Water Quality, Quantity, and Management: Lessons from the Marcellus Shale Region

Water Quality, Quantity, and
Management: Lessons from the
Marcellus Shale Region
Radisav D. Vidic, PhD, PE
Department of Civil and Environmental Engineering
University of Pittsburgh

civil and environmental engineering

Shale Gas Basins


Hydrofracturing


Water Supply Issues
• Need 2 to 6 Million gallons of water per well for hydraulic
fracturing
• Surface Water Withdrawals
– Concerns about depletion of water resources, especially in drought years
– Impacts to aquatic life
– Ability to get withdrawals approved
– Don’t really need high quality water, but consistent quality is important
• Transportation of water
– 1 MG = 200 trucks
– Cost can be significant (up to $2/bbl)
• Water storage on site


Water Withdrawal in PA
• Need 2 to 6 Million gallons of water per well for a multi-
stage hydrofracturing
Water-use category Water withdrawal Percentage
(MGD) (%)
Public supply 1420 15
Domestic 152 1.6
Irrigation 24.3 0.3
Livestock 61.8 0.6
Aquaculture 524 5.5
Industrial 770 8.1
Mining 95.7 1
Thermoelectric power plants 6430 67.7
Marcellus Shale exploitation in 2013 18.7 0.2
(Gaudlip et al. 2008)

Water Use in PA

Marcellus Shale Play is not a significant water user in PA

Water Transfer Issues
- Trucks
- Temporary surface lines
- Permanent subsurface lines


Water Storage Issues

Storage options:
• Centralized
impoundment—
now becoming
more prominent
• Single pad-
dedicated
impoundment
• Frac tanks

Storage based on
ultimate scale of
operations (long vs.
short term)


Volumetric Composition of Fracking Fluids


Fracture Fluid Composition
Additive type Main Compound Purpose

Diluted acid (15%) Hydrochloric or Dissolve minerals and initiates
Muriatic cracks in rock

Biocide Glutaraldehyde, DBNPA Bacterial control
Corrosion inhibitor N,n-dimethyl Prevents corrosion
formamide
Breaker Ammonium persulfate Delays breakdown of gel polymers

Crosslinker Borate salts Maintains fluid viscosity at high
temperature
Polyacrylamide Minimize friction between the
Friction reducers fluid and the pipe
Mineral oil

Gel Guar gum or Thickens water to suspend the
hydroxyethyl cellulose sand


Fracture Fluid Composition

Additive type Main Compound Purpose

Iron control Citric acid Prevent precipitation of metal
oxides
Oxygen scavenger Ammonium bisulfite Remove oxygen from fluid to
reduce pipe corrosion
pH adjustment Potassium or sodium Maintains effectiveness of other
carbonate compounds (e.g., crosslinker)
Proppant Silica quartz sand Keeps fractures open

Scale inhibitor Ethylene glycol Reduce deposition on pipe

Surfactant Isopropanol Increase viscosity of fluid


Latest Fracture Fluid Designs
Sand Additives
5.56% 0.08%

Water Additives
94.36% Anti-
Friction microbial
reducer 37%
50%

Scale
inhibitor
13%

Anatomy of
a Vertical Well

Marcellus Shale wells are cased
and grouted (using special
cements) to prevent migration of
natural gas and fluid from the
producing zone up the well bore
into fresh-water aquifers.


Wastewater Issues

Flowback water Produced water

Flowrate High Low (10-50 bbl/day)
Duration 1 – 2 weeks Life of the well
TDS < 200,000 mg/L > 300,000 mg/L
Chemical additives Same as flowback but more
Composition
Naturally occuring constituents salts
Water recovery
10 – 40 %
Flowrate varies
with location


Wastewater Storage Issues
Storage options:
• Centralized
impoundment
• Single pad-
dedicated
impoundment
• Frac tanks

Environmental Risks
- Leakage
- Erosion and sediment control


Flowback Water Characterization
160 flowback water analyses (BOGM, MSC, etc.)

