epa listening tour currently underway in us regarding the threat that hydraulic fracturing may pose to groundwater
see for eg, "EPA Weighs Risks of Hydraulic Fracturing for Natural Gas", NYT, 23/07/10 [not reproduced in full, with link provided to enable forum members to read full story at NYT website]
http://www.nytimes.com/2010/07/24/business/energy-environment/24gas.html?ref=business&pagewanted=all
The streams of people came to to the public meeting here armed with stories of yellowed and foul-smelling well water, deformed livestock, poisoned fish and itchy skin. The culprit, these people argued, was hydraulic fracturing, a method of extracting natural gas that involves blasting underground rock with a cocktail of water, sand and chemicals.
Gas companies countered that the horror stories described in Pennsylvania and at other meetings held recently in Texas and Colorado are either fictions or not the companies' fault.
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Roughly 99.5 percent of the fluids typically used in fracking, the indutry says, are just water and sand, with trace elements of chemical thickeners, lubricants and other compounds added to help the process along. The cocktail is injected thousands of feet below the water table and, the inductry argues, can't possibly be responsible for growing complaints of spoiled streams and wells. But critics say that the relationship between fracking fluids and groundwater contamination has never been thoroughly studied - and that proving a link has been made more difficult by oil and gas companies that have jealously guarded as trade secrets the exact chemical ingredients used at each well.
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Fears of fracking's impact on water supllies prompted regulators overseeing the Delaware Water Basin to curtail gas exploration until the effects could be more closely studied. New York State lawmakers are contemplating a moratorium. At he national level, in addition to the EPA study, a Congressional investigation of gas drilling and fracturing, led by House Energy and Commerce Committee, intensified last week with demands sent to several companies for details on their operations - particularly how they handled the slurry of water and chemicals that flowed back from deep within a well.
A renewed, if unlikely, push is also under way to pass federal legislation that would undo an exemption introduced under the Bush administration that critics say freed hydraulic fracturing from regulation under the Safe Drinking Water Act.
Last month, Wyoming introduced some of the nation's toughest rules governing fracturing, including provisions that require companies to disclose the ingredients in their fracturing fluids to state regulators - though specifically not to the public.
Gas drillers, responding to the incresed scrutiny and eyeing the expansive and lucrative new gas plays in Appalachia, are redoubling their efforts to stave off federal oversight, in some cases by softening their rigid positions on fracking-fluid disclosure. Last week, Range Resources went so far as to announce its intent to disclose the contents of its fracking fluids to Pennsylvania regulators and to publish them on the company's website.
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as to the EPA study
as annd in the Federal Register Vol 75, No 118, Mon 06/21/10
The EPA is announcing four public meetings to explain its proposed plan to study the relationship between hydraulic fracturing and drinking water.
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The Hydraulic Fracturing Study informational meetings are as follows: July 8, 2010, in Fort Worth, Texas; July 13, 2010, in Denver, Colorado; July 22, 2010, in Canonsburg, Pennsylvania; August 12, 2010, in Binghamton, New York.
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The meetings are open to the public and all interested stakeholders are invited to attend. Presentations by EPA will be limited to study planning and will not include discussions on hydraulic fracturing policy or past EPA studies.
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The meetings will begin with brief presentations by the EPA Office of Research and Development on hydraulic fracturing ... Oral comment session will begin after the presentation, and oral comments will be limited to two minutes each. [comments may also be submitted in writing at information sessions or to EPA contact address]
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EPA study timeline (taken from EPA Hydraulic Fracturing Study Federal Partner Consultation preso dated 05/27/10, p8)
05-06/10 State & Federal Partner meetings
06/10 website posted
07-08/10 Public meetings
09/10 Draft Study Design Final
10-11/10 Technical Workshops
10/10 Peer Review
01/11 initiate Study
late /12 initial results expected
as to fracking fluid makeup (from "Modern Shale Gas Development in the United States: A Primer, US Dept of Energy, Office of Fossil Energy National Energy Technology Laboratory, April 2009, p 61)
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The fracturing fluids used for shale gas stimulations consist primarily of water but also include a variety of additives. The number of chemical additives used in typical fracture treatment varies on the conditions of the specific well being fractured. A typical fracture treatment will use very low concentrations of between 3 and 12 additive chemicals depending on the characteristics of the water and the shale formation being fractured. Each component serves a specific, engineered purpose. The predominant fluids currently being used for fracture treatments in the gas shale plays are water-based fracturing fluids mixed with friction-reducing additives (called silckwater).
The addition of friction reducers allows fracturing fluids and proppant to be pumped to the target zone at a higher rate and reduced pressure than if water alone were used. In addition to friction reducers, other additives include: biocides to prevent microorganism growth and to reduce biofouling of the fractures; oxygen scavengers and other stabilizers to prevent corrosion of metal pipes; and acids that are used to remove drilling mud damage within the near-wellbore area. These fluids are used not only to create the fractures in the formation but also to carry a propping agent (typically silica sand) which is deposited in the induced fractures.
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an inductry fact sheet ("A Fluid Situation: Typical Solution* used in Hydraulic Fracturing" from
www.energyindepth.org) lists the fracturing fluids as
99.51% water and sand;
0.49% additives, comprising
-acids 0.123% (helps dissolve minerals and initiate fissure in rock - pre-fracture);
-glutaraldehyde 0.001% (eliminates bacteria in the water);
-sodium chloride 0.01% (allows delayed breakdown of the gel polymer chains);
-N, n-Dimethyl formamide 0.002% (prevents corrosion of the pipe);
-borate salts 0.007% (maintains fluid viscosity as temp increases);
-polyacylamide (minimizes friction between fluid and pipe);
-petroleum distillates 0.088% ('slicks' water to minimize friction);
-guar gum 0.056% (thickens water to suspend the sand);
-citric acid 0.004% (prevents precipitation of metal oxides);
-potassium chloride 0.06% (creates brine carrier fluid);
-ammonium bisulfite (removes O2 from H20 tp protect pipe from corrosion);
-sodium or potassiom carbonate 0.011% (maintains effectiveness of other components);
-proppant (allows fissure to remain open so gas can escape);
-ethylene glycol 0.043% (prevents scale deposits in pipe);
-isopropanol 0.085% (increases viscosity of fracture fluid)
the above info is sourced (according to factsheet) from the aforementioned Gas Shale Primer, supra
however, again from p 61 of the Primer
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Overall the concentration of additives in most slickwater fracturing fluids is a relatively consistent 0.5% to 2% with water making up 98% to 99.5%.
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the example of the makeup of a typical fracturing fluid (0.49% aditives) in both the industry factsheet and the Primer is below the 'relatively consistent' 0.5-2.0% in 'most slickwater fracturing fluids'