the indirect industries. Relevant policy implications for the long-run economic prosperity in the Permian Basin are discussed.

Abstract:
A strong online response has marked contention on shale gas from the outset, as campaign members link across borders to share information and inform themselves about the impacts of development. In this article, we apply a post-political lens to online activity in the English shale gas debate, to determine how this complex information ecology has shaped the dynamics of protest. Using shale gas development in Lancashire, North West England, as our case study we argue that the seismic events of 2011, in combination with the Government framing of public scepticism as a matter of information deficit led to an online information divide which constrained how effectively the dominant institutional actors could engage. Between 2011 and 2017, three challenges of online information: complexity, overload and loss of gatekeepers, served to perpetuate this division. Anti-shale gas campaigners were less constrained in their activity but the substantial burden of online activism contributed towards perceptions of disempowerment, as improved information access failed to deliver policy influence. The ultimate consequence was to contribute towards the turn to direct action. Applying a post-political analysis to online activity in information-intensive issues yields valuable insights into the varied ways in which internet use may influence the expression of dissent.

Abstract:
Formulated products used in hydraulic fracturing are designed to address specific subsurface challenges during oil and gas well completion and are intended for the treatment of a myriad of issues in a wellbore; however, there are public concerns regarding the use of certain chemical ingredients in hydraulic fracturing. Public perception of hydraulic fracturing and concerns regarding water and chemical usage provide the industry with a unique opportunity to review current chemistries and water management practices with the aim being to identify more environmentally acceptable alternatives or replacements. Herein we describe what the industry considers to be the greatest challenges, what is currently being done, and potential opportunities to provide alternatives that lead to a more sustainable industry.

Abstract:
Hydraulic fracturing (fracking) operations, associated with horizontal drilling for oil/gas production, are known to induce earthquakes from fluid injection in disposal wells. In recent years, numerous studies have shown a close relationship between induced seismic activities and the high-pressure injection of wastewater, especially in Texas, Kansas, and Oklahoma. Detailed analysis of 17 major fracking locations across the USA has been carried out to study the impact of horizontal wells and the corresponding injected wastewater on earthquake activities. Earthquake data for the period 1998–2018 obtained from the USGS earthquake catalog shows an increase in frequency of earthquakes within a radius of 150 km at fracking locations, prominently in south-central USA. The stimulation of earthquakes depends on the amount of injected water in both horizontal and disposal injected wells, and the geology, hydrological, and geophysical settings nearby the drilling site. The observed seismicity increases with the number of horizontal wells in Texas (correlation R2 = 0.726) and Oklahoma (correlation R2 = 0.636) at the fracking locations.

Abstract:
Hydraulic fracturing (HF) technology is increasingly utilized for oil and gas extraction operations. The widespread use of HF has led to concerns of negative impacts on both the environment and human health. Indeed, the potential endocrine disrupting impacts of HF chemicals is one such knowledge gap. Herein, we used structure-based molecular docking to assess the binding affinities of 60 HF chemicals to the human androgen receptor (AR). Five HF chemicals had relatively high predicted AR binding affinity, suggesting the potential for endocrine disruption. We next assessed androgenic and antiandrogenic activities of these chemicals in vitro. Of the five candidate AR ligands, only Genapol®X–100 significantly modified AR transactivation. To better understand the structural effect of Genapol®X–100 on the potency of AR inhibition, we compared the antiandrogenic activity of Genapol®X–100 with that of its structurally similar chemical, Genapol®X–080. Interestingly, both Genapol®X–100 and Genapol®X–080 elicited an antagonistic effect at AR with 20% relative inhibitory concentrations of 0.43 and 0.89 μM, respectively. Furthermore, we investigated the mechanism of AR inhibition of these two chemicals in vitro, and found that both Genapol®X–100 and Genapol®X–080 inhibited AR through a noncompetitive mechanism. The effect of these two chemicals on the expression of AR responsive genes, e.g. PSA, KLK2, and AR, was also investigated. Genapol®X–100 and Genapol®X–080 altered the expression of these genes. Our findings heighten awareness of endocrine disruption by HF chemicals and provide evidence that noncompetitive antiandrogenic Genapol®X–100 could cause adverse endocrine health effects.

Abstract:
A large volume of water is required in shale gas development, especially for large-scale hydraulic fracturing in horizontal wells. This study focuses on 334 shale gas wells in the largest production field Fuling in China. Models are formulated to estimate the water use at each stage of the development process, including pre-drilling preparation, drilling and cementing, fracturing, gas testing, production testing. Domestic water used by employee community of shale gas companies are also fully considered. The results show that the average fracturing water use per well was 34,756.0 m3 in Fuling, which accounted for 98% of the total water use. By the end of 2017, the total fracturing water used in Fuling was 1.09 × 107 m3, and a total of 2.28 × 106 m3 of flowback fluid was achieved with 2.16 × 106 m3 of water reused. In addtion, the domestic water used by the employee community was found to be 2.19 × 106 m3, which was equivalent to the water saved from the flowback fluid. China’s special “development campaign” mode for shale gas extraction is the reason. The results improve the understanding of water use in China’s shale gas development and also provide important implications for water management.

Abstract:
Uranium and other radionuclides are prominent in many unconventional oil/gas shales and is a potential contaminant in flowback/produced waters due to the large volumes/types of chemicals injected into the subsurface during stimulation. To understand the stability of U before and after stimulation, a geochemical study of U speciation was carried out on three shales (Marcellus, Green River, and Barnett). Two types of samples for each shale were subjected to sequential chemical extractions: unreacted and shale reacted with synthetic hydraulic fracture fluid. A significant proportion of the total U (20-57%) was released from these three shales after reaction with fracture fluid, indicating that U is readily leachable. The total U released exceeds labile water soluble and exchangeable fractions in unreacted samples, indicating that fluids leach more recalcitrant phases in the shale. Radiographic analysis of unreacted Marcellus shale thin sections shows U associated with detrital quartz and the clay matrix in the shale. Detrital zircon and TiO2 identified by electron microprobe could account for the hotspots. This study shows that significant proportions of U in three shales are mobile upon stimulation. In addition, the extent of mobilization of U depends on the U species in these rocks.

Abstract:
Increasing reliance on natural gas for energy has resulted in expansion of the natural gas infrastructure, including pipelines and compressor stations to transport gas. Compressor stations emit numerous particulate and gaseous pollutants including volatile organic compounds (VOCs) but studies of human health in association with compressor stations are almost completely absent from the literature. The objective of the study was to test for associations between VOC emissions from compressor stations and adjusted mortality rates. We conducted a county-level ecological study, using VOC emission data from the 2017 National Emissions Inventory, 2017 age-adjusted total mortality per 100,000 population from CDC data, and covariates from the County Health Rankings data. Results of multiple linear regression models showed that total age-adjusted mortality, controlling for covariates (race/ethnicity, education, poverty, urbanicity, smoking and obesity rates), was significantly higher in association with greater non-methane VOC emissions from compressor stations. Twelve individual VOCs were also associated with significantly higher adjusted mortality. Results provide preliminary evidence that compressor stations along natural gas pipelines are sources of pollutant exposures that may contribute to adverse human health outcomes.

