3. TERMINOLOGY: LIQUIDS
• Makeup water-impoundments/tanks
– fresh water
– waste water
• Hydraulic fracturing fluid-frac fluid
~ 100,000 to 120,000 bbl injected
– Makeup water +
– Proprietary mixture of chemicals
– Proppant
• Flowback-produced water
Fluids returned from the well after frac
~70-90% lost in formation
• Recycle
– Flowback-produced water used for makeup
4. FLUIDS AT THE WELL SITE
If major local well
completions:
Hydrofracing is a net
consumer of water
If not: then about
5. PRODUCED WATER
PROFILE
Flowback ^Q ^Q
day (bbl/day) (gpm)
1 4711 137
30 392 11
60 236 7
90 176 5
180 106 3
360 64 2
The decline in produced water returns varies from well
to well, not well documented out to 10 years
9. Cation:Cl ion pairs dominate in FPW
equivalents
ion pairs? PA well WV well
Sr SrCl2 114.2 50.2
Mg MgCl2 160.5 250.2
K KCl 99.7 176.5
Na CaCL2 2,756.5 1,487.0
Ca NaCl 1,177.1 1,835.4
cation sum 4,308.0 3,799.3
Cl 4,197.2 3,526.8
% Cl 103% 108%
10. IN FPW CHLORIDE IS THE DOMINANT ANION:
SOLUBILITY VS. SULFATE AND CARBONATE MINERALS
13. EVIDENCE THAT SULFATE PRECIPITATES
TO FORM SCALE
2,920 mg SO4 in HF fluid 11 mg SO4 in HF fluid
If this SO4 precipitated as
SrSO4, it would form 4 t/day of
scale over the first week
14. WATER TREATMENT TECHNOLOGIES
FALL INTO SIX MAIN CATEGORIES:
treatment
1. Bulk filtration
2. Lime softening
3. Sulfate addition
4. Nano filtration
5. Reverse osmosis
6. Evaporation/
Crystallization
removes
1. suspended solids
2. Mg, Ca –as carbonates
3. Sr, Ba, Ra- as sulfates
4. multivalent ions: Fe, Mg, Ca,
Sr, Ba, SO4
5. All ions
6. All inorganic ions
15. COSTS
INCREASE
FROM LEFT TO
RIGHT
Treatment end points
Sulfate addition
Nanofiltration
Reverse osmosis
Costs:
pre treatment
solids disposal
transportation
disposal fee
Bulk filtration:
TSS/Organics
surface dischargerecycle Deep well
injection
Bulk filtration:
TSS/Organics
Bulk filtration:
TSS/Organics
Lime softening
Evaporation/
Crystalization
Costs:
transportation
solids disposal
Costs:
astronomical
Do not over
treat your
water
16. SUMMARY
• Shale gas development creates large volumes of
contaminated waste water
• Pollutants include inorganic and organic
constituents
• Most flowback water is recycled
• Recycling is contingent on nearby well development
• Need efficient treatment for end of life cycle waste
water
17. TERMINOLOGY: SOLID WASTES
• Drilling mud
– Returns to the surface with cuttings during drilling
– Recycled after cuttings removed
– To disposal after well completed
• Drill cuttings
– Rock fragments-clay to fine gravel
– ~500-800 tons/well or 25 to 50 truckloads
– To disposal after separation from drilling mud
• Flowback Solids-filter cake, precipitates, suspended solids
23. FLOWBACK SOLIDS
ARE MORE
RADIOACTIVE THAN
VERTICAL DRILLING
MUDS/CUTTINGS:
BUT IS THE
DIFFERENCE
SIGNIFICANT?
Vertical only Marcellus
Drilling mud solid
samples
Flowback
solids
Solids units average Donna C pit
Gross Alpha pCi/g 17.35 65.10
Gross Beta pCi/g 25.22 28.80
Potassium-40 pCi/g 24.51 19.69
Radium-226 pCi/g 1.22 26.95
Radium-228 pCi/g 1.33 5.12
Thorium-228 pCi/g 1.23 2.33
Thorium-230 pCi/g 1.01 1.10
Thorium-232 pCi/g 0.90 1.11
Uranium-234 pCi/g 0.91 1.08
Uranium-235 pCi/g 0.03 0.07
Uranium-238 pCi/g 0.85 0.69
Alpha + beta pCi/g 42.6 93.9
gamma pCi/g 32.0 58.2
Total pCi/g 74.6 152.1
24. POTENTIAL EXPOSURE PATHWAYS:
• Migration from horizontal leg to
surface/shallow groundwater
• Poor casing/cement integrity
• Handling failures at the drill pad
• Fires, tank ruptures
• Pit and tank leakage
• Flowback transportation-truck
accidents, pipeline failures
25. EXPOSURE
PATHWAYS
A. JUDGING BY THE PRESS, YOU
MIGHT THINK THAT THE PRIMARY
RISK INVOLVES MIGRATION OF FRAC
FLUID TO A DOMESTIC AQUIFER.
B. SHALLOW AQUIFER
CONTAMINATION FROM BAD CASING
IS MORE LIKELY TO OCCUR.
maybe
doubtful
A
B
26. Domestic
well ~30 m
Well site spills
and pit leakage
Flowback pit
Spring
Well
MOST LIKELY HUMAN/ENVIRONMENTAL
EXPOSURE PATHWAYS
Casing/cement
failure
Volatile organics
28. MSEEL ENVIRONMENTAL STUDY
Background
• Funding: USDOE/NETL,
Northeast Natural Energy
Inc.
• WVU prime, OSU sub
• Begin April 2015
• Two wells installed in 2010
• Project will study two new
horizontal wells
• Test bed for new
technologies
Environmental objectives
• Reduce environmental
uncertainty and improve
environmental performance
• Characterize:
– Air emissions
– Liquid and Solid wastes
• Organic
• Inorganic
• Radiologicals
29. RECOMMENDATIONS: REDUCING
ACCIDENTAL RELEASES OF FPW
• Recycle/reuse flowback and produced water for frac water
makeup
• On site containment:
– Production casing integrity-testing prior to well completion
– Drill pad-lined and bermed
– Pits-construction/design/inspection according to State standards
– Flowback lines to be properly installed/protected
• Transportation:
– Tracking and accountability
• Solid waste characterization and disposal according to protective
standards (RCRA?)
30. FOR MORE INFORMATION
PLEASE CONTACT:
Paul Ziemkiewicz, Director
WVU Water Research Institute
304 293 6958
pziemkie@wvu.edu