Elucidating water contamination by fracturingfluids and formation waters from gas wells:fluidsandformationwatersfromgaswells:integrating isotopic and geochemical tracersA V h N th i l WEPA workshop onfracturing fluid composition,February 2011AvnerVengosh,NathanielWarner,Stephen Osborn, Rob JacksonFebruary2011Nicholas School of the Environment,Duke UniversityShale basins in the USAThe Marcellus shaleTheMarcellusshaleTracing fracturing fluids and co-producedformation watersDisposal to surface waterDisposaltosurfacewaterDeep water displacementNature of geochemical and isotopic tracersiδ18O,δ2HWaterisotopesWater chemistry(geochemicalfingerprinting)Isotopes of dissolved constituents(11B/10B,87Sr,86Sr,238U/234U,228Ra/226Ra)(1. Conservative versus non-conservative tracers2. Sensitivity to mixing, dilution effectsThe objective of this talk:Evaluate the potential and applicability of differentgeochemical and isotopic tracers for tracing the impacts offracturingfluids and coproduced waters on water resourcesGas well, Dimock, PAThe research methods:Duke Research activities (updated February 2011):1. Sampling ~70 shallow private wells in eastern PA, NY;2. Sampling 2 producing wells from PA and NY;3. Analysis of brines from the Marcellus Shale;3.AnalysisofbrinesfromtheMarcellusShale;4. Analysis of flowback effluents from a Marcellus gas well(provided by USGS);3 Ch i l ( j d t l t ) d i t i (87S /86Sδ11B3.Chemical(major andtrace elements)andisotopic(87Sr/86Sr,δ,δ18O,δ2H) measurements.Upper Devonian CatskillTriton@DukeNIST SRM 987 Sr standard30NISTSRM987Srstandard25152010Mean = 0.7102465ST= 9.31x10-6(0.01 per-mil)n=9800.71022 0.71023 0.71024 0.71025 0.7102687Sr/86Sr ratiohttp://www.nicholas.duke.edu/tims/Triton@D keNIST SRM-951 boric acid6070Triton@Duke5060Mean = 4.0051ST= 0.0026 (0.6 per-mil)n=2383040200103.999 4.001 4.003 4.005 4.007 4.00911B/10B ratiohttp://www.nicholas.duke.edu/tims/80Chemistry of background groundwater: Catskillif70Catskill Fmaquer5060

m g/L)Duke sampling1980s data*3040

d ium ( m20

So0100 10 20 30 40 50 60 70 80* Taylor LE (1984) Groundwater Resources ofthe Upper Susquehanna River Basin,Pennsylvania (Pennsylvania Department ofChloride (mg/L)Pennsylvania(PennsylvaniaDepartmentofEnvironmental Resources-Office of Parks andForestry - Bureau of Topographic and GeologicSurvey Water Resources Report 58).First indication for contamination by fracturingfluids and co-produced formation water:salinity100000Appalachianbrinesfluidsandco-producedformationwater:salinity10000pp c b es(Osborn data)

L )1000

m (mg/100

Sodiu10Catskill Fm10 1 10 100 1000 10000 100000 1000000Chloride (mg/L)Multiple salinity sourcesRoad salt deicingDomestic waste water,Acid-mine drainageSeptic tanksWater salinizationNatural salinegroundwaterM ll b iCoal ash leachatesFracking fluidsMacellusbrinesMultiple salinity sources with distinguished chemical compositionsRoad salt deicingDomestic waste waterAcid-mine drainageSeptic tanksNa-Cl water typeNa/Cl=1Na-Cl water type/ lh hCa-SO4water typeB/Cl-high low pHNa/Cl 1,Br/Cl, B/Cl-lowNa/Cl≥1, NO3-highBr/Cl-low, B/Cl-highB/Clhigh,lowpHCoal ash leachatesFracking fluidsMacellus brinesCSOt ta-4watertypeHigh Ca, pHB/Cl- very highCa-Cl water typeNa/Cl<1,Br/Cl,B/Cl-highHigh Ca, Sr, B, Ba/Cl, /Cl?The water isotopes-58Castskill FmCatskill Formation-62-60LMWL-64

δ

2 H-6670-68--11 -10.5 -10 -9.5 -9δ18OIndication for flowback and formation waters:E ih t f18O d2H dl l-30AppalachianbrinesEnrichmentof18Oand2H, andalower slope-40-35slope~3pp c b es(Osborn data)-50-45

