Evaluation of Produced Water Reuse for Hydraulic Fracturing In Eagle Ford

1. Evaluation of Produced Water Reuse for
Hydraulic Fracturing
In Eagle Ford
Atlantic Council Produced Water Workshop
June 24-25, 2013
Steve Jester, Sr. Principal Environmental Engineer
Lower 48 HSE, Houston, TX
Kevin Bjornen, Drilling and Completion Fluid Specialist,
Production Technology, Bartlesville, OK
Ramesh Sharma, Staff Process Engineer,
Process and Facility Engineering, Houston, TX

2. ConocoPhillips’ Corporate Water Sustainability Position:
As a responsible global energy company committed to sustainable
development, we recognize that fresh water is an essential natural
resource for communities, businesses, and ecosystems. Global
population growth will increase demand for fresh water and all
users – domestic, agriculture, and industry – will need to effectively
manage supplies to meet demands.
ConocoPhillips produces and utilizes water in its operations. We are
committed to the development of water management practices
that conserve and protect fresh water resources and enhance the
efficiency of water utilization at our facilities. We will assess,
measure, and monitor our fresh water usage and based on these
assessments we will manage our consumption and strive to reduce
the potential impact to the environment from wastewater disposal.

3. What is “Freshwater”
Texas Bureau of Economic Geology (BEG)
U.S. Geological Survey (USGS)

4. Fresh Water Utilization
BEG / API

5. Eagle Ford – 16 Counties in TX- Water Demand Comparison
2008 Water Use Survey Summary Estimates
Eagle Ford Counties
Livestock
4%
Drilling &
Completions
5.5-6.7%
Irrigation
64%
Steam Electric
5%
Mining
3%
Manufacturing
1%
Municipal
17%
540,000 Ac-Ft Total
347,000 ac-ft
29,700 -
36,000 ac-ft
Source: TX Water Development Board (http://www.twdb.state.tx.us/wrpi/wus/2008est/2008wus.asp)

6. Why Look at Produced Water Reuse? – Key Drivers
Part of an overall water management strategy
Implementing our company position- how can we use less
fresh water?
Optimize our process
Alternative Sources:
 Brackish/saline water
 Municipal wastewater
 Produced water?
 Where other water sources are scarce or expensive
 Where ample volumes of PW are available and easy to treat
and transport for reuse
Alternative process?

7. Challenges Using Alternative Water Sources for Hydraulic Fracturing
Transportation and gathering of water (logistics/traffic/envir.)
Treatment of water (cost/lifecycle environmental impact)
Storage of nonfresh water (bacteria/corrosion/environmental)
Blending of water from different sources (produced/fresh)
Consistent and predictable fracturing fluid
performance (pre-testing & consistent stream)
Impacts on reservoir and fracture conductivity (rock-fluid
interaction & pack damage)
Impacts on short & long term field production (emulsion,
scaling, corrosion)
Consistent and predictable fracturing fluid
performance

8. When Does Using Challenged Water Sources Make Sense?
Drivers for Produced or Alternative
Water Source
High Low
High quality source
water availability
Produced Water
Quality & Availability
Low High
Transportation &
Logistics
Adds cost Reduces cost
Compatibility w/ frac
chemistry
Low High
Compatibility w/
reservoir
HighLow
SWEET SPOT
Landowner Agreements, Regulatory Considerations

9. Produced Water Quality
Variability is the key term
 Individual well
 Well to well
 Field to field
 Region to region
Produced water typically has a much higher
 Total Dissolved Solids (TDS)
 Suspended Solids
 Iron
 Hardness/Scaling potential
 Boron
 Oil residue and organic matter

10. pH
Ferric iron (Fe+3)
Ferrous iron (Fe+2)
Total hardness
Magnesium (Mg+2)
Calcium (Ca+2)
Specific gravity
Chlorides (Cl-)
Carbonate (CO3-2)
Bicarbonate (HCO-3)
Sulfate (SO4-2)
Phosphate (PO4-3)
Silica (SI+4)
Boron (B+3)
Total dissolved solids (TDS)
Total suspended solids (TSS)
Bacteria
Water Quality Impacts on Fracturing Fluids
Total Fe >25 ppm
Impacts hydration and
thermal stability of polymer.
Dilute or dump.
Cl- New CMC systems are intolerant
Interferes with buffers in crosslink
systems. Some friction reducers are
prone to precipitation.
SO4
-2 >200 ppm Interferes with delayed
metallic crosslinkers. High temperature
thermal stability also impacted.
Precipitate out.
HCO3
-1 >600 ppm
Requires pH adjustment for
polymer hydration. Impacts
Zr crosslinkers (delay
and/or stability)
SI-4 Interferes metallic crosslinkers.
PO4
-3 ties of metallic
crosslinkers. Reduces fluid
performance.
Too High > 9.0 poor
hydration.
Too Low < 6.0 poor
dispersion.
Degradation of Organic Polymers
Even after the bacteria have been killed
their enzymes are still problematic
B >4 ppm can cause
crosslinking in guar gelling
agents.
Typical ionic species identified and quantified
in source water analysis.
Nearly every produced water
will push these limits