Abstract:
The use of hydraulic fracturing (HF) to extract oil and natural gas has increased, along with intensive discussions on the associated risks to human health. Three technical processes should be differentiated when evaluating human health risks, namely (1) drilling of the borehole, (2) hydraulic stimulation, and (3) gas or oil production. During the drilling phase, emissions such as N­ Ox, NMVOCs (non-methane volatile organic compounds) as precursors for tropospheric ozone formation, and ­SOx have been shown to be higher compared to the subsequent phases. In relation to hydraulic stimulation, the toxicity of frac fluids is of relevance. More than 1100 compounds have been identified as components. A trend is to use fewer, less hazardous and more biodegradable substances; however, the use of hydrocarbons, such as kerosene and diesel, is still allowed in the USA. Methane in drinking water is of low toxicological relevance but may indicate inadequate integrity of the gas well. There is a great concern regarding the contamination of ground- and surface water during the production phase. Water that flows to the surface from oil and gas wells, so-called ‘produced water’, represents a mixture of flow-back, the injected frac fluid returning to the surface, and the reservoir water present in natural oil and gas deposits. Among numerous hazardous compounds, produced water may contain bromide, arsenic, strontium, mercury, barium, radioactive isotopes and organic compounds, particularly benzene, toluene, ethylbenzene and xylenes (BTEX). The sewage outflow, even from specialized treatment plants, may still contain critical concentrations of barium, strontium and arsenic. Evidence suggests that the quality of groundwater and surface water may be compromised by disposal of produced water. Particularly critical is the use of produced water for watering of agricultural areas, where persistent compounds may accumulate. Air contamination can occur as a result of several HF-associated activities. In addition to BTEX, 20 HF-associated air contaminants are group 1A or 1B carcinogens according to the IARC. In the U.S., oil and gas production (including conventional production) represents the second largest source of anthropogenic methane emissions. High-quality epidemiological studies are required, especially in light of recent observations of an association between childhood leukemia and multiple myeloma in the neighborhood of oil and gas production sites. In conclusion, (1) strong evidence supports the conclusion that frac fluids can lead to local environmental contamination; (2) while changes in the chemical composition of soil, water and air are likely to occur, the increased levels are still often below threshold values for safety; (3) point source pollution due to poor maintenance of wells and pipelines can be monitored and remedied; (4) risk assessment should be based on both hazard and exposure evaluation; (5) while the concentrations of frac fluid chemicals are low, some are known carcinogens; therefore, thorough, well-designed studies are needed to assess the risk to human health with high certainty; (6) HF can represent a health risk via long-lasting contamination of soil and water, when strict safety measures are not rigorously applied.

Abstract:
Article: Air quality measurements in the western Eagle Ford Shale

Abstract:
Studies of neonatal health risks of unconventional natural gas development (UNGD) have not included comprehensive assessments of environmental chemical exposures. We investigated a clustering of dysphagic cases in neonatal foals born between 2014 and 2016 in an area of active UNGD in Pennsylvania (PA),USA. We evaluated equine biological data and environmental exposures on the affected PA farm and an unaffected New York (NY) farm owned by the same proprietor. Dams either spent their entire gestation on one farm or moved to the other farm in late gestation. Over the 21-month study period, physical examinations and blood/tissue samples were obtained from mares and foals on each farm. Grab samples of water, pasture soil and feed were collected; continuous passive sampling of air and water for polycyclic aromatic hydrocarbons was performed. Dysphagia was evaluated as a binary variable; logistic regression was used to identify risk factors. Sixty-five foals were born, 17 (all from PA farm) were dysphagic. Odds of dysphagia increased with the dam residing on the PA farm for each additional month of gestation (OR = 1.4, 95% CI 1.2, 1.7, p = 6.0E-04). Males were more likely to be born dysphagic (OR = 5.5, 95% CI 1.2, 24.5, p = 0.03) than females. Prior to installation of a water filtration/treatment system, PA water concentrations of 3,6-dimethylphenanthrene (p = 6.0E-03), fluoranthene (p = 0.03), pyrene (p = 0.02) and triphenylene (p = 0.01) exceeded those in NY water. Compared to NY farm water, no concentrations of PAHs were higher in PA following installation of the water filtration/treatment system. We provide evidence of an uncommon adverse health outcome (dysphagia) in foals born near UNGD that was eliminated in subsequent years (2017–2019) following environmental management changes. Notably, this study demonstrates that domestic large animals such as horses can serve as important sentinels for human health risks associated with UNGD activities.

Abstract:
Large amounts of fracturing flowback and wastewater with complex compositions are produced during hydraulic fracturing. Characterization of hydraulic fracturing flowback and produced water (HF-FPW) is an important initial step in efforts to determine a suitable treatment method for this type of wastewater. In the present study, fracturing flowback and produced water samples were obtained from well CN-F and well CN-E in the prophase and anaphase stages of the Changning shale gas mining area. Chemical characterization of inorganic and organic substances was then conducted. Metal contents were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), and all inorganic anions involved were determined by ion chromatography. The organic pollutant components were analyzed in detail by combining Fourier transform infrared spectrometer (FTIR) and gas chromatography-mass spectrometer (GC-MS). Results showed that samples contained salt (TDS = 30,000–50,000 mg/L), metals (e.g., 650 ± 50 mg/L calcium), and total organic carbon (TOC = 32–178 mg/L). The organic substances detected in all samples could be divided into six categories, alkanes, aromatics, halogenated hydrocarbons, alcohols, esters, and ketones. C6–C21 straight-chain alkanes and C7–C13 naphthenes had the highest amount of organic matter, reaching more than 48%. The organic matter contained fracturing fluid additives, such as surfactants (e.g., ethylene glycol), and nitrotrichloromethane, which is a chlorinated product of some additives. These results provide information on the chemical composition of HF-FPW in Sichuan, China, as well as a basis for subsequent processing.

Abstract:
The challenge of balancing biodiversity protection with economic growth is epitomized by the development of renewable and unconventional energy, whose adoption is aimed at stemming the impacts of global climate change, yet has outpaced our understanding of biodiversity impacts. We evaluated the potential conflict between biodiversity protection and future electricity generation from renewable (wind farms, run-of-river hydro) and non-renewable (shale gas) sources in British Columbia (BC), Canada using three metrics: greenhouse gas (GHG) emissions, electricity cost, and overlap between future development and conservation priorities for several fish and wildlife groups - small-bodied vertebrates, large mammals, freshwater fish – and undisturbed landscapes. Sharp trade-offs in global versus regional biodiversity conservation exist for all energy technologies, and in BC they are currently smallest for wind energy: low GHG emissions, low-moderate overlap with top conservation priorities, and competitive energy cost. GHG emissions from shale gas are 1000 times higher than those from renewable sources, and run-of-river hydro has high overlap with conservation priorities for small-bodied vertebrates. When all species groups were considered simultaneously, run-of-river hydro had moderate overlap (0.56), while shale gas and onshore wind had low overlap with top conservation priorities (0.23 and 0.24, respectively). The unintended cost of distributed energy sources for regional biodiversity suggest that trade-offs based on more diverse metrics must be incorporated into energy planning.

