Comparison of Hydraulic Fracturing Fluids Composition 

Produced Formation Water following Fracturing –Im

p p lications for Fate and Trans

port

Debby McElreathOklahoma City OklaOklahoma City, Okla
Presentation Outline

IntroductionPredicted Fate and Transport of Hydraulic Fracture ChemicalsF t E l ti F

a

t

e Evaluation

- C i f P di t d Comparisons

of Predi

c

t

ed 

Concentrations with Measured Concentrations Indicator ParametersTransport Evaluation – Selected RadionuclideConclusions
Chesapeake Energy Operating Areas
Presentation Outline

IntroductionPredicted Fate and Transport of Hydraulic Fracture ChemicalsF t E l ti F

a

t

e Evaluation

- C i f P di t d Comparisons

of Predi

c

t

ed 

Concentrations with Measured Concentrations Indicator ParametersTransport Evaluation – Selected RadionuclideConclusions
Predicted Downhole Fate for Hydraulic 

Fracturing Fluid Components

HF Fluid Component Predicted Downhole Fate

A

cid

Reacts with min

erals to

create salts, water a

n

d CO2 c d eacts t e a s to c eate sa ts, ate a d CO

Corrosion Inhibitor Bonds with pipe surfaces, broken down by micro-organisms or re

produced formation water

Iron Control Reacts with minerals to create salts, water and CO2

Broken down by micro-organisms or small amount returned in fo

Anti-Bacterial Agent water

Scale Inhibitor Attaches to the formation; majority returns with produced format

Friction Reducer Remains in formation; broken down by micro-organisms or small 

in formation produced water

Surfactant Returned with produced formation water or produced natural gas

Gelling Agent Broken down by breaker and returns with produced formation wa

Breaker Reacts with “gel” and “crosslinker” to form ammonia and sulfate 

returned in produced formation water

Crosslinker Combines with the “breaker” in the formation to create salts that 

produced formation water
Fate and Transport of Components in 

Fracturing Fluids

Elevated temperatures and pressure as well as the interactions fluid itself changes the form of most componentsReactions between hydraulic fracturing fluid components and/formation produce constituents which can be measured as sursalts, sulfates, nitrogen compounds, etc., using accepted analymethods

Salts can be measured as Total Dissolved SolidsSulfatesNitrogenous compounds – Total Kjeldahl Nitrogen and Ammonia used as s

Often can not measure for the chemical itself, can only measuindividual pieces

KCl – can not easily measure KCl but instead measure Potassium and ChSodium Hydroxide – measure Sodium as an indicator

The matrix of fracturing fluids are products rather than typical environmental samples, therefore holding times, etc. are not va
Presentation Outline

IntroductionPredicted Fate and Transport of Hydraulic Fracture ChemicalsFate Evaluation 

- Comparisons of Predicted 

Concentrations with Measured ConcentrationIndicator ParametersTransport Evaluation – Selected RadionuclideConclusions
Data Evaluated

Vendor supplied information regarding quantity of hydraufluids usedMixed hydraulic fracturing fluidsP d d f ti t ft h d li f t i g ti Produced formation water after hydraulic fracturing activ

Iterative samples over time

Analy gp tical results available for the following parameters:

Volatile organics, including glycols Semi-volatile organicsMetals total and dissolved Metals, total and dissolvedGeneral chemistryRadiochemistry (gross alpha/beta, Radium 226/228, and some isotopic nuclides by gamma spectroscopy)
Produced Formation Water Production

Volumes – Location 1 (Western U.S.)

Comparison of Typical Annual Produced Water Volume: First year after Comple(Days 1-10 & 11-365) and Subsequent Years of Production

lume (gal) Increasing Vo
Hydraulic Fracture Fluid Components used

in Location 1 – Western U.S.

Acid – hydrochloric acidCorrosion and Scale Inhibitors – alcohols, organic acid and polsodium saltIron Control – sodium compoundBiocide – gluteraldehyde and an alcoholFriction Reducer - polymer and hydrocarbonBreaker – ammonium persulfateCrosslinker

– polyol and borax
Summary of Analytical Results

Selected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 30 Days)Location 1 - Western U.S.

