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