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Hydraulic fracturing

Elise G Elliott, Pauline Trinh, Xiaomei Ma, Brian P Leaderer, Mary H Ward, Nicole C Deziel
The widespread distribution of unconventional oil and gas (UO&G) wells and other facilities in the United States potentially exposes millions of people to air and water pollutants, including known or suspected carcinogens. Childhood leukemia is a particular concern because of the disease severity, vulnerable population, and short disease latency. A comprehensive review of carcinogens and leukemogens associated with UO&G development is not available and could inform future exposure monitoring studies and human health assessments...
October 23, 2016: Science of the Total Environment
William T Stringfellow, Mary Kay Camarillo, Jeremy K Domen, Whitney L Sandelin, Charuleka Varadharajan, Preston D Jordan, Matthew T Reagan, Heather Cooley, Matthew G Heberger, Jens T Birkholzer
Chemical additives used for hydraulic fracturing and matrix acidizing of oil reservoirs were reviewed and priority chemicals of concern needing further environmental risk assessment, treatment demonstration, or evaluation of occupational hazards were identified. We evaluated chemical additives used for well stimulation in California, the third largest oil producing state in the USA, by the mass and frequency of use, as well as toxicity. The most frequently used chemical additives in oil development were gelling agents, cross-linkers, breakers, clay control agents, iron and scale control agents, corrosion inhibitors, biocides, and various impurities and product stabilizers used as part of commercial mixtures...
October 12, 2016: Environmental Pollution
Christopher James Grant, Allison K Lutz, Aaron D Kulig, Mitchell R Stanton
Unconventional natural gas development and hydraulic fracturing practices (fracking) are increasing worldwide due to global energy demands. Research has only recently begun to assess fracking impacts to surrounding environments, and very little research is aimed at determining effects on aquatic biodiversity and contaminant biomagnification. Twenty-seven remotely-located streams in Pennsylvania's Marcellus Shale basin were sampled during June and July of 2012 and 2013. At each stream, stream physiochemical properties, trophic biodiversity, and structure and mercury levels were assessed...
October 14, 2016: Ecotoxicology
Derek Johnson, Robert Heltzel, Andrew Nix, Rebekah Barrow
Implications Development of representative, engine dynamometer test-cycles, from in-use activity data, is crucial in understanding fuel efficiency and emissions for engine operating modes that are different from cycles mandated by the Code of Federal Regulations. Representative cycles were created for the prime movers of unconventional well development - OTR trucks, drilling and hydraulic fracturing engines. The representative cycles are implemented on scaled engines to reduce fuel consumption during research and development of new technologies in controlled laboratory environments...
October 10, 2016: Journal of the Air & Waste Management Association
Yuqing Sun, Season S Chen, Daniel C W Tsang, Nigel J D Graham, Yong Sik Ok, Yujie Feng, Xiang-Dong Li
Zero-valent iron (ZVI) was tested for the removal of 150 μg L(-1) As(V) and 350 μg L(-1) Se(VI) in high-salinity (ionic strength 0.35-4.10 M) flowback water of hydraulic fracturing. Over 90% As(V) and Se(VI) was removed by 2.5 g L(-1) ZVI in Day-14 flowback water up to 96-h reaction, with the remaining concentration below the maximum contaminant level for As(V) and criterion continuous concentration for Se(VI) recommended by US EPA. The kinetics of As(V) and Se(VI) removal followed a pseudo-second-order rate expression with the observed rates of 4...
October 5, 2016: Chemosphere
Daniele Vanni, Renato Galzio, Anna Kazakova, Andrea Pantalone, Giovanni Grillea, Marcello Bartolo, Vincenzo Salini, Vincenzo Magliani
Currently, there is no general consensus about the management of osteoporotic vertebral fractures (OVF). In the past, conservative treatment for at least one month was deemed appropriate for the majority of vertebral fractures. When pain persisted after conservative treatment, it was necessary to consider surgical interventions including: vertebroplasty for vertebral fractures with less than 30% loss of height of the affected vertebral body and kyphoplasty for vertebral fractures with greater than 30% loss of height...