Parameter

H

ydraulic

Concentrations in Produced Formation Water following Hydraulic 

Time (mg/L)

Parameter

y

Fracture Fluid

6 Hours Day

1

(24 Hours) Day 2 Day 9 

Total KjeldahlNitro

gen 41.3 523 3,770 5,200 315 

Ammonia 38.5 110 140 201 273 

Chloride 126 16,500 25,500 39,600 46,500 

Sulfate Sulfate 162 91.6 82.1 28.8 31.6 

Total Dissolved

Solids 1,500 39,300 54,100 68,300 140,000 

Sodium 94.9 7,260 10,800 14,700 27,100 

Boron 0.0785 0.075 17.5 20.6 28.8 

Benzene <1 4.15 6.34 11 7.69 

l

To uene 1.44 1.01 1.04 1.43 1.30 
Summary of Analytical Results

Selected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 30 Days)Location 1 - Western U.S.

Calculated

Concentrations in Prod

Formation Water following 

Parameter

Calculated

Concentration

In Hydraulic

Fracture Fluid

(μg/L)

Hydraulic

Fracture Fluid

Fracturing with Time (μ

(μg/L) 12 Hour D

Glycols 55,000 35,800 <10,000 <1
Concentration of Indicator Parameters and

Time after Hydraulic StimulationLocation 1 – Western U.S.

100000 00

1000000.00

1000.00

10000.00

100000.00

)

10.00

100.00

ncentration (mg/L 

0.101.00

Con

0.000.01

0 100 200 300 400 500 600 700 

Ti f H d li S i l i (h )Time after Hydraulic Stimulation (hours)
Produced Formation Water Production Volumes

Location 2 - Eastern U.S.

al) sing Volume (g Increa
Hydraulic Fracture Fluid Components used

in Location 2 - Eastern U.S.

Acid – hydrochloric acid Corrosion and Scale Inhibitors – alcohol, glycol, and amideIron Control 

– citric acid

Biocide – sodium salt, sodium hydroxide, and a bromide saltFriction Reducer – water soluble polymer (nitrogenous)Breaker – sodium and potassium saltsGel – guar gum, hydrocarbon, and polymerSf ur

factant

–

al h l l l d h d b lco

h

ol, glycol and h

y

drocar

bon
Summary of Analytical Results

Selected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 30 Days)Location 2 

– Eastern U S Eastern U.S.

Hydraulic

Concentrations in Produced Formation Water f

Hydraulic Fracturing with Time (mg/L)

Parameter Fracture

Fluid

6 Hours 12 Hours Day 5 Day 10 

Sulfate Sulfate 35 3. 86 <50 27 2. 8 9. 

Total Kjeldahl

Nitrogen 97.2 112 104 224 150 

Ammonia 9.62 39.3 42.5 70.2 60.9 

Chloride 2,790 31,200 30,800 78,300 6,0600 

Total Dissolved

Solids 7,700 39,400 43,200 94,300 119,000 

Sodium 793 7940 9570 19,500 26,200 

Benzene 77 64.7 129 625 797 

Toluene 198 62.6 554 833 1,540 Toluene 198 62.6 554 833 1,540 
Summary of Analytical Results

Selected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 5 Days)Location 2 - Eastern U.S.

Concentrations 

Formation Wat

Parameter

Calculated

Concentration in

Hydraulic Fracture

Fluid (μg/L)

Hydraulic Fracture

Fluid

Hydraulic Fract

Time (μ

12 Hours 

Glycols 6,000 1,080,000 17,100 

2‐Butoxyethanol Butoxyethanol 117 000 117,000 <10 000 <10,000 <10 000 <10,000 
Concentration of Indicator Parameters and

Time after Hydraulic StimulationLocation 2 – Eastern U.S.