2 Hslope360-55

δ

2C t kill F-65-60CastskillFmSlope ~8-70-10 -8 -6 -4 -2 0δ18OMinor and trace elements60200501503040

o n ( μ g/L)100

u m ( μ g/L)1020

Bor o50

Bari u00 10 20 30 40 50Lithium (μg/L)00 100 200 300 400 500 600 700 800Strontium (μg/L)Lithium(μg/L)Strontium(Flowback effluents mixed with Marcellusbi (M d #4 DOE/USGS li )160000017000001800000

L )6000070000

L )brines(Meadows#4,DOE/USGSsampling)12000001300000140000015000001600000

n tium ( μ g/ L300004000050000

o ron ( μ g/ L18000001000000110000012000000 5 10 15 20 25

Stro n1000020000-5 0 5 10 15 20 25

B o8000014000001600000

m ( μ g/L)6000070000

m ( μ g/L)80000010000001200000

Bariu m300004000050000

Lithiu m0 5 10 15 20 25300000 5 10 15 20 25Flow time (days)Strontium isotopes0 71550.7160Catskill Formation0.71500.7155

i osCatskillFormation0.71400.7145

8 6 Sr rat i0.71300.7135

87 Sr/

80.71250 200 400 600 800 1000Strontium (μg/L)Elucidatingbetween mixed fracturing-formation0.71200g gwaters and the Marcellus brines0.71150 8 6 Sr ratioMarcellus Shale200 711200.71140Marcellus Shale0.71100 87 Sr/

8Day2020%50%0.710800.711000.71120

r /

86 Sr0.710500.710200.710400.71060

87 S rF ki fl idFracturing fluids0.710000 500000 1000000 1500000 2000000 2500000Day 0Strontium (μg/L)Fracking fluids0.710000 5 10 15 20 25FrackingfluidsSampling dayFracturingfluidsFracturing fluidsStrontium(μg/L)Strontium isotopes: a sensitive tracer for mixingwith fracturing fluids/flowback water0.71600withfracturingfluids/flowbackwater0.714000.71500Catskill Fm

a tio0.71300

r /

86 Sr r a0.71200Marcellus Shale

87 S r0 710000.71100Utica ShaleFrackingfluid(day0)A lower87Sr/87Sr for0.7100010 100 1000 10000 100000 1000000 10000000g ( y)Strontium (μg/L)non-mixed fracturingfluidsThe sensitivity of strontium isotopes to mixing withfracturingfluids and backflow brines0 713000.713500.712500.71300Catskill Fm groundwater0 11 00.71200

S r/

86 Sr0.711000.71150

87 SMarcellus Shale0 710000.71050Fracking fluid (day 0)Fracturing fluids-formation water mix0.7100010-1010-810-610-410-2100Fraction of contaminated waterBoron isotopes30Catskill aquifer25

m il)20

B (permδ11B ={( [11B/10B]sample/[11B/10B]STD} -1} x100015

δ

11 BSTD=NIST SRM-951 boric acid100 100 200 300 400 500Boron (μg/L)Boron isotopes: differentiation from othercontaminant sources35Marcellus Shalecontaminantsources30

i l)Fracking+ MarcellusFlowback fluids25

(per-m igmixFlowbackfluids20

δ

11 BDomestic waste water;δ11B~0-10 per mil1015Domesticwastewater;δB 010permilCoal, coal ash;δ11B~-15-0 per mil101 10 100 1000 10000 100000Boron (μg/L)Boron isotopes: differentiation from othercontaminant sourcescontaminantsources40Marcellus shale2030

i l)Catskill groundwaterFracturing+brines mix10

(per-m iDomestic wastewater0

δ

11 B20-10Coal, coal ash leaching-0 0.01 0.01 0.02 0.02 0.031/B (L/mg)Tracing the impacts of gas-well drilling andfracturing fluids fluids on water resourcesfracturingfluidsfluidsonwaterresourcesMajorchemistryMinor andtrace elementsWater isotopesδ18O,δ2H87Sr/86Srδ11B228Ra/226Ra222RnThe key points:1)Integration of multiple tracers;2)Establish geochemical and isotopic baseline forbackgroundgroundwater prior togas drilling