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SPE DISTINGUISHED LECTURER SERIES is funded principally through a - - PowerPoint PPT Presentation

SPE DISTINGUISHED LECTURER SERIES is funded principally through a grant of the SPE FOUNDATION The Society gratefully acknowledges those companies that support the program by allowing their professionals to participate as Lecturers. And


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SLIDE 1

SPE DISTINGUISHED LECTURER SERIES

is funded principally through a grant of the

SPE FOUNDATION

The Society gratefully acknowledges those companies that support the program by allowing their professionals to participate as Lecturers. And special thanks to The American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) for their contribution to the program.

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SLIDE 2

Application of Low Viscosity Application of Low Viscosity Fracturing Fluids Fracturing Fluids-

  • Water

Water Frac’s Frac’s

Presented By: Larry K. Britt Presented By: Larry K. Britt NSI Technologies, Inc. NSI Technologies, Inc. 918 918-

  • 496

496-

  • 2071

2071

slide-3
SLIDE 3
  • History of Water

History of Water Frac’s Frac’s

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water As A Fracturing Fluid: What We Know Or Think We Know?

slide-4
SLIDE 4

Water Frac History Water Frac History

The History Of Water Fracs Is As Long As The History Of Fracturing Itself!

slide-5
SLIDE 5

Water Frac History Water Frac History

The History Of Water Fracs Is Both Long And Interesting!

slide-6
SLIDE 6

1988 Paper On The Hugoton Field

Water Frac History Water Frac History

Water Water Fracs Fracs In Hugoton Not Better Or Cheaper? In Hugoton Not Better Or Cheaper?

Nitrogen Foam 100 M-Gal 60Q foam pumped at 75 bpm Pad Volume was 36% of the Total Job 12/20 Sand Proppant pumped at 1 to 5 PPG Slick Water 140 M-Gal 20# Slick Water pumped at 100 bpm Pad Volume was 23% of the Total Job 12/20 Sand Proppant pumped at 0.5 to 2.5 PPG Borate X-Link Gel (30# HPG) 100 M-Gal 30 ppt HPG, borate X-Link gel at 60 bpm Pad Volume was 35% of the Total Job 12/20 Sand Proppant pumped at 1 to 5 PPG

N2 TW XL N2 TW XL

slide-7
SLIDE 7

SPE 49104 “Water Frac Results From 50 Cotton Valley Wells”

Water Frac History Water Frac History

Water Water Fracs Fracs Lower IP Shallower Decline Than Gel! Lower IP Shallower Decline Than Gel!

No Better Than Gel Fracs

100 200 300 400 500 500 1,000 1,500

TIME (days)

Water Frac 82,000 lb X-Link Frac 1,100,000 lb X-Link Frac 520,000 lb

MCFPD

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10 20 30 50 100 200 300 500 1,000

Cumulative Frequency

Water Fracs Gel Fracs

6-Month Cum, MMCF

slide-8
SLIDE 8

SPE 60285 “Comprehensive Evaluation Of Fractured Gas Wells Utilizing Production Data”

Water Frac History Water Frac History

Water Water Fracs Fracs In ETCV Not Better, Cheaper? In ETCV Not Better, Cheaper?

100 200 300 400 500 600

Area 1

Gel Fracs

Area 4 Area 3 Area 2 Area 6 Area 5 Area 7 Area 8

"Normalized" Production Data Water Fracs

MCFPD

slide-9
SLIDE 9

Water Frac History

Cost Reduction Results From Material Scheduling And Alliance Contracts!

Water Water Fracs Fracs In ETCV Cheaper? In ETCV Cheaper?

A Review Of Gel And Water Fracs:

Parameter Description Cross -linked Gel Fracs Treated Water

  • Fracs

Average Pump Rate, BPM 29.0 25 Average Pad Fraction, % 34.9 41.5 Average ISIP, psi 2844 2604 Average Sand Pumped, mlbs 526.6 71.0

  • Max. Sand Concentration, ppg

6.3 2.3 Average Treating Pressure, psi 2286 4245 Number of Stimulation Stages 3.3 3.5

slide-10
SLIDE 10

Water Frac History Water Frac History

Always Been Used In Naturally Fissured Reservoirs! Always Been Used In Naturally Fissured Reservoirs!

150 300 450 600

  • 450
  • 300
  • 150

150 300

West-East (ft) North (ft)

MWX-3 MWX2 MONITOR N74W AT INTERSECTION HORIZONTAL WELL

150 300 450 600

  • 450
  • 300
  • 150

150 300

West-East (ft) North (ft)

MWX-3 MWX2 MONITOR N74W AT INTERSECTION HORIZONTAL WELL

Multi-Well Site Mesaverde Formation

slide-11
SLIDE 11

Water Frac History Water Frac History

Summary: Summary:

  • Long History Of Application

Long History Of Application

  • Lower IP, Shallower Production Decline?

