Recycling Flowback and 

Produced Water for Use With 

Cross-linked Gel Fracs: 

Challenges and Solutions 

October 29th, 2014 

Noble Energy Inc. – Adam Prior, P.E. 

 Colorado State University – Ken Carlson 
Forward-looking Statements and 

Non-GAAP Measures 

This presentation contains certain “forward-looking statements” within the meaning of the federal securities law. Words such as “anticipates,” 

“believes,” “expects,” “intends,” “will,” “should,” “may,” and similar expressions may be used to identify forward-looking statements. Forwardlooking statements are not statements of historical fact and reflect Noble Energy’s current views about future events. They include estimates of oil 

and natural gas reserves and resources, estimates of future production, assumptions regarding future oil and natural gas pricing, planned drilling 

activity, future results of operations, projected cash flow and liquidity, business strategy and other plans and objectives for future operations. No 

assurances can be given that the forward-looking statements contained in this presentation will occur as projected, and actual results may differ 

materially from those projected. Forward-looking statements are based on current expectations, estimates and assumptions that involve a number 

of risks and uncertainties that could cause actual results to differ materially from those projected. These risks include, without limitation, the 

volatility in commodity prices for crude oil and natural gas, the presence or recoverability of estimated reserves, the ability to replace reserves, 

environmental risks, drilling and operating risks, exploration and development risks, competition, government regulation or other actions, the ability 

of management to execute its plans to meet its goals and other risks inherent in Noble Energy’s business that are discussed in its most recent 

Form 10-K and in other reports on file with the Securities and Exchange Commission. These reports are also available from Noble Energy’s offices 

or website, http://www.nobleenergyinc.com. Forward-looking statements are based on the estimates and opinions of management at the time the 

statements are made. Noble Energy does not assume any obligation to update forward-looking statements should circumstances or 

management's estimates or opinions change. 

This presentation also contains certain historical and forward-looking non-GAAP measures of financial performance that management believes are 

good tools for internal use and the investment community in evaluating Noble Energy’s overall financial performance. These non-GAAP measures 

are broadly used to value and compare companies in the crude oil and natural gas industry. Please also see Noble Energy’s website at 

http://www.nobleenergyinc.com under “Investors” for reconciliations of the differences between any historical non-GAAP measures used in this 

presentation and the most directly comparable GAAP financial measures. The GAAP measures most comparable to the forward-looking nonGAAP financial measures are not accessible on a forward-looking basis and reconciling information is not available without unreasonable effort. 

The Securities and Exchange Commission requires oil and gas companies, in their filings with the SEC, to disclose proved reserves that a 

company has demonstrated by actual production or conclusive formation tests to be economically and legally producible under existing economic 

and operating conditions. The SEC permits the optional disclosure of probable and possible reserves, however, we have not disclosed our 

probable and possible reserves in our filings with the SEC. We use certain terms in this presentation, such as “net risked resources” and “gross 

mean resources.” These estimates are by their nature more speculative than estimates of proved, probable and possible reserves and accordingly 

are subject to substantially greater risk of being actually realized. The SEC guidelines strictly prohibit us from including these estimates in filings 

with the SEC. Investors are urged to consider closely the disclosures and risk factors in our most recent Form 10-K and in other reports on file with 

the SEC, available from Noble Energy’s offices or website, http://www.nobleenergyinc.com. 

2 
PRESENTATION SUMMARY 

! Background of Noble operations 

! Understanding the fluids alternatives 

! Water systems optimization 

! Flowback and produced water quality 

! Treatment challenges 

! Case studies 

! Conclusions 

3 
Noble DJ BASIN OPERATIONS 

4 

! 2014 Development 

! Target 320 wells spud 

! Expanding into Northern 

Colorado 

! Best economics with 85% liquids 

! 2015 Growth 

! Target 327 wells spud 

! 600 Standard length equivalent 

wells 
 NIOBRARA 

! Noble Energy well development and operations will produced 9 

million bbls of flowback and produced water in 2014 

! This is an opportunity to reduce reliance on fresh water 

Procure 

Fresh 

Water 

Truck 

Fresh 

Water 

Frack

Truck 

Wastewater 

Dispose 

Wastewater 

Procure 

Fresh 

Water 

Pipe 

Fresh 

Water 

Frack

Pipe 

Wastewater 

Recycle Frack

Reuse 

5 
WQFrac 

Water Systems Optimization 

Noble Energy/Colorado State University Modeling 

Fresh Source 

Water 

Flowback volume (VFB) 

Flowback water quality 

(WQFB) 

VFB 

WQFB 

Drilling/ 

Fracturing 

Injection 

Disposal well

Flowback

Water 

Treatment

VFrac 

WQFrac 

Frac Volume (VFrac) 

Previous water management strategy Current water reuse strategy 

Objective is to understand 

water quality limits of frac 

fluid 
WHY A NEED FOR RANGE OF FLUID SYSTEMS 

! Fluids 

! Different formations 

" Base on lithology 

" Additional mineral 

compounds 

! Different formation fluids 

! Different objectives 

! Different pumping 

configurations 

! Composition of gas or oil 

! Etc. 

