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Hydraulic Fracturing and Groundwater Q uality. Zacariah L. Hildenbrand, Ph.D. Inform Environmental, LLC 6060 N. Central Expressway, Suite 500, Dallas, TX 75206. Lots of opinion but is there any data?. Elevated levels of methane - PowerPoint PPT Presentation
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Zacariah L. Hildenbrand, Ph.D. Inform Environmental, LLC
6060 N. Central Expressway, Suite 500, Dallas, TX 75206
Hydraulic Fracturing and Groundwater Quality
Lots of opinion but is there any data?
S.G. Osborn., et al. Proc. Natl. Acad. Sci. 2011, 108, 8172-8176.
Elevated levels of methane
Geospatial relationship between methane concentration and distance to neighboring gas well
Evidence of deep thermogenic methane contamination
Hydraulic Fracturing
Shale Acidization
Underground Injection Wells (Waste disposal)
What is unconventional drilling?
What is Hydraulic
Fracturing?
Hydraulic Fracturing
Shale Acidization
-HCl and/or HF acid
Underground Injection Wells (Waste disposal)
What is unconventional drilling?
Hydraulic Fracturing
Shale Acidization
-HCl and/or HF acid
Underground Injection Wells (Salt Water Disposal)
What is unconventional drilling?
www.brincowater.com
Where is this occurring?
Environmental ConcernsEarthquakesCleburne, Irving, Azle, Dallas, OK, AR, Japan
USGS has evidence that underground waste injection can cause small scale earthquakes
Surface water contaminationWaste pits, fluid spills, pipeline leaks
Groundwater contaminationWaste pits, faulty casings
Is there a hydrologic connection to deep fractures?
Waste Management?
Environmental ConcernsEarthquakesCleburne, Irving, Azle, Dallas, OK,AR, Japan
USGS has evidence that underground waste injection can cause small scale earthquakes
Surface water contaminationWaste pits, fluid spills, pipeline leaks
Groundwater contaminationWaste pits, faulty casings
Is there a hydrologic connection to deep fractures?
T. Darrah et al., 2014. Proceedings of the National Academy of Sciences
Composition of Fracturing fluidWater (up to 99%, 3-5 million gallons per well)
Chemical additives (up to 2%)*Biocides, surfactants, gelling agents, emulsifiers, corrosion inhibitors, BTEX compounds (benzene, toluene, ethylbenzene, xylene)*Exact recipe is proprietary to each company although information is available at www.fracfocus.org
Proppants (sand and/or ceramics)
Large quantities of HCl/HF (shale acidization)
Fate of fracturing fluids?10-30% of flowback water is recovered
Flowback and produced waters are contaminatedTotal Dissolved Solids (TDS), chlorides, Naturally Occurring Radioactive Material (NORM), chemical additives
Flowback can be:Placed in containment pits, treated at wastewater plants, stored in underground injection wells or recycled (many new technologies are emerging)
How Do We Determine if Hydraulic Fracturing is Affecting Groundwater?
Baseline measurements are incredibly valuable in assessing the anthropogenic effects of unconventional drilling
Scheduled monitoring can identify changes/fluctuations in groundwater quality
Advanced analytical tools are available to detect the occurrence of contamination events that may be directly or indirectly attributed to unconventional drilling activity
In situ Basic Water Quality Analyses
pH
Total Dissolved Solids (TDS)
Salinity
Conductance
Temperature
Dissolved Oxygen (DO)
Oxidation Reduction Potential (ORP)
Developed Methodologies
Methanol
Ethanol
n-propanol
Isopropanol
n-Butanol
2-Ethylhexanol
2-Butoxy Ethanol
Propargyl Alcohol
Benzene
Toluene
Phenol
Benzylchloride
Ethylbenzene
0-, m-, & p-Xylenes
1,2,4-Trimethyl Benzene
1,3,5-Trimethyl Benzene
Isopropyl Benzene
d-Limonene
Naphthalene
1-Methyl Naphthalene
2-Methyl Naphthalene
1-Naphthol
2-Naphthol
Ethylene Glycol
Polyethylene Glycol
Propylene Glycol
Dichloromethane
PEG 200
Glycerol
Acetophenone
Dimethylformamide
Glutaraldehyde
Acetaldehyde
Di(2-Ethylhexyl) Phthalate
Pthalic Anhydride
Bisphenol A
Gas Chromatography Mass Spectrometry (GC-MS)Head Space Gas Chromatography (HS-GC)
Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES)
Quantification of 70+ minerals and metals
Elevated Levels of Arsenic
29 of the 91 samples collected with active extraction areas contained elevated levels of arsenic (>10 μg/L)
Highest concentration that was detected was 161 μg/L
Arsenic was not found to be elevated in any of the control sites
B.E. Fontenot, et al. Environ. Sci. Tech. 2013, 47, 10032-10040.
Geospatial analysis of TDS and Arsenic
B.E. Fontenot, et al. Environ. Sci. Tech. 2013, 47, 10032-10040.
Geospatial analysis of Selenium and Strontium
B.E. Fontenot, et al. Environ. Sci. Tech. 2013, 47, 10032-10040.
Comparison to historical data
B.E. Fontenot, et al. Environ. Sci. Tech. 2013, 47, 10032-10040.
Geospatial analysis of TDS and Arsenic
B.E. Fontenot, et al. Environ. Sci. Tech. 2013, 47, 10032-10040.
Sampling bias?
B.E. Fontenot, et al. Environ. Sci. Tech. 2014
10μg/L
10μg/L
ConclusionsInstances of arsenic contamination are highest near hydraulic fracturing sitesCould be through direct mechanisms, although GC-MS results indicate that this is unlikely (pipeline/casing blowouts, improper handling of hydraulic fracturing wastes)
Could be through indirect mechanisms (liberation of heavy metal ions from scale/rust in poorly maintained wells)
More data needs to be collectedNeed to cover more area with a greater sampling size
Time-lapse analysis before, during and after drilling
2014 Study#Data points 550
Collin 4
Cooke 40Dallas 1
Denton 82Ellis 25Hill 14
Hood 60Johnson 43
Montague 66Parker 108
Somervell 19Tarrant 47
Wise 41
#Residential wells 350#Municipal/Public Water
supply wells 141#Agricultural wells 59 Z.L. Hildenbrand, et al. unpublished1
Eagle Ford Shale
60+ groundwater samples collected to date; on pace for over 200 throughout the Eagle Ford Shale region.
Z.L. Hildenbrand, et al. unpublished2
Time-lapse analyses in the Cline ShaleNOLAN COUNTY SCURRY COUNTY
40+ samples collected before, during and after unconventional drilling in the Cline Shale of west Texas.
A B
Z.L. Hildenbrand, et al. unpublished3
Future DirectionsExpand our reach into other shale formationsHaynesville, Wolfcamp/Wolfberry, Woodford, and Palo Duro
Become more involved into other components of the unconventional drilling process and other industrial processesUse our advanced analytical capabilities to characterize a wide range of environmental events/catastrophes
Develop new technology and best management practices for instances of drilling-related contamination eventsRemediation, recycling, appropriate waste disposal