Abstract:
Background Hydraulic fracturing often involves the injection of millions of gallons of fracturing fluids into underground shales to extract oil and natural gas, raising health concerns over potential water contamination. Many state and federal governmental agencies rely on the third-party FracFocus online registry for disclosure of chemical ingredients in fracturing fluids, but withholding chemicals as trade secrets is common. In 2016, a new format, known as the systems approach was widely encouraged as a method of reducing withholding by decoupling disclosed chemicals from their functions, protecting against reverse-engineering of fracture fluid formulas by competitors. In this study, we assess the extent to which elevated use of the systems approach in FracFocus version 3.0 translated into greater chemical disclosure. Methods We analysed 108 137 disclosure forms submitted to FracFocus between Jan 1, 2011, and Dec 31, 2018, to estimate the effect of expanded use of the systems approach on chemical withholding. We compared the proportion of forms withholding at least one chemical ingredient across time, between approaches, and by state and drilling operator. Findings Since the 2016 expansion of the systems approach, 15 677 (82%) of systems approach forms have withheld an ingredient. 13 462 (89%) of 15 062 traditional FracFocus version 3.0 forms withheld an ingredient. In the quarter following the transition (July, to September, 2016), 1211 (93%) of 1304 traditional forms withheld an ingredient, compared with only 958 (76%) of 1262 systems approach forms. However, withholding rates increased throughout 2017 and, by 2018, 6949 (87%) of 8016 systems approach forms were withholding ingredients. At the end of our analysis period in the fourth quarter of 2018, systems approach forms had even greater withholding (903 [88%] of 1025 forms) than did traditional forms (855 [85%] of 1004 forms). We did not find that states or operators that submitted more systems approach forms had lower withholding. Interpretation The systems approach has not reduced FracFocus chemical withholding, which continues to occur in around 87% of well fracture disclosures. FracFocus might not be an appropriate substitute for regulatory action, and measures are urgently needed for environmental and public safety. Funding University of Chicago Argonne National Laboratory Seed Grant.

Abstract:
Managing produced water from oil and gas wells constitutes a significant portion of the costs of operating a well. In this work, we have designed two different centralized water treatment facilities capable of managing produced water from oil and gas wells in Texas and Louisiana, both of which convert the produced water into the following valuable resources: ten-pound brine and fresh water. The two main designs each use commercially available technology with varying levels of establishment in treating produced water. Both treatment processes remove oil and grease and suspended solids, reduce the divalent ion concentrations, and concentrate the brines to a near-saturation state. The baseline design uses chemical precipitation to remove the divalent ions to meet the reuse specifications, whereas the advanced design uses nanofiltration (NF) membranes to separate divalent ions and uses reserve osmosis (RO) membranes to partially concentrate the brine. Both models use mechanical vapor recompression to concentrate the brine up to NaCl saturation. The baseline process is shown to be cost-effective for low-hardness brines. In the case of high hardness, the chemical precipitation step is cost-prohibitive. We find that NF membranes are a promising alternative to chemical precipitation as a means of separating monovalent and divalent ions.

Abstract:
Produced water is the largest waste stream associated with oil and gas operations. This complex fluid contains petroleum hydrocarbons, heavy metals, salts, naturally occurring radioactive materials and any remaining chemical additives. In the United States, west of the 98th meridian, the federal National Pollutant Discharge Elimination System (NPDES) exemption allows release of produced water for agricultural beneficial reuse. The goal of this study was to quantify mutagenicity of a produced water NPDES release and discharge stream. We used four mutation assays in budding yeast cells that provide rate estimates for copy number variation (CNV) duplications and deletions, as well as forward and reversion point mutations. Higher mutation rates were observed at the discharge and decreased with distance downstream, which correlated with the concentrations of known carcinogens detected in the stream (e.g., benzene, radium), described in a companion study. Mutation rate increases were most prominent for CNV duplications and were higher than mutations observed in mixtures of known toxic compounds. Additionally, the samples were evaluated for acute toxicity in Daphnia magna and developmental toxicity in zebrafish. Acute toxicity was minimal, and no developmental toxicity was observed. This study illustrates that chemical analysis alone (McLaughlin et al., 2020) is insufficient for characterizing the risk of produced water NPDES releases and that a thorough evaluation of chronic toxicity is necessary to fully assess produced water for beneficial reuse.

Abstract:
The transport of natural gas through transmission and distribution networks spans 2.4 million miles of underground and above ground pipelines in the USA. This Perspective uses a critical energy justice framework to analyze Appalachian's everyday lived experiences at the frontline of energy distribution network development. The practice of installing pipelines, as well as the sheer magnitude of the pipeline system, has transformed small rural communities into industrial sites. This Perspective also adds to the emerging concept of energy justice by bringing to the forefront Appalachian residents’ voices in relation to burgeoning pipeline constructions, which are often missing from the debate on energy independence. Energy justice is based on the principle that people should not only have safe and affordable energy, but they should be protected from disproportionate negative impacts associated with generating and transmitting energy as well. Our findings are that those who reside near pipelines express fear of explosions, leaks, and negative health outcomes and are disproportionately impacted. In addition, they are concerned about regulation, state responsibility, and threats of eminent domain. We highlight how these communities are socially affected, and how residents’ daily lives are altered in inequitable ways by the construction of energy distribution networks.

Abstract:
Unconventional extraction techniques including hydraulic fracturing or “fracking” have led to a boom in oil and gas production the Eagle Ford shale play, Texas, one of the most productive regions in the United States. Nearly 400,000 people live within 5 km of an unconventional oil or gas well in this largely rural area. Flaring is associated primarily with unconventional oil wells and is an increasingly common practice in the Eagle Ford to dispose of excess gas through combustion. Flares can operate continuously for months and release hazardous air pollutants such as particulate matter and volatile organic compounds in addition to causing light and noise pollution and noxious odors. We estimated ethnic disparities in exposure to flaring using satellite observations from the Visible Infrared Imaging Spectroradiometer between March 2012-December 2016. Census blocks with majority Hispanic (>60%) populations were exposed to twice as many nightly flare events within 5 km as those with <20% Hispanics. We found that Hispanics were exposed to more flares despite being less likely than non-Hispanic White residents to live near unconventional oil and gas wells. Our findings suggest Hispanics are disproportionately exposed to flares in the Eagle Ford Shale, a pattern known as environmental injustice, which could contribute to disparities in air pollution and other nuisance exposures.