7 
CROSSLINKED FRACS IN NIOBRARA 

! Different lithology 

! More conducive to Niobrara sandstone geology (more production) NIOBRARA MARCELLUS 

8 
COMMON FLUID SYSTEMS 

! Slickwater – Water with friction reducer 

! Minimal width, rate is used to carry proppant (smaller proppant) 

! Low viscosity of 2 – 3 cP

! Frack rate up to 100 bbl/min 

! Less impact to “tight” or impermeable formations 

! Can be more economical 

! Linear gel – Water with polymer/guar 

! Some frack width, some carrying capacity 

! Medium viscosity of 10 – 30 cP

! Frack rate from 60 to 100 bbl/min 

9 
COMMON FLUID SYSTEMS 

! Cross-linked gel – Water with polymer/guar & cross-linkers 

! High viscosity of 100 to 4000 cP

! Good frack width and proppant transport 

! Proppant does not settle as it enters formation 

! Less required HP → smaller locations 

! Rate up to 60 bbl/min 

! Higher initial costs 

! Less leak off of fluid into formation 

10 
Basics of Hydraulic Fracturing 

2014 Recycled Usage 

! YTD – 1,110,032 bbls

! Estimated – 1,500,000 bbls

2015 Projected Recycled Usage 

! Estimated – 3,500,000 bbls

NOBLE FRAC RECYCLING 
MORE THAN WATER TREATMENT 

! Difficult for water treatment companies to succeed in creating 

water that could be cross-linked alone 

! Leads to over treatment and/or economically unfeasible 

! Iterative cycle of improvement with water treatment technologies 

and with frac fluid formula 

12 
RECYCLING CHALLENGES OF X-LINKED FRACS 

! Water quality for cross-linked gel fracs is restrictive 

! Heavy metals interfere with cross-linking 

! Gels can be sensitive to TDS and hardness 

! Much more stringent that slickwater quality requirements 

! Some flowback characteristics are tough to treat 

! Unbroken gels overwhelm treatment processes 

! Emulsified oil or residual demulsifiers disrupt treatment processes 

! Varying water quality and types of water 

! Organics in the water 

13 
! WQ can vary 

significantly 

! Need to look at 

economics of WQ with 

fluids ! Increasing gel loading can 

add significant costs 

! May require additional 

additives 

! Example of fluid A and 

fluid B with same 

additives 

! Rheology testing a 

collaboration with 

Halliburton and CSU 

14 

CROSS-LINKED FRAC 

Water Quality 
! Flowback Water 

! Highly variable 

! WQ changes over time 

! Can have significant gels 

! Significant solids 

! Could be emulsion breakers 

! High organics 

! Produced Water 

! Formation characteristics 

" Chlorides 

" Sodium 

" Hardness 

" Metals 

! Potential for oil in water 

! High organics 

15 

WHAT’S IN THE WATER 

Flowback vs. Produced 
FLOWBACK WATER QUALITY 

16 

Total Organic Carbon (TOC) is the key parameter influencing treatment 

Well B - Hybrid 

Well D - Slickwater

Well G - Gel 
FLOWBACK WATER QUALITY 

17 

0 

500 

1,000 

1,500 

2,000 

2,500 

3,000 

3,500 

4,000 

4,500 

5,000 

0 10 20 30 40 50 60 

DOC (mg/L) 

Time (days) 

0 

500 

1,000 

1,500 

2,000 

2,500 

3,000 

3,500 

4,000 

4,500 

0 20 40 60 

Total Carbohydrates 

mg/L Glucose 

Time (Days) 

0% 

5% 

10% 

15% 

20% 

25% 

30% 

35% 

40% 

45% 

50% 

0 10 20 30 40 50 60 

% of TOC as 

Glucose 

Time (days) 

! Total and dissolved organic 

Carbon is high 

! Carbohydrates comprise much 

of Early Time Flowback organic 

load 

! Fraction of OM that is gel related 

decreases rapidly 
COLLOID RESTABILIZATION 
INFLUENCE OF TDS 

19 

Ionic strength (TDS) increases with well age reducing electric double 

layer thickness (enhancing collisions and coagulation) 