11. Initiatives At ConocoPhillips – Where can we reuse Produced Water?
West Texas
 Produced water primarily
 Modest water treatment
 Low temperature reservoirs (<200 F)
 Use of large portable storage tanks
 Feasible w/ scarcity of fresh water in region
Bakken
 Challenging brine (High TDS and scaling species)
 Blending with fresh water investigated
 Challenges with high performance fracturing fluids (>225 F)
 High temperature reservoir
 Scaling potential in water
Eagle Ford
 Produced water volumes are low (20-30 bbl/day/well)
 Blending with fresh water investigated
 Challenges with high performance fracturing fluids (>270 F)
 High temperature reservoir
 Scaling potential in water

12. Fluid Package Compatibility w/ Produced Water
Slick water and linear gels
 Salt and hardness tolerant polymers are readily available
 Possible pH adjustment for hydration
 Verify compatibility from polymer identification and testing
Guar borate systems
 Generally adaptable to a variety of water conditions
 Desirable characteristics (early viscosity, shear recovery) proppant placement
 Requires high pH (8.5 to +12)
 Low temperature (8.5 – 10.0)
 High temperatures requires higher pH (10 – 12+)
 Limited performance above 300 F
Metallic crosslink system
 More potential issues with challenging waters
 Flexible pH (4 – 11)
 Must be properly delayed (shear degrading)
 Balancing delay and early crosslinking/viscosity is difficult
Completion service industry
 Existing crosslinked packages developed for fresh water
 Adapting fluids to more challenging conditions
 Need to develop packages specifically for challenged water

13. ConocoPhillips High Performance Fracturing Fluid Requirements
Temperature testing (seasonally adjusted)
 Hydration (70 – 80 F)
 Wellbore transport (worst case no heat added)
 Fast temperature ramp (10 – 20 minutes to BHST)
 Stability for duration of pump time (practical limits)
Shear testing
 Rheometer geometry (R1B5 or R1B5X)
 Shear History (representative shear for residence time)
 Fracture Shear (100 s-1)
Ideal viscosity
 Slightly building apparent viscosity during high shear period
 ~100 cp apparent viscosity when entering 100 s-1 period
 Quick ramp to viscosity peak without thermal thinning period
 >200 cp apparent viscosity for duration of pump time
Ideal Viscosity Response
(High Performance Fluid)
0
200
400
600
800
1000
0:00 0:30 1:00 1:30 2:00
Time (HH:MM)
ApparentViscosity(cp)andShear
Rate(1/s)
50
100
150
200
250
300
Temperature(degF)
Shear Rate
Apparent Viscosity
Fluid Temperature
High Shear
Period
Early Time
Viscosity
(Wellbore)
Thermal
Stability for
Pump Time
Ideal Viscosity Response
(High Performance Fluid)
0
200
400
600
800
1000
0:00 0:30 1:00 1:30 2:00
Time (HH:MM)
ApparentViscosity(cp)andShear
Rate(1/s)
50
100
150
200
250
300
Temperature(degF)
Shear Rate
Apparent Viscosity
Fluid Temperature
High Shear
Period
Early Time
Viscosity
(Wellbore)
Thermal
Stability for
Pump Time
Ideal Viscosity Response
(High Performance Fluid)
0
100
200
300
400
500
0:00 0:06 0:12 0:18 0:24 0:30
Time (HH:MM)
ApparentViscosity(cp)andShear
Rate(1/s)
50
100
150
200
250
300
Temperature(degF)
Shear Rate
Apparent Viscosity
Fluid Temperature
Slight
Viscosity
Build During
High Shear
100 cp Coming Out of
High Shear and No
Thermal Thinning
Ideal Viscosity Response
(High Performance Fluid)
0
200
400
600
800
1000
0:00 0:30 1:00 1:30 2:00
Time (HH:MM)
ApparentViscosity(cp)andShear
Rate(1/s)
50
100
150
200
250
300
Temperature(degF)
Shear Rate
Apparent Viscosity
Fluid Temperature
Thermal
Stability for
Pump Time