March 2016: J Spine Surg
Tao Wen, M Clara Castro, Jean-Philippe Nicot, Chris M Hall, Toti Larson, Patrick Mickler, Roxana Darvari
This study places constraints on the source and transport mechanisms of methane found in groundwater within the Barnett Shale footprint in Texas using dissolved noble gases, with particular emphasis on (84)Kr and (132)Xe. Dissolved methane concentrations are positively correlated with crustal (4)He, (21)Ne, and (40)Ar and suggest that noble gases and methane originate from common sedimentary strata, likely the Strawn Group. In contrast to most samples, four water wells with the highest dissolved methane concentrations unequivocally show strong depletion of all atmospheric noble gases ((20)Ne, (36)Ar, (84)Kr, (132)Xe) with respect to air-saturated water (ASW)...
October 14, 2016: Environmental Science & Technology
Joshua W Brownlow, Joe C Yelderman, Scott C James
Interaction between hydraulically generated fractures and existing wells (frac hits) could represent a potential risk to groundwater. In particular, frac hits on abandoned oil and gas wells could lead to upward leakage into overlying aquifers, provided migration pathways are present along the abandoned well. However, potential risk to groundwater is relatively unknown because few studies have investigated the probability of frac hits on abandoned wells. In this study, actual numbers of frac hits were not determined...
September 27, 2016: Ground Water
Erin E Yost, John Stanek, Lyle D Burgoon
Despite growing concerns over the potential for hydraulic fracturing to impact drinking water resources, there are limited data available to identify chemicals used in hydraulic fracturing fluids that may pose public health concerns. In an effort to explore these potential hazards, a multi-criteria decision analysis (MCDA) framework was employed to analyze and rank selected subsets of these chemicals by integrating data on toxicity, frequency of use, and physicochemical properties that describe transport in water...
September 22, 2016: Science of the Total Environment
Andrew J Kondash, Elizabeth Albright, Avner Vengosh
The management and disposal of flowback and produced waters (FP water) is one of the greatest challenges associated with unconventional oil and gas development. The development and production of unconventional natural gas and oil is projected to increase in the coming years, and a better understanding of the volume and quality of FP water is crucial for the safe management of the associated wastewater. We analyzed production data using multiple statistical methods to estimate the total FP water generated per well from six of the major unconventional oil and gas formations in the United States...
September 15, 2016: Science of the Total Environment
Katherine E Manz, Gregory Haerr, Jessica Lucchesi, Kimberly E Carter
The objective of this study was to understand the adsorption ability of a surfactant and a non-surfactant chemical additive used in hydraulic fracturing onto shale and GAC. Experiments were performed at varying temperatures and sodium chloride concentrations to establish these impacts on the adsorption of the furfural (a non-surfactant) and 2-Butoxyethanol (2-BE) (a surfactant). Experiments were carried out in continuously mixed batch experiments with Langmuir and Freundlich isotherm modeling. The results of the experiments showed that adsorption of these compounds onto shale does not occur, which may allow these compounds to return to the surface in flowback and produced waters...
December 2016: Chemosphere
Pavel Zuloaga-Molero, Wei Yu, Yifei Xu, Kamy Sepehrnoori, Baozhen Li
The recent development of tight oil reservoirs has led to an increase in oil production in the past several years due to the progress in horizontal drilling and hydraulic fracturing. However, the expected oil recovery factor from these reservoirs is still very low. CO2-based enhanced oil recovery is a suitable solution to improve the recovery. One challenge of the estimation of the recovery is to properly model complex hydraulic fracture geometries which are often assumed to be planar due to the limitation of local grid refinement approach...
2016: Scientific Reports
Sara Wylie, Kim Schultz, Deborah Thomas, Chris Kassotis, Susan Nagel
This article describes Dr Theo Colborn's legacy of inspiring complementary and synergistic environmental health research and advocacy. Colborn, a founder of endocrine disruption research, also stimulated study of hydraulic fracturing (fracking). In 2014, the United States led the world in oil and gas production, with fifteen million Americans living within one mile of an oil or gas well. Colborn pioneered efforts to understand and control the impacts of this sea change in energy production. In 2005, her research organization The Endocrine Disruption Exchange (TEDX) developed a database of chemicals used in natural gas extraction and their health effects...