Abstract:
While development of the Utica/Point Pleasant Shale (UPP) is extensive in Ohio (U.S.) and increasing in Pennsylvania and West Virginia, few studies report the chemistry of produced waters from UPP wells. These data have important implications for developing best management practices for handling and waste disposal, or identifying the fluid in the event of accidental spill events. Here, we evaluated the elemental and isotope chemistry of UPP produced waters from 26 wells throughout Ohio, Pennsylvania, and West Virginia to determine any unique fluid chemistries that could be used for forensic studies. Compared to the Marcellus, UPP produced waters contain higher activities of total radium (226Ra + 228Ra) and higher 228Ra/226Ra ratios. As with the Marcellus Shale, elemental ratios (Sr/Ca) and isotope ratios (87Sr/86Sr) can distinguish UPP produced waters from many conventional oil and gas formations. Sr/Ca and 87Sr/86Sr ratios can fingerprint small fractions (∼0.1%) of UPP produced water in freshwater. However, because Marcellus and UPP produced waters display similar major elemental chemistry (i.e., Na, Ca, and Cl) and overlapping ratios of Sr/Ca and 87Sr/86Sr, 228Ra/226Ra ratios may be the best tracer to distinguish these waters.

Abstract:
Unconventional methods of oil and natural gas extraction have been a growing part of North America's energy sector for the past 20-30 years. Technologies such as horizontal hydraulic fracturing have facilitated the exploitation of geologic reserves that were previously resistant to standard drilling approaches. However, the environmental risks associated with hydraulic fracturing are relatively understudied. One such hazard is the wastewater by-product of hydraulic fracturing processes: flowback and produced water (FPW). During FPW production, transport, and storage, there are many potential pathways for environmental exposure. In the current review, toxicological hazards associated with FPW surface water contamination events and potential effects on freshwater biota are assessed. This review contains an extensive survey of chemicals commonly associated with FPW samples from shale formations across North America and median 50% lethal concentration values (LC50) of corresponding chemicals for many freshwater organisms. We identify the characteristics of FPW which may have the greatest potential to be drivers of toxicity to freshwater organisms. Notably, components associated with salinity, the organic fraction, and metal species are reviewed. Additionally, we examine the current state of FPW production in North America and identify the most significant obstacles impeding proper risk assessment development when environmental contamination events of this wastewater occur. Findings within this study will serve to catalyze further work on areas currently lacking in FPW research, including expanded whole effluent testing, repeated and chronic FPW exposure studies, and toxicity identification evaluations.

Abstract:
The present research examines the combined role of the message and source of a news article in persuading political partisans about an environmental policy. In a series of three experiments, we presented participants (total N = 3457) with a realistic news article summarizing scientific evidence concerning the environmental and economic costs and benefits of hydraulic fracturing (fracking). The article’s message was manipulated to support either a conservative (pro-fracking) or liberal (anti-fracking) policy and was attributed to either a conservative news source (Fox News) or a liberal one (MSNBC). Participants who read pro-fracking articles were generally more supportive of fracking than those who read anti-fracking articles, regardless of whether articles were from an ideologically friendly or unfriendly source. Consistent with previous research, however, participants perceived articles with ideologically unfriendly messages to have worse methods than articles with ideologically friendly messages. Finally, liberal participants showed some reduction in resistance to ideologically unfriendly messages coming from an ideologically friendly source, but conservative participants did not. Implications for politicization of environmental policy and future research are discussed.

Abstract:
Oil/gas well integrity failures are a common but poorly constrained source of methane emissions to the atmosphere. As of 2014, Pennsylvania requires gas and oil well operators to report gas losses, both fugitive and process, from all active and unplugged abandoned gas and oil wells. We analyze 589,175 operator reports and find that lower-bound reported annual methane emissions averaged 22.1 Gg (-16.9, +19.5) between 2014 and 2018 from 62,483 wells, an average of only 47% of the statewide well inventory for those years. Extrapolating to the 2019 oil and gas well inventory yields well average emissions of 55.6 Gg CH4. These emissions are not currently included in the state’s oil and gas emissions inventory. We also assess compliance in reporting among operators and note anomalies in reporting and apparent workarounds to reduce reported emissions. Suggestions for improving the accuracy and reliability in reporting and reducing emissions are offered.

Abstract:

Abstract:
Mixing of acid mine drainage (AMD) and hydraulic fracturing flowback fluids (HFFF) could represent an efficient management practice to simultaneously manage two complex energy wastewater streams while reducing freshwater resource consumption. AMD discharges offer generally high sulfate concentrations, especially from the bituminous coal region of Pennsylvania; unconventional Marcellus shale gas wells generally yield HFFF enriched in alkaline earth metals such as Sr and Ba, known to cause scaling issues in oil and gas (O&G) production. Mixing the two waters can precipitate HFFF-Ba and -Sr with AMD-SO4, therefore removing them from solution. Four AMD discharges and HFFF from two unconventional Marcellus shale gas wells were characterized and mixed in batch reactors for 14 days. Ba could be completely removed from solution within 1 day of mixing in the form BaxSr1–xSO4 and no further significant precipitation occurred after 2 days. Total removal efficiencies of Ba + Sr + SO4 and the proportion of Ba and Sr in BaxSr1–xSO4 depended upon the Ba/Sr ratio in the initial HFFF. A geochemical model was calibrated from batch reactor data and used to identify optimum AMD–HFFF mixing ratios that maximize total removal efficiencies (Ba + Sr + SO4) for reuse in O&G development. Increasing Ba/Sr ratios can enhance total removal efficiency but decrease the efficiency of Ra removal. Thus, treatment objectives and intended beneficial reuse need to be identified prior to optimizing the treatment of HFFF with AMD.

Abstract:
Hydraulic fracturing of horizontal wells is a cost effective means for extracting oil and gas from low permeability formations. Hydraulic fracturing often produces considerable volumes of flowback and produced water (FPW). FPW associated with hydraulic fracturing has been shown to be a complex, often brackish mixture containing a variety of anthropogenic and geogenic compounds. In the present study, the risk of FPW releases to aquatic systems was studied using the model benthic invertebrate, Lumbriculus variegatus and field-collected FPW from a fractured well in Alberta. Acute, chronic, and pulse toxicity were evaluated to better understand the implications of accidental FPW releases to aquatic environments. Although L. variegatus is thought to have a high tolerance to many stressors, acute toxicity was significant at low concentrations (i.e. high dilutions) of FPW (48 h LC50: 4–5%). Chronic toxicity (28 d)of FPW in this species was even more pronounced with LC50s (survival/reproduction) and EC50s (total mass) at dilutions as low as 0.22% FPW. Investigations evaluating pulse toxicity (6 h and 48 h exposure) showed a significant amount of latent mortality occurring when compared to the acute results. Additionally, causality in acute and chronic bioassays differed as acute toxicity appeared to be primarily driven by salinity, which was not the case for chronic toxicity, as other stressors appear to be important as well. The findings of this study show the importance of evaluating multiple exposure regimes, the complexity of FPW, and also shows the potential aquatic risk posed by FPW releases.