14. Eagle Ford Produced Water - Fracturing Fluid Testing
Borate systems employed: Adaptable systems
Service Companies adapted formulations
 Similar performance
 Some cost Increase possible
Challenges for fluids
 Naturally occurring boron in water (require low pH during gel hydration, early crosslinking)
 High temperature challenge +270 F (requires high pH for borates)
 Enough hardness in water – immediate precipitation possible
 CaCO3
 Mg(OH)2
Viscosity Profiles with 70:30 Source:Produced Water Mix
0
200
400
600
800
1000
0:00 0:30 1:00 1:30 2:00
Time (HH:MM)
ApparentViscosity(cp),ShearRate(s-1)
50
110
170
230
290
350
Temperature(degF)
Viscosity - 70:30 Mix
Shear Rate - 70-30 Mix
Temp
Thermal
Stability for
Pump Time
Early Viscosity &
Some Thermal
Thinning

15. Challenges with High pH Guar Borate Systems – Eagle Ford
High pH to achieve borate cross-linking
drives CaCO3, and Mg(OH)2 scale formation
 No blending
 7000 lb solids with P95 fresh water
 3000 lb solids with P50 fresh water
 90/10 Fresh Water/Produced Water blend
 9800 lb solids P95 fresh water case
 4900 lb solids P50 fresh water case
250,000 lb of proppant used per stage
Impact of calcite solids and other scaling solids on proppant conductivity not
well understood
 Do the these solids flow back due to small micron size?
Calcite solids

16. Six Inch Pipe – 6 months of operation

17. Well Prep Frac Operation Plug Mill Out
Tubing
Installation
Well
TestingProduction
~80-90 K bbls of water per job
Typical Completion Activities – Eagle Ford
95% + water use
Other 5% of water used currently matches
produced water volumes where fluids
would typically be Slickwater and Linear
Gel systems employed in routine well work.
Produced water a realistic option here.

18. Our Approach: Minimal Treatment. Blend PW with Source Water
Goal: TSS and Oil and grease reduction
< 1/bbl treatment cost
Easy operation, smaller foot-print, mobile units
available (15 bbl/minute)
Polishing filter
TSS < 20 mg/L
pH = 7.5-8.0
TSS ~ 100 mg/L
pH = 7.5-8.0

19. Summary of Eagle Ford PW Reuse Challenges
Small % well work can be done with filtered produced water
Blending (90/10) source water/produced water for hydraulic
fracturing fluid preparation is possible
 Pre-mature cross linking of high boron content is an issue
 Higher concentration blends possible where slick water is used
 Consistent water quality is important
Immediate scaling is an issue with typical source waters with
borate systems and is magnified with produced water blends.
 Significant small fines will be pumped into fracture system
 Potential negative impact on fracture conductivity?
 Also true in other high temperature plays where pH needs to by high
(+10)
Need to develop frac packages specifically for challenged waters
Issues around flow assurance, logistics, and sub-surface rock-
water interactions need to be resolved for challenged water
sources

20. Conclusions
Produced Water Reuse is One Option – Subset of Overall Water
Management Strategy
 Optimize Process – 45% reduction
 Alternative Source – Brackish water 60%
 PW Reuse - challenging
Reuse of Produced Water – Depends on complex evaluation of
Compatibility, Logistics, Reliability, Cost, Environmental
Considerations
Reducing Freshwater Use has been better accomplished via
other alternatives
No Single industry-wide “Fit for Purpose” Solution

21. Questions?

22. Backup Slides

23. Water Quality Data Gathering
Well Produced water
Saline water
(Carrizo)
Fresh Water
(Gulf Coast)
Calcium, mg/L 690-2600 10 90.7 (42.2)
Magnesium, mg/L 54-210 Not available 17.7 (10.8)
Boron, mg/L 54-130 < 1 < 1
TDS, mg/L 17000-36000 1200-1600 1722 (763)
Bicarbonate, mg/L 330-1400 720-950 480 (252)
Iron, mg/L 4-98 <8 <8
Sulfate, mg/L 18-160 30 385 (157)
• PW sampling in Jan/Feb 2012
• Carrizo data is based on limited sampling
• 95th percentile (median) values shown for fresh water

24. Impact of Water Quality: Scaling Tendency
SI >0 means precipitation can happen
SI >2.5 scale inhibitor dosage increases significantly
SI>3 scale inhibitor will not be effective
All water sources are saturated with respect to calcite
0
0.5
1
1.5
2
2.5
3
3.5
100% Carrizo 100% Fresh water
P95
100% Fresh water
P50
100% PW P75
CalciteSaturationIndex
0
100
200
300
400
500
600
700
800
Calciteconcentration,mg/L
Surface PT
Bottom-hole PT
concentration, mg/L