Spatial and Temporal Correlation of Water Quality Parameters of Produced Waters from Devonian-Age Shale following Hydraulic Fracturing
01 Mar 2013-Environmental Science & Technology (American Chemical Society)-Vol. 47, Iss: 6, pp 2562-2569
TL;DR: Water quality analysis in this study may help guide water management strategies for development of unconventional gas resources through comparisons against brines from adjacent formations.
Abstract: The exponential increase in fossil energy production from Devonian-age shale in the Northeastern United States has highlighted the management challenges for produced waters from hydraulically fractured wells. Confounding these challenges is a scant availability of critical water quality parameters for this wastewater. Chemical analyses of 160 flowback and produced water samples collected from hydraulically fractured Marcellus Shale gas wells in Pennsylvania were correlated with spatial and temporal information to reveal underlying trends. Chloride was used as a reference for the comparison as its concentration varies with time of contact with the shale. Most major cations (i.e., Ca, Mg, Sr) were well-correlated with chloride concentration while barium exhibited strong influence of geographic location (i.e., higher levels in the northeast than in southwest). Comparisons against brines from adjacent formations provide insight into the origin of salinity in produced waters from Marcellus Shale. Major cations...
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TL;DR: Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help effectively manage water-quality risks associated with unconventional gas industry today and in the future.
Abstract: Unconventional natural gas resources offer an opportunity to access a relatively clean fossil fuel that could potentially lead to energy independence for some countries. Horizontal drilling and hydraulic fracturing make the extraction of tightly bound natural gas from shale formations economically feasible. These technologies are not free from environmental risks, however, especially those related to regional water quality, such as gas migration, contaminant transport through induced and natural fractures, wastewater discharge, and accidental spills. We review the current understanding of environmental issues associated with unconventional gas extraction. Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help manage these water-quality risks today and in the future.
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TL;DR: Analysis of published data reveals evidence for stray gas contamination, surface water impacts in areas of intensive shale gas development, and the accumulation of radium isotopes in some disposal and spill sites.
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TL;DR: In this article, the authors argue that the switch from coal to natural gas for electricity generation will reduce sulfur, nitrogen, mercury, and particulate air pollution, but the question of whether natural gas will displace coal compared with renewables is open.
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Cites background from "Spatial and Temporal Correlation of..."
...These naturally occurring brines are often saline to hypersaline (35,000 to 200,000 mg/L TDS) (37) and contain potentially toxic levels of elements such as barium, arsenic, and radioactive radium (37, 94, 95)....
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TL;DR: In this paper, the authors highlight characteristics of produced water in detail and physical, chemical, and biological techniques used for its treatment, and reuse of produced waters for different purposes has been discussed.
Abstract: In oil and gas industry, produced water is considered as the largest waste stream, which contains relatively higher concentration of hydrocarbons, heavy metals and other pollutants. Due to the increase in industrial activities, the generation of produced water has increased all over the world and its treatment for reuse is now important from environmental perspective. Treatment of produced water can be done through various methods including physical (membrane filtration, adsorption etc.), chemical (precipitation, oxidation), and biological (activated sludge, biological aerated filters and others) methods. This paper aims to highlight characteristics of produced water in detail and physical, chemical, and biological techniques used for its treatment. In addition, reuse of produced water for different purposes has been discussed. At the end, few case studies from different countries, related to the treatment and reuse of their produced waters have been included.
327 citations
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TL;DR: Major research efforts in the future could focus on the optimization of current technologies and use of combined physico-chemical and/or biological treatment of produced water in order to comply with reuse and discharge limits.
1,862 citations
TL;DR: In this article, the authors evaluate the greenhouse gas footprint of natural gas obtained by high-volume hydraulic fracturing from shale formations, focusing on methane emissions, and find that 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the life time of a well.
Abstract: We evaluate the greenhouse gas footprint of natural gas obtained by high- volume hydraulic fracturing from shale formations, focusing on methane emissions. Natural gas is composed largely of methane, and 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the life- time of a well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following the fracturing. Methane is a powerful greenhouse gas, with a global warming potential that is far greater than that of carbon dioxide, particularly over the time horizon of the first few decades following emission. Methane contributes substantially to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The footprint for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years. Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years.
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TL;DR: Water management has emerged as a critical issue in the development of these inland gas reservoirs, where hydraulic fracturing is used to liberate the gas as discussed by the authors, where large volumes of water containing very high concentrations of total dissolved solids (TDS) return to the surface.
Abstract: Development of unconventional, onshore natural gas resources in deep shales is rapidly expanding to meet global energy needs. Water management has emerged as a critical issue in the development of these inland gas reservoirs, where hydraulic fracturing is used to liberate the gas. Following hydraulic fracturing, large volumes of water containing very high concentrations of total dissolved solids (TDS) return to the surface. The TDS concentration in this wastewater, also known as “flowback,” can reach 5 times that of sea water. Wastewaters that contain high TDS levels are challenging and costly to treat. Economical production of shale gas resources will require creative management of flowback to ensure protection of groundwater and surface water resources. Currently, deep-well injection is the primary means of management. However, in many areas where shale gas production will be abundant, deep-well injection sites are not available. With global concerns over the quality and quantity of fresh water, novel water management strategies and treatment technologies that will enable environmentally sustainable and economically feasible natural gas extraction will be critical for the development of this vast energy source.
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TL;DR: Tapping the lucrative Marcellus Shale natural gas deposits may have a host of environmental concerns, according to a report by the USGS.
Abstract: Tapping the lucrative Marcellus Shale natural gas deposits may have a host of environmental concerns.
585 citations
01 Jan 2010
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