Abstract:
This study examined the influence of political ideology and perceptions of benefits and risks upon State Forest recreationists’ support and opposition towards shale natural gas energy development (SGD) on public and private lands in Pennsylvania. Much of the ongoing and proposed Pennsylvania SGD infrastructure is either within or adjacent to public lands, waters, and protected areas, raising concerns about the potential environmental and social impacts upon recreation stakeholders. On-site face-to-face survey interviews were used to gather data from Pennsylvania State Forest recreationists from June to September of 2018 (n = 392). The predominantly local, educated, experienced, and politically moderate sample in this study demonstrated relatively low levels of support towards SGD on Pennsylvania public lands and relatively neutral stances towards support for SGD on private lands in Pennsylvania. Structural equation modeling results suggested that political ideology and perceptions of risks were significant predictors of support for SGD on both public and private lands in Pennsylvania. The relationship between political ideology and support for SGD on public and private lands was also partially mediated through the perceived risk of SGD in the model. Study findings contributed to previous research suggesting political attitudes may influence and supersede other factors when predicting support for SGD. A series of one-way analyses of variance further explored differences by political ideology in this study. In each of these analyses, a similar statistical trend prevailed. Those identifying themselves as conservative were significantly more likely than their moderate and liberal counterparts to support SGD on both public and private lands in Pennsylvania and perceive fewer risks from SGD on Pennsylvania State Forests. This research lent itself to the theory of landscape fit and construal level theory as State Forest recreationists may have perceived the ‘fit’ of SGD negatively and could have construed SGD abstractly, lending themselves to political ideology. From a policy and management standpoint, study findings highlight the importance of assessing and communicating State Forest recreationists’ perceptions and subsequent opinions when planning, developing, and managing SGD and related decisions in the United States.

Abstract:
Using new satellite observations and atmospheric inverse modeling, we report methane emissions from the Permian Basin, which is among the world’s most prolific oil-producing regions and accounts for >30% of total U.S. oil production. Based on satellite measurements from May 2018 to March 2019, Permian methane emissions from oil and natural gas production are estimated to be 2.7 ± 0.5 Tg a−1, representing the largest methane flux ever reported from a U.S. oil/gas-producing region and are more than two times higher than bottom-up inventory-based estimates. This magnitude of emissions is 3.7% of the gross gas extracted in the Permian, i.e., ~60% higher than the national average leakage rate. The high methane leakage rate is likely contributed by extensive venting and flaring, resulting from insufficient infrastructure to process and transport natural gas. This work demonstrates a high-resolution satellite data–based atmospheric inversion framework, providing a robust top-down analytical tool for quantifying and evaluating subregional methane emissions. Satellite observes large methane emissions from the Permian Basin in the United States. Satellite observes large methane emissions from the Permian Basin in the United States.

Abstract:
Source-pathway-receptor analyses involving solute migration pathways through soil and shallow groundwater are typically undertaken to assess how people and the environment could come into contact with chemicals associated with coal seam gas operations. For the potential short‑term and long‑term release of coal seam gas fluids from storage ponds, solute concentration and dilution factors have been calculated using a water flow and solute transport modelling framework for an unsaturated zone-shallow groundwater system. Uncertainty about dilution factors was quantified for a range of system parameters: (i) leakage rates from storage ponds combined with recharge rates, (ii) a broad combination of soil and groundwater properties, and (iii) a series of increasing travel distances through soil and groundwater. Calculated dilution factors in the soil increased from sand to loam soil and increased with an increasing recharge rate, while dilution decreased for a decreasing leak rate and leak duration. In groundwater, dilution factors increase with increasing aquifer hydraulic conductivity and riverbed conductance. For a hypothetical leak duration of three years, the combined soil and groundwater dilution factors are larger than 6980 for more than 99.97% of bores that are likely to be farther than 100 m from the source. Dilution factors were more sensitive to uncertainty in leak rates than recharge rates. Based on this dilution factor, a comparison of groundwater predicted environmental concentrations and predicted no-effect concentrations for a subset of hydraulic fracturing chemicals used in Australia revealed that for all but two of the evaluated chemicals the estimated groundwater concentration (for a hypothetical water bore at 100 m from the solute source) is smaller than the no-effect concentration for the protection of aquatic ecosystems.

Abstract:
Hydraulic fracturing (hydrofracking) for natural gas has increased rapidly in the area of the Marcellus Shale in the last thirty years but estimates of CH4 emissions from hydrofracking operations are still uncertain. Previous studies on CH4 emissions at hydrofracking operations have used bottom-up approaches collected at discrete timepoints or discrete aerial surveys covering a wide spatial area, constraining the temporal scale of inference regarding these emissions. This project monitored atmospheric CH4 concentrations and stable carbon isotopes at a half-hourly temporal resolution from a 20-m tower downwind of a hydrofracking well pad in West Virginia for eighteen months. We collected four months of baseline observations prior to onsite well development to construct an empirical artificial neural-network model of baseline CH4 concentrations. We compared the CH4 concentrations against the ANN-modeled CH4 baseline to identify CH4 concentration spikes that coincided with different stages of onsite well development, from the baseline period through fracking. CH4 concentration spikes were significantly more frequent than baseline conditions during the vertical drilling and fracking phases of operations. We found that the median magnitude of CH4 concentration spikes during the vertical drilling phase was 316% larger than that of the baseline phase, and the median magnitude of CH4 concentration spikes was 509% larger in the hydraulic stimulation (fracking) stage compared to the baseline phase. We also partitioned the sources of measured CH4 concentrations to biogenic ruminant and geologic shale gas isotopic signatures by measuring 13CH4 gas at high temporal resolution and using a source-partitioning 13CH4 model. The measured median value of half-hourly CH4 concentration spikes attributed to a geologic shale gas isotopic origin was 27% larger than the median CH4 concentration spikes attributed to ruminants, and the maximum half-hourly CH4 concentration spike attributed to shale gas was up to 179% higher than maximum CH4 concentration spike for ruminant-dominated half-hours. This study developed a framework for off-site, single tower measurements to identify CH4 concentration spikes associated with the phases of unconventional natural gas well development in a complex CH4 emissions airshed.

Abstract:
This study is set to quantify the impact of oil and gas production on the commuting pattern in the Permian Basin region. In particular, we focus on cross-county commuting that has shown a significant increase during the recent Permian Basin shale boom. Anecdotal evidence suggests that the increase is mainly driven by extended daily commuting and long-distance commuting (LDC) tied to the oil and gas industry. Our regression analysis integrating county-level commuting data and shale energy production data confirms that the impact is statistically significant. Using data from 67 counties in New Mexico and Texas between 2002 and 2017, we find that on average a one-million-BBLs increase in annual oil production leads to an increase of 100 inward commuters and an increase of 15 outward commuters. The net impact (inward – outward) is an increase of 85 commuters. By linking the empirical findings to the potential health, environmental, and socio-economic impacts of shale development with commuting being the channel of influence, further exploration suggests that the health and environmental impacts of extended daily commuting are much more significant compared to LDC. As far as the socio-economic aspect is concerned, both extended daily commuting and LDC can have significant impacts.