0.0 

1.0 

2.0 

3.0 

4.0 

5.0 

6.0 

7.0 

8.0 

11,376 10,966 23,114 17,368 28,815 25,457 36,969 38,171 34,356 

EDL thickness, 

Å

TDS, mg/L 

0.0 

1.0 

2.0 

3.0 

4.0 

5.0 

6.0 

7.0 

8.0 

0 5000 10000 15000 20000 25000 30000 35000 40000 45000 

EDL thickness, 

Å

TDS, mg/L 
CASE STUDY I – CONCORD PRODUCED WATER SERVICES 

High capacity coalescing 

separator 

Kinetic oxidation 

Cavitation sterilizer 

Dissolved air flotation (DAF) 

Micro bubble curtain filter 

Sludge dewatering 
CASE STUDY I – CONCORD PRODUCED WATER SERVICES 

21 
CASE STUDY I - Economical Recycle Model 

On-site capture of coil 

tubing, flowback and 

produced water 

Understand desired 

water quality parameters 

Transfer recycled water 

via pipeline where 

feasible 

Maximize recycle 

volume 

Recover oil onsite for 

resale by producer 

Proper solids handling 

22 

Keys to Economical 

Recycling 

Influent Water Quality

pH Fe Al Ca Mg SO4 Alk Turbidiy TSS

7.9 26 0.76 212 91.8 357 632 105 484

Effluent Water Quality

pH Fe Al Ca Mg SO4 Alk Turbidity TSS

6.9 0.742 0.034 168 90.6 12.1 255 6 7
! Develop a solution to treat early time flowback and coil tubing 

water in the DJ Basin 

! Tune treatment process to meet necessary fracturing fluid water 

quality without over treating 

Raw! Treated!

pH! 6.52! 7.00!

Specific!Gravity! 1.012! 1.013!

Chlorides!(mg/L):! 11400! 11000!

Potassium!(mg/L):! 400! 400!

Sodium!(mg/L):! 7130! 6851!

Sulfate!(mg/L):! 1700! 18!

Iron!(mg/L):! 74! 2!

Carbonates!(mg/L)! 0! 0!

Bicarbonates!(mg/L)! 813! 325!

Calcium!(Ca)!(mg/L):! 122! 88!

Magnesium!(Mg)!(mg/L):! 46! 24!

Total!Dissolved!Solids!(mg/L)! 21686! 18709!

Turbidty!(NTU)! 800+! 6!

CASE STUDY II – HALLIBURTON WATER SOLUTIONS 
CASE STUDY II – HALLIBURTON WATER SOLUTIONS 

24 

Produced(Waer Day(3(Flowback Coil(Water

Hydrochloric(Acid 17 14 14

Sodium(Hydroxide 35 87 156

Ferric(Chloride 67 163 336
CASE STUDY II – HALLIBURTON WATER SOLUTIONS 

25 

Closing the Loop : Rheology testing of recycled fluid 

Flowback volume (VFB) Frac Volume (VFrac) 

WQFrac 

Fresh source 

water 

Flowback water quality 

(WQFB) 

VFB 

WQFB 

Drilling/ 

fracturing 

Injection 

disposal well

Flowback 

water 

treatment

VFrac 

WQFrac 

Objective is to understand 

water quality limits of frac 

fluid 
WATER TREATMENT, RECYCLING & REUSE 

!Fixed facility 

!Most economical 

" Fixed power costs 

" More consistent water quality 

" Optimized chemical application 

!More consistent effluent water quality 

!Possible negatives 

!May have to truck water 

!Proper sizing can be issue 

Economics 

Field-Scale 

Success 

Meets water quality 

requirements in bench 

scale 

26 
WATER TREATMENT, RECYCLING AND REUSE 

!Mobile Recycling 

!Can be near frac operations 

!Potential for piping fluids 

!Possible negatives 

!Higher costs 

!May have inconsistent water 

quality and quantity 

" Potentially impacts on frac

!System must be designed for 

all water qualities 

27 

Economics 

Field-Scale 

Success 

Meets water quality 

requirements in bench 

scale 
CONCLUSIONS 

! Recycling gel and slickwater frack flowback is feasible and CAN 

be economical for use in cross-linked fracs

! Process required a progressive and iterative approach 

! Bench Scale → Pilot Scale → Full Scale 

! Treatment processes → Based on what’s in the water 

! Frac fluid → Understand TRUE sensitivity of frac fluid to water quality 

! Treatment processes → Flexible based on WQ and fluid requirements 

! Proper recycling has no adverse impacts to fracs or production 

! Potentially modify frac fluid to be less sensitive to recycled WQ 

28 
GOAL IS TO CONTINUE TO 

INCREASE RECYCLED WATER USE 

WITH GEL FRACS