100000

1000000

1000

10000

(mg/L) 

10

100

Concentration 

0.1

1

0.01

0 100 200 300 400 500 600 700 

Time After Hydraulic Stimulation (Hours)
Presentation Outline

IntroductionPredicted Fate and Transport of Hydraulic Fracture ChemicalsFate Evaluation - Comparisons of Predicted Concentrations with Measured Concentrations Indicator ParametersTransport Evaluation – Selected RadionuclidesConclusions
Transport of Radionuclides in 

Produced Formation Water

Presence of radionuclides in shale formation water is well docuAnalytical method of choice: EP Analytical method of choice: EPA Method 901 A Method 901 1 modified (Gam

.1 modified (Gam

Spectroscopy)

Less influenced by matrix interferences

Data must be reported with activity, accompanied by standard minimum detectable concentration (“MDC”)

Example: 970 

± 130 pCi/L (MDC 30 pCi/L) Radium-226

Focus should be on Radium-226 and Radium-228

Radium 226 and radium 228 represent more than 80% of tradiation dose in ingested water
Selected Total Radionuclide Data for Produced 

Formation WaterWestern U.S. 

Parameter Methods Units Minimum Maximum Mean

Error 

(±1 SD) 

RadioChemistry

Gross Alpha SW 9310 MOD; EPA 900.0 pCi/L 620 4,000 1,750 ±1,261 

Gross Beta SW 9310 MOD; EPA 900.0 pCi/L 250 1,200 760 ±392 

Radium 226 EPA 901.1 Mod. pCi/L 167 904 616 ±285 

Radium 228 EPA 901.1 Mod. pCi/L 101 459 329 ±139 Uranium 238 Uranium 238 EPA 901 1 Mod EPA 901.1 Mod. pCi/L Not Detected Not Detected Total Dissolved Solids mg/L 125,000 140,000 132,500 ±10,600 

MDC – Minimum Detectable Concentration 
Selected Radionuclides and 

Time After Hydraulic StimulationLocation 1 

– Western U.S.

100000

1000000

10000

on (mg/L)

100

1000

TDS Concentratio

10

1

0 100 200 300 400 500 600 700 80

Time after Hydraulic Stimulation (hours)
Selected Total Radionuclide Data for Produced 

Formation WaterEastern U.S. 

Parameter Methods Units Minimum Maximum Mean

Error

(± 1 SD

RadioChemistry

Gross Alpha

SW 9310 MOD; EPA 

900.0 pCi/L 4,100 6,600 5,350 ±1,767 

Gross Beta

SW 9310 MOD; EPA 

900.0 pCi/L ND 2,400 --- ±1,131 

Lead 210 EPA 901.1 Mod. pCi/L Not Detected 

Radium 226 EPA 901.1 Mod. pCi/L 867 1,050 959 ±129 

Radium 228 EPA 901.1 Mod. pCi/L 584 620 602 ±25 

Uranium 238 EPA 901.1 Mod. pCi/L Not Detected 

Total Dissolved Solids Mg/L 148,000 153,000 150,500 ±3,536 

MDC – Minimum Detectable Concentration
Selected Radionuclides and 

Time After Hydraulic StimulationLocation 2 – Eastern U.S.

100000

1000000

10000

on (mg/L)

100

1000

TDS Concentratio

10

1

0 100 200 300 400 500 600 700 80

Time After Hydraulic Stimulation (Hours)
Presentation Outline

IntroductionPredicted Fate and Transport of Hydraulic Fracture ChemicalsFate Evaluation - Comparisons of Predicted Concentrations with Measured ConcentrationIndicator ParametersTransport Evaluation – Selected RadionuclideConclusions
Conclusions

Produced formation waters variable within and between formationsThe elevated temperature aeffects the fate and transpohydraulic fracturing fluid comThe concentration of compoproduced formation water is produced water volumes
Conclusions

Most reliable sentinel compounds achloride and divalent cations becauthe highest concentrations in produwaterThe concentration of TDS is predictconcent ti f th th i tration of the other speciesThe concentrations of potential indiparameters in produced formation overshadowed by the naturally-occuconcentrations of these parameters watersThe presence of NORM is delayed awith higher percentages of producewater with time