Abstract:
Shale gas extraction processes generate a large amount of hypersaline wastewater, whose spills or discharges may significantly increase the bromide levels in downstream water supplies and result in the formation of brominated disinfection byproducts (DBPs) upon chlorination. Although a few studies have investigated selective bromide removal from produced water, the low removal efficiencies and complex system setups are not desirable. In this study, we examined a simple cost-effective approach for selective bromide removal from produced water relying on the oxidation by un-activated peroxymonosulfate (PMS). More than 95% of bromide was removed as Br2(g) in less than 10 min under weakly acidic conditions without significant formation of Cl2(g) even when the chloride concentration was more than two orders of magnitude higher. A kinetic model considering the involved reactions was then developed to describe the process well under various reaction conditions. The organic compounds in produced water neither noticeably lowered bromide removal efficiency nor reacted with the halogen species to form halogenated byproducts. The tests in batch and continuously-stirred tank reactor systems suggested that it was feasible to achieve both high bromide removal and neutral effluent pH such that further pH adjustment was not necessary before discharge. After the treatment, the effect of the produced water on DBP formation was largely eliminated.

Abstract:
Produced water is a byproduct of oil and gas production. The chemistry of produced water may provide information about the source of the fluid and its evolution, leading to an improved understanding of the hydrology of petroleum systems. In this study, samples from 19 wells from the Tuscaloosa Marine Shale (TMS) in Mississippi and Louisiana, USA were analyzed for their major and trace element compositions. Data obtained from produced waters from the TMS were compared to existing chemical data from produced waters collected from nearby hydrocarbon reservoir rocks within the Gulf Coast Basin. The results show that produced waters from the TMS are highly saline, with a mean concentration of 15.9 g/L of total dissolved solids. Comparison of the chemistry of produced water from the TMS to early flowback waters demonstrated a rapid shift from the more dilute fracturing fluid to the formation water endmember composition. Most of the trace metals showed a moderate to strong correlation with the overall salinity of the waters. Concentrations of Cu and V showed a moderate correlation with the amount of oil produced from the TMS wells, suggesting that these elements are strongly affiliated with the kerogen and subsequent dissolved (<0.45 μm) organic phases. Analysis of the volume of produced water compared to the volume of water used during hydraulic fracturing indicates that 15%–110% of the water volume used for fracking had been returned to the surface over the 2–5 year production period of the sampled wells. Chloride to bromide ratios suggest that the formation water in the TMS was derived from evaporated seawater. Comparison to historical data for produced waters in other formations in and around the Mississippi Salt Basin showed that waters in all the formations had a consistent origin (bitterns likely derived from the formation of the Louann salt). This implies that over geologic time periods fluids migrated through the TMS despite its low permeability present-day. The TMS also exhibited lower concentrations of dissolved transition metals such as Zn and Pb relative to those described in adjacent formations. This observation may suggest the presence of larger amounts of H2S, limiting the solubility of sulfide phases, in the shale unit relative to adjacent reservoir units.

Abstract:
Hydraulic fracturing (HF) in the Duvernay Formation near Fox Creek, Alberta, Canada, has produced some of the most prolific clusters of induced seismicity. In this paper, we describe newly emerging clusters of events occurring in previously quiescent (and undeveloped) areas of the Duvernay Formation. In the Duvernay East Shale Basin, an industry supplemented waveform database is examined using a variety of seismological techniques. Here, strike-slip events as large as 4.18 ML have been felt in nearby cities. Temporal relationships suggest these clusters are almost certainly (>99.7% confidence) caused by nearby HF. Spatially, these earthquakes tend to occur in the strata directly overlying the Duvernay Formation and laterally near a horizontal well. One exceptional cluster clearly delineates a 1.5 km offset between its centroid and the inducing horizontal well, raising questions about the earthquake triggering mechanism. Westward in the Duvernay, two minor clusters within the Willesden Green region appear to be tenuously related to HF completions. This study also places constraints on the structural geology of faulting occurring in the Rocky Mountain House Seismogenic Zone – a region of induced seismicity related to secondary recovery in the Strachan D-3A pool. Here, our moment tensors and double difference relocations describe thrust-slip on a fault underlying the target formation. Last, the largest event (4.27 ML) in our study area was likely natural, due to its deeper hypocentral depth (~15 km) and non-correspondence with industrial operations. Overall, the newly emerging clusters are consistent with reactivation of basement rooted faults.

Abstract:
The data in this report are associated with https://doi.org/10.1016/j.scitotenv.2020.137085 and include data on water volumes and water quality related to the major unconventional oil and gas plays in the U.S.. The data include volumes of water co-produced with oil and gas production, county-level estimates of annual water use volumes by various sectors, including hydraulic fracturing water use, and the quality of produced water. The data on volumes of produced water and hydraulic fracturing water volumes were obtained from the IHS Enerdeq and FracFocus databases. Water use in other sectors were obtained from the U.S. Geological Survey water use database. Data on produced water quality were obtained from the USGS produced waters database.

Abstract:
Waters co-produced with hydrocarbons from unconventional oil and gas reservoirs such as the hydraulically fractured Marcellus Shale in the Appalachian Basin, USA, contain high levels of total dissolved solids (TDS), including Ba, which has been variously ascribed to drilling mud dissolution, interaction with pore fluids or shale exchangeable sites, or fluid migration through fractures. Here we show that Middle Devonian Marcellus Shale produced waters contain some of the heaviest Ba (high 138Ba/134Ba) measured to date (δ138Ba = +0.4‰ to +1.5‰ ±0.06‰), and are distinct from overlying Upper Devonian/Lower Mississippian reservoirs (δ138Ba = -0.8‰ to -0.5‰). Marcellus Shale produced water values do not overlap with drilling mud barite (δ138Ba ≈ 0.0‰), and are significantly offset from Ba reservoirs within the producing portion of the Marcellus Shale, including exchangeable sites and carbonate cement. Precipitation, desorption and diffusion processes are insufficient or in the wrong direction to produce the observed enrichments in heavy Ba. We hypothesize that the produced water is derived primarily from brines adjacent to and most likely below the Marcellus Shale, although such deep brines have not yet been obtained for Ba isotope analysis. Barium isotopes show promise for tracking formation waters and for understanding water-rock interaction under downhole conditions.