3(1) 18(8)
14(10)
29(15) 29(15)
4(1) 2(1)
7(3)

2(2)

1(1)
26(4) 4(2)

1(1)

15(3)
23(5)

8(3)
3(3)


Flowback Water Quality
Constituent Low Medium High

Ba (mg/L) 2,300 3,310 13,500
Sr (mg/L) 1,390 2,100 8,460
Ca (mg/L) 5,140 14,100 41,000
Mg (mg/L) 438 938 2,550
Hardness (mg
17,900 49,400 90,337
/L as CaCO3)
TDS (mg/L) 69,400 175,600 345,000
Gross Beta
ND 43,415 597,000
(pCi/L)
Ra226 (pCi/L) ND 623 9,280
COD (mg/L) 850 12,550 36,600


Flowback Water Management

• Wastewater disposal
- Injection/disposal wells
- Disposal to dedicated treatment facilities
- Discharge to POTWs


Gas Drilling Wastewater Management

(Hart, P., 2011)

19

Disposal Wells
• Require demonstration that injected fluids remain
confined and isolated from fresh water aquifers
• Limited capacities (1200 to 3000 bpd)
• Substantial capital investment with uncertain life
span ($1M to $2M)
• Probably will only play a limited role
• Depleted shallower wells are currently being
evaluated!?!?


Microseismic Tests in Marcellus Shale


Dedicated Treatment Facilities


Impact on Surface Water Quality


Impact on Surface Water Quality

CROOKED CREEK & McKEE RUN
Bromide Concentration (ppb)
Oct Nov Dec Jan Feb March April May June July Aug Sept Oct
Sample Site
2010 2010 2010 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011
McKee Upstream of Plant B 29 79 61 36 27 17 32 66 93 63 26 25
Run Donwstream of Plant B 20 X 10 X 9X 10 X 1.1 X 3X 3X 8X 8X 27 X 34 X 4X 17X

Blue Spruce Bridge 57 39 64 87 37 38 13 53 83 116 114 56 25
Crooked
Creek Bridge St. Bridge 1130 345 639 774 42 111 44 414 640 3100 3900 214 427
Stitt Hil Rd. Bridge 280 467 396 173 74 53 112 258 578 582 426 103

(Casson, L., 2012)


Disposal to POTWs
• Chosen option in the past
• POTWs use biological processes
• Biological systems cannot handle high salinity
(few case studies above 35,000 mg/L)
• Require an approved pretreatment program


Treatment for Reuse in Fracking
Operations

• Reduce O&G industry needs for surface water
• Reduce overall management costs
– Volume reduction
– Transportation costs
– Disposal costs
• Reduce potential liability


Water Bank Concept

• Reuse difficult for smaller operators
– Insufficient well count
– Insufficient capital

• Develop rules for water banking
– Smaller operator dispose of their wastewater in
regional impoundments
– Larger operators get credit for water reuse and
pollution elimination

Recycling/Reuse
• 4800 wells on 625 mi2
• 3 refractures/well
• 33% water reuse

- Works for 12-15 yrs
- Eventually we are a
net producer of water

Total Water Balance Within a Gas Field

(Kujivenhoven et al., 2011)

29

Treatment Options
100
Crystallizers
Water Recovery (%)

Evaporation

75 Limited recovery
at high TDS

50

25,000 50,000 100,000 300,000
Total Dissolved Solids (mg/L)


Complete Treatment Process

FLOWBACK
WASTE
WATER FRAC BRINE
SOURCE OPERATIONS PRODUCED STORAGE
WATER

RECOVERED WATER Pretreatment

ROAD BRINE BRINE
DEICING CRYSTALLIZER CONCENTRATOR
Volume
SALT Reduction
Based on
TDS

PURGE TO
95% Volume
DISPOSAL
Reduction


Gas Drilling Wastewater Management

(Hart, P., 2011)

32

Salt production in Marcellus region
• 100,000 wells
• 10 barrels/day/well of produced water
• 300,000 mg/L salinity of produced water
• 80% salt recovery

• Total NaCl produced in PA = 8 million tons
• Total salt use for deicing in the US = 12-15 million tons


AMD in Pennsylvania
• Pennsylvania’s single greatest source of water pollution
– Contaminated 4,000 miles of streams
• Elevated levels of iron and sulfate
• Can have elevated hardness
• TDS typically around 1,000 mg/L

• May be suitable as fracking water make up with little or
no treatment


Why AMD?