September 13, 2016: New Solutions: a Journal of Environmental and Occupational Health Policy: NS
Genevieve A Kahrilas, Jens Blotevogel, Edward R Corrin, Thomas Borch
Hydraulic fracturing fluid (HFF) additives are used to enhance oil and gas extraction from unconventional shale formations. Several kilometers downhole, these organic chemicals are exposed to temperatures up to 200 °C, pressures above 10 MPa, high salinities, and a pH range from 5-8. Despite this, very little is known about the fate of HFF additives under these extreme conditions. Here, stainless steel reactors are used to simulate the downhole chemistry of the commonly used HFF biocide glutaraldehyde (GA)...
October 18, 2016: Environmental Science & Technology
Viet T Chau, Zdeněk P Bažant, Yewang Su
Recent analysis of gas outflow histories at wellheads shows that the hydraulic crack spacing must be of the order of 0.1 m (rather than 1 m or 10 m). Consequently, the existing models, limited to one or several cracks, are unrealistic. The reality is 10(5)-10(6) almost vertical hydraulic cracks per fracking stage. Here, we study the growth of two intersecting near-orthogonal systems of parallel hydraulic cracks spaced at 0.1 m, preferably following pre-existing rock joints. One key idea is that, to model lateral cracks branching from a primary crack wall, crack pressurization, by viscous Poiseuille-type flow, of compressible (proppant-laden) frac water must be complemented with the pressurization of a sufficient volume of micropores and microcracks by Darcy-type water diffusion into the shale, to generate tension along existing crack walls, overcoming the strength limit of the cohesive-crack or crack-band model...
October 13, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
J D Hyman, J Jiménez-Martínez, H S Viswanathan, J W Carey, M L Porter, E Rougier, S Karra, Q Kang, L Frash, L Chen, Z Lei, D O'Malley, N Makedonska
Despite the impact that hydraulic fracturing has had on the energy sector, the physical mechanisms that control its efficiency and environmental impacts remain poorly understood in part because the length scales involved range from nanometres to kilometres. We characterize flow and transport in shale formations across and between these scales using integrated computational, theoretical and experimental efforts/methods. At the field scale, we use discrete fracture network modelling to simulate production of a hydraulically fractured well from a fracture network that is based on the site characterization of a shale gas reservoir...
October 13, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
A Peirce
Hydraulic fractures are tensile cracks that propagate in pre-stressed solid media due to the injection of a viscous fluid. Developing numerical schemes to model the propagation of these fractures is particularly challenging due to the degenerate, hypersingular nature of the coupled integro-partial differential equations. These equations typically involve a singular free boundary whose velocity can only be determined by evaluating a distinguished limit. This review paper describes a class of numerical schemes that have been developed to use the multiscale asymptotic behaviour typically encountered near the fracture boundary as multiple physical processes compete to determine the evolution of the fracture...
October 13, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Ivan C Christov, Hari S Viswanathan
This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO2) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field...
October 13, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Rebecca A Daly, Mikayla A Borton, Michael J Wilkins, David W Hoyt, Duncan J Kountz, Richard A Wolfe, Susan A Welch, Daniel N Marcus, Ryan V Trexler, Jean D MacRae, Joseph A Krzycki, David R Cole, Paula J Mouser, Kelly C Wrighton
Hydraulic fracturing is the industry standard for extracting hydrocarbons from shale formations. Attention has been paid to the economic benefits and environmental impacts of this process, yet the biogeochemical changes induced in the deep subsurface are poorly understood. Recent single-gene investigations revealed that halotolerant microbial communities were enriched after hydraulic fracturing. Here, the reconstruction of 31 unique genomes coupled to metabolite data from the Marcellus and Utica shales revealed that many of the persisting organisms play roles in methylamine cycling, ultimately supporting methanogenesis in the deep biosphere...
2016: Nature Microbiology
Mary Kay Camarillo, Jeremy K Domen, William T Stringfellow
Produced water is a significant waste stream that can be treated and reused; however, the removal of production chemicals-such as those added in hydraulic fracturing-must be addressed. One motivation for treating and reusing produced water is that current disposal methods-typically consisting of deep well injection and percolation in infiltration pits-are being limited. Furthermore, oil and gas production often occurs in arid regions where there is demand for new water sources. In this paper, hydraulic fracturing chemical additive data from California are used as a case study where physical-chemical and biodegradation data are summarized and used to screen for appropriate produced water treatment technologies...
December 1, 2016: Journal of Environmental Management
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