Abstract:
Unconventional oil and natural gas extraction (UOG) combines directional drilling and hydraulic fracturing and produces billions of liters of wastewater per year. Herein, we review experimental studies that evaluated the potential endocrine-mediated health impacts of exposure to a mixture of 23 UOG chemicals commonly found in wastewater. The purpose of this manuscript is to synthesize and summarize a body of work using the same UOG-mix but with different model systems and physiological endpoints in multiple experiments. The studies reviewed were conducted in laboratory animals (mice or tadpoles) and human tissue culture cells. A key feature of the in vivo studies was the use of four environmentally relevant doses spanning three orders of magnitude ranging from concentrations found in surface and ground water in UOG dense areas to concentrations found in UOG wastewater. This UOG-mix exhibited potent antagonist activity for the estrogen, androgen, glucocorticoid, progesterone, and thyroid receptors in human tissue culture cells. Subsequently, pregnant mice were administered the UOG-mix in drinking water and offspring were examined in adulthood or to tadpoles. Developmental exposure profoundly impacted pituitary hormone concentrations, reduced sperm counts, altered folliculogenesis, and increased mammary gland ductal density and preneoplastic lesions in mice. It also altered energy expenditure, exploratory and risk-taking behavior, the immune system in three immune models in mice, and affected basal and antiviral immunity in frogs. These findings highlight the diverse systems affected by developmental EDC exposure and the need to examine human and animal health in UOG regions.

Abstract:
Membrane-based desalination system under consideration for shale gas fracturing flowback wastewater treatment involves ultrafiltration (UF), reverse osmosis (RO) and storage tanks. The membrane unit (UF, RO) consists of online washing, operation and offline chemical washing sub-units. These sub-units operate in semi-continuous mode and have the similar characteristics as batch water-using processes. Based on their semi-continuous behaviors, the models of UF and RO sub-units are developed. The objective is to maximize the total water production ratio and profit while minimize storage tank capacity. Three nonlinear programming optimization models are developed for optimal design of UF-RO treatment system for shale gas fracturing flowback wastewater. Two scenarios – fixed schedule and fixed operating period for UF/RO treatment sub-units are investigated. Results show that with the increasing the operation duration of treatment sub-units, the water production ratio and profit will increase. The schedule of treatment sub-units has significant impact on the water-storage profiles, without adversely affecting the water production ratio. The proposed approach can guide the design of UF-RO desalination system.

Abstract:

Abstract:
The organic composition of produced waters (flowback and formation waters) from the middle member of the Bakken Formation and the Three Forks Formation in the Williston Basin, North Dakota were examined to aid in the remediation of surface contamination and help develop treatment methods for produced-water recycling. Twelve produced water samples were collected from the Bakken and Three Forks Formations and analyzed for non-purgeable dissolved organic carbon (NPDOC), acetate, and extractable hydrocarbons. NPDOC and acetate concentrations from sampled wells from ranged from 33-190 mg per liter (mg/L) and 16–40 mg/L, respectively. Concentrations of individual extractable hydrocarbon compounds ranged from less than 1 to greater than 400 μg per liter (μg/L), and included polycyclic aromatic hydrocarbons (PAHs), phenolic compounds, glycol ethers, and cyclic ketones. While the limited number of samples, varying well production age, and lack of knowledge of on-going well treatments complicate conclusions, this report adds to the limited knowledge of organics in produced waters from the Bakken and Three Forks Formations.

Abstract:
Background Hydraulic fracturing together with directional and horizontal well drilling (unconventional oil and gas (UOG) development) has increased substantially over the last decade. UOG development is a complex process presenting many potential environmental health hazards, raising serious public concern. Aim To conduct a scoping review to assess what is known about the human health outcomes associated with exposure to UOG development. Methods We performed a literature search in MEDLINE and SCOPUS for epidemiological studies of exposure to UOG development and verified human health outcomes published through August 15, 2019. For each eligible study we extracted data on the study design, study population, health outcomes, exposure assessment approach, statistical methodology, and potential confounders. We reviewed the articles based on categories of health outcomes. Results We identified 806 published articles, most of which were published during the last three years. After screening, 40 peer-reviewed articles were selected for full text evaluation and of these, 29 articles met our inclusion criteria. Studies evaluated pregnancy outcomes, cancer incidence, hospitalizations, asthma exacerbations, sexually transmitted diseases, and injuries or mortality from traffic accidents. Our review found that 25 of the 29 studies reported at least one statistically significant association between the UOG exposure metric and an adverse health outcome. The most commonly studied endpoint was adverse birth outcomes, particularly preterm deliveries and low birth weight. Few studies evaluated the mediating pathways that may underpin these associations, highlighting a clear need for research on the potential exposure pathways and mechanisms underlying observed relationships. Conclusions This review highlights the heterogeneity among studies with respect to study design, outcome of interest, and exposure assessment methodology. Though replication in other populations is important, current research points to a growing body of evidence of health problems in communities living near UOG sites.

Abstract:
Shale gas development can negatively impact those residing in close proximity to projects. Evidence from protests in Europe and the United States suggests a growing prevalence of “NUMBYism” (Not Under My Backyard) sentiment. There is little public discourse about the public acceptance, particularly among those directly affected, of shale gas development in China. Moreover, little research has been done examining whether locally affected publics support or oppose shale gas development, putting policymakers at a disadvantage in terms of risk communication and effective energy governance. Through in-depth interviews with local residents (n = 25) in Weiyuan county that has the largest shale gas reserves in China, the present study extends prior literature on the “NUMBY” phenomenon by exploring local residents’ attitudes toward shale gas development, both locally and distantly. Here we find approximately 20% of our interviewees express views that are consistent with NUMBYism – oppose local development but support or are indifferent to development elsewhere. The rest express views that are fully supportive (52%) or opposed (8%) regardless of local or distant development, or indifferent to local development but either supportive or indifferent to development elsewhere (20%). We find interrelated factors such as national identity – not observed in previous studies – playing an important role in how residents view development. Moreover, drawing upon construal level theory, we also examine the role that different dimensions of psychological distance (e.g., social, temporal, uncertainty, and experiential) may play in explaining these views. These findings may inform policy design and risk communication about shale gas development in China.

Abstract:
Unconventional shale gas exploitation presents complex problems in terms of radioactive waste disposal. Large volumes of saline produced water resulting from hydraulic fracturing are typically enriched in radium isotopes, up to several hundred Bq/dm3, orders of magnitude above national discharge limits. There is a need, therefore, to decontaminate the fluid prior to discharge, preferably by creating a less problematic radium-containing, solid waste form. Barite (barium sulphate) co-precipitation is a cost-effective method for achieving these objectives, provided the process can be controlled. In this work, radium recovery of ~90% has been achieved for simulant produced waters containing 100 Bq/dm3, using a single, optimised co-precipitation step. However, salinity has a significant effect on the efficiency of the process; higher salinity solutions requiring substantially more reagent to achieve the same recovery. If >90% radium removal is sought, multiple co-precipitation steps provide a much faster alternative than post-precipitation recrystallization of the barite solid phase, albeit at higher cost. The resulting solid waste has a relatively high specific radium activity but a much smaller volume, which presents a less intractable disposal problem for site operators than large volumes of radium-contaminated fluid.