Permitted wells Abandoned discharge Reclaimed discharge


Co-treatment of flowback water and AMD

Flowback water Abandoned mine
drainage (AMD)

Barium, Strontium, Calcium Sulfate

Hydraulic fracturing

Enables the reuse of flowback water for hydraulic fracturing with
limited treatment => decreases the treatment and transport cost
of flowback water

36

Summary
• Marcellus shale development hinges on
documenting environmental impacts and developing
sustainable water management
• Almost no direct disposal options and limited
treatment options for flowback/produced water
• Flowback water reuse appears to be the most
effective option
• Water reuse has a finite lifetime
• Salt management may become a major issue in PA
• AMD is a promising/convenient water source for
hydraulic fracturing


Thank You for
Your Attention

Questions?


Natural Gas Production

Source: Annual Energy Outlook, EIA, 2011


History of Hydrofracturing
• First test in 1903
• First commercial use in 1949
• More than 1,000,000 wells by 1998
• Nowadays, 35,000 wells per year with new
technology


Well Pad

Madden 2H, Lycoming County


Multiwell Pads


Rapid Marcellus Development


Typical Efficiencies of Thermoelectric
Power Plants

Source: Stilwell et al., 2009


Water Use in Thermoelectric Power Plants


Flow scheme 1: Conventional Water Management

Flowback
“Fresh” Class II Well
Water Disposal
Well 1

 Represents Maximum Water Demand
(No Water Reuse)
 Conventional approach in Barnett and other plays
 Difficult in Marcellus (only 7 Class II wells)


Flow scheme 2: On-Site Primary Treatment for Reuse

On-Site
Settling
SS & FR Rem
Well 1

High TDS
Reuse Water

Blend

Makeup Water
(Fresh Water)
Well 2


Flow scheme 3: Off-Site Primary Treatment for
Reuse

Sedimenta-
On-Site Rapid Mix tion & Hard- Rapid Sand
Settling w/ Caustic Filter
ness Rem
SS Removal & Flocculant

Well 1 Near-Field Disinfect
Belt Press
Primary (Ozone or
Treatment Peroxide)
Solids to Landfill

High TDS Water
For Reuse
Blend

Makeup Water
(Fresh Water)
Well 2


Flow scheme 4: Off-Site Primary Treatment and
Demineralization

Demineral- Concentrated
On-Site Near Field Ization Brine
Settling
SS Removal
Primary
Treatment Mechanical
Well 1
Vapor
Recomp Disposal
(Class II Well)
Or
By-Product
Recovery
Distilled Water (Crystallizer)
For Reuse
Blend
Makeup Water
(Fresh Water)
Well 2


Economic Comparison of Flow Schemes
Basis: 1 million gallons of flowback (23,800 barrels)
Flow Scheme FS 1 FS 2 FS 3 FS4
Method Transport to “In Field” Primary “Near Field” “In-Field”
Class II Well Treatment Precipitation Evaporation
for Disposal for Reuse for Reuse for Reuse

Treatment $ - 71 83 119
Transport $ 75 1 24 24
Brine Disposal $ 60 - - 19
Sludge Disposal $ - 2 6 6

Total Cost ($x1000) 135 74 113 168
Cost per barrel 5.67 3.10 4.75 7.05
Hardness Removal 100% 0% 97% 100%
Ba removal 100% 0% 99% 100%
Salt Removal 100% 0% 0% 100%
Water reused 0 99% 97% 90%

Geosteering


Resource Development
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Water Quality, Quantity, and Management: Lessons from the Marcellus Shale Region

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Water Quality, Quantity, and Management: Lessons from the Marcellus Shale Region

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