Abstract:
Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited disposal capacity, and more stringent regulations. Meanwhile, large volumes of freshwater are used for hydraulic fracturing. The goal of this study is to develop cost-effective technologies, and optimize system design and operation to treat highly saline produced water (120–140 g/L total dissolved solids) for hydraulic fracturing. Produced water was collected from a salt water disposal facility in the Permian Basin, New Mexico. Chemical coagulation (CC) using ferric chloride and aluminum sulfate as coagulants was compared with electrocoagulation (EC) with aluminum electrodes for removal of suspended contaminants. The effects of coagulant dose, current density, and hydraulic retention time during EC on turbidity removal were investigated. Experimental results showed that aluminum sulfate was more efficient and cost-effective than ferric chloride for removing turbidity from produced water. The optimal aluminum dose was achieved at operating current density of 6.60 mA/cm2 and 12 min contact time during EC treatment, which resulted in 74% removal of suspended solids and 53%–78% removal of total organic carbon (TOC). The energy requirement of EC was calculated 0.36 kWh/m3 of water treated. The total operating cost of EC was estimated $0.44/m3 of treated water, which is 1.7 or 1.2 times higher than CC using alum or ferric chloride as the coagulant, respectively. The EC operating cost was primarily associated with the consumption of aluminum electrode materials due to faradaic reactions and electrodes corrosions. EC has the advantage of shorter retention time, in situ production of coagulants, less sludge generation, and high mobility for onsite produced water treatment. The fine particles and other contaminants after coagulation were further treated in continuous-flow columns packed with different filter media, including agricultural waste products (pecan shell, walnut shell, and biochar), and new and spent granular activated carbon (GAC). Turbidity, TOC, metals, and electrical conductivity were monitored to evaluate the performance of the treatment system and the adsorption capacities of different media. Biochar and GAC showed the greatest removal of turbidity and TOC in produced water. These treatment technologies were demonstrated to be effective for the removal of suspended constituents and iron, and to produce a clean brine for onsite reuse, such as hydraulic fracturing.

Abstract:
The purpose of this study is to evaluate the impact of hydraulic fracturing on groundwater quality in Ector, Midland, and Martin Counties located in the Permian Basin, West Texas. Chemical fluids used in hydraulic fracturing and groundwater quality parameters (chloride, fluoride, calcium carbonate, nitrate, pH, and total dissolved solids), were statistically analyzed assuming a normal probability function distribution and through a one-way analysis of variance of the parameters. Additionally, the depth of groundwater well versus water quality analysis as well as historical analysis of groundwater quality parameters of wells were performed. The result for each county was individually examined and contrasted with the other two counties, in order to make inferences about groundwater quality and oil and gas activities for the three counties. Potential risks to human health from the abnormal levels of the groundwater quality parameters studied were also discussed based on the Environmental Protection Agency’s (EPA) standards. This research provides important information on groundwater quality in the Permian Basin and contributes on understanding the response to development in hydraulic fracturing.

Abstract:
More than 1 million wells may have been completed using hydraulic fracturing techniques in the USA alone; however, there have been few case studies exploring the impacts on water resources due to methane migration. This study evaluated the results of three investigations initiated by the US Environmental Protection Agency, that were subsequently described in published studies at Dimock in Pennsylvania, Parker-Hood County in Texas, and Pavillion in Wyoming, as well as another study completed at Sugar Run in northeast Pennsylvania. In addition, earlier investigations at Shaws Corner in Pennsylvania, Jackson County in West Virginia, Garfield County in Colorado, and Bainbridge in Ohio are summarized. The most common cause of incidents was the presence of uncemented sections of production casings in wells that allowed gas migration from intermediate depths to shallow freshwater aquifers. In three cases, an inadequate depth of the primary top of cement (TOC) also contributed to impacts. Sources of methane were best identified through analyses of isotopes on samples from production casings, annular spaces, and water wells. In Dimock, some isotope signatures changed with time, after the completion of remedial actions. In Parker-Hood County, where impacts were not related to gas well activity, noble gas analyses were also needed to determine the source of gas. At Pavillion, where maximum methane concentrations in water wells were <1 mg/L, no significant impacts were documented. For all the sites, most or all of the fugitive gas incidents may have been prevented by fully cementing production casings to the land surface.

Abstract:
Rapid growth in U.S. unconventional oil and gas made energy more available and affordable globally, but brought environmental concerns, especially related to water. We analyzed water-related sustainability of energy extraction focusing on: (a) meeting rapidly rising water demand for hydraulic fracturing (HF), and (b) managing rapidly growing volumes of water co-produced with oil and gas (produced water, PW). We analyzed historical (2009–2017) HF water and PW volumes in ~73,000 wells and projected future water volumes in major U.S. unconventional oil (semiarid regions) and gas (humid regions) plays. Results show a marked increase in HF water use, depleting groundwater in some semiarid regions (e.g. by ≤58 ft [18 m]/yr in Eagle Ford). PW from oil reservoirs (e.g. Permian) is ~15× higher than that from gas reservoirs (Marcellus). Water issues related to both HF water demand and PW supplies may be partially mitigated by closing the loop through reusing PW for HF of new wells. However, projected PW volumes exceed HF water demand in semiarid Bakken (2.1×) and Permian Midland (1.3×) and Delaware (3.7×) oil plays, with the Delaware accounting for ~50% of projected U.S. oil production. Therefore, water issues could constrain future energy production, particularly in semiarid oil plays.

Abstract:
This work addresses three significant issues associated with hydraulic fracturing in US shale fields: flaring/venting of excess natural gas, disposal of flowback water and freshwater procurement. Flaring/venting of excess gas is a significant contributor to global emissions. This work presents a novel utilization concept, wherein excess gas is used onsite to power reverse osmosis (RO)-based treatment of flowback water to supply freshwater for oilfield operations. This study details technical and techno-economic analyses of the above concept. An analytical model is extended and improved to quantify RO-based freshwater production for flowback water of different salinities. The technical performance of RO systems is analyzed and compared with two competing gas utilization technologies (thermal desalination, atmospheric water harvesting). The use of these technologies in the top eight US shale fields is analyzed, and a techno-economic analysis of RO-based water treatment is conducted. Results indicate that this concept will significantly benefit the Eagle Ford and Niobrara shales. It can meet 200% of water requirements and reduce wastewater disposal by 60% in the Eagle Ford. Furthermore, such RO-based projects can have favorable payback periods of as low as one year. Importantly, this waste-to-value concept has worldwide relevance since the underlying issues are present globally.

Abstract:

Abstract:
Recent technological progresses have unlocked tremendous shale energy resources, leading to increased production of oil and gas and a variety of new environmental pollution issues in the United States. One such example is management of produced waters, which are often disposed of via deep well injection. Produced water injection has been linked to induced seismicity. Thus, there are strong incentives for alternative management strategies that come with new, uncertain environmental risks. This paper summarizes studies of sediment pollution due to oil and gas production. The goal is to highlight potential environmental risks associated with produced water management, including long-term contamination of sediments.

Abstract:
Article: Air quality impacts from oil and natural gas development in Colorado