Lower IP, Shallower Production Decline?

  • Gels Generally As Good Or Better?

Gels Generally As Good Or Better?

  • Water

Water Fracs Fracs Cheaper Cheaper -

  • “More Economic?”

“More Economic?”

  • Good For

Good For Some Some Fissured Reservoirs! Fissured Reservoirs!

slide-12
SLIDE 12
  • History of Water

History of Water Fracs Fracs

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water As A Fracturing Fluid: What We Know Or Think We Know?

slide-13
SLIDE 13

Water as a Fracturing Fluid Water as a Fracturing Fluid Multiple, Conflicting Desires Multiple, Conflicting Desires

  • Breaking

Breaking

  • Cheap

Cheap

  • Cleanliness

Cleanliness

  • Compatibility

Compatibility

  • Formation

Formation

  • Formation Fluid

Formation Fluid

  • Reservoir Pressure

Reservoir Pressure

  • Easy to Mix

Easy to Mix

  • Additive Sensitivity

Additive Sensitivity

  • Environmentally

Environmentally

  • Fluid Loss

Fluid Loss

  • Low Pump Pressure

Low Pump Pressure

  • Safety

Safety

  • Viscosity ???

Viscosity ???

  • Poor Proppant Transport

Poor Proppant Transport

  • Height Containment

Height Containment

  • Poor Fracture Width

Poor Fracture Width

√ √ √ √ √ √ X X X/√/X

slide-14
SLIDE 14

Water As A Fracturing Fluid Water As A Fracturing Fluid

It’s Clean It’s Clean

slide-15
SLIDE 15
  • Residual Material in Fracture

Residual Material in Fracture

  • Gel Residue

Gel Residue

  • Damaged Proppant

Damaged Proppant

  • Formation Fines

Formation Fines

  • Degradation of Proppant

Degradation of Proppant

  • Flow/Reservoir Considerations

Flow/Reservoir Considerations

  • Viscosity

Viscosity

  • Capillary Pressure

Capillary Pressure

  • Non

Non-

  • Darcy Flow

Darcy Flow

  • Multi

Multi-

  • Phase Flow

Phase Flow

  • Darcy versus Yield

Darcy versus Yield-

  • Power Law

Power Law

What Affects Proppant Pack Permeability? What Affects Proppant Pack Permeability?

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SLIDE 16

A 20% Porosity Reduction Results in a 60% Loss in Permeability!

  • Gel Residue

Gel Residue

  • Damaged Proppant

Damaged Proppant

  • Formation Fines

Formation Fines

  • Proppant Degradation

Proppant Degradation

The Effect of Residual Material in Fracture? The Effect of Residual Material in Fracture?

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SLIDE 17

Typical East Texas Fracture Stimulation: Typical East Texas Fracture Stimulation:

(527 (527 mlbs mlbs 20/40 Jordan Sand, 138 20/40 Jordan Sand, 138 mgals mgals of 30# /mgal Guar)

  • f 30# /mgal Guar)

Volume of Porosity Volume of Porosity = (527,000 lbs/22 lbs/gal) * (0.4/(1 = (527,000 lbs/22 lbs/gal) * (0.4/(1-

  • 0.4))

0.4)) = 15,970 gals = 15,970 gals Residual Polymer = 0.05 * 138,000 gals Residual Polymer = 0.05 * 138,000 gals = 6,900 gals = 6,900 gals Proppant Fines = 0.032 * (527,000 lbs/22 lbs/gal) = Proppant Fines = 0.032 * (527,000 lbs/22 lbs/gal) = 766 gals 766 gals Formation Fines = 0.0 Formation Fines = 0.0 = = 0 gals 0 gals Proppant Degradation = 0.0 Proppant Degradation = 0.0 = = 0 gals 0 gals Damage Volume = Damage Volume = 7,666 gals 7,666 gals

Fractional Reduction in Porosity= 0.48 Fractional Reduction in Porosity= 0.48

Why Does it Matter? Why Does it Matter?

slide-18
SLIDE 18

Why Does it Matter? Why Does it Matter?

Because we are Paying for Length and Conductivity! Because we are Paying for Length and Conductivity!

A 48% Porosity Reduction Results in a 90% Loss in Permeability!

  • Reduced

Reduced k kf

fw

w Increases $$! Increases $$!

  • Reduced

Reduced k kf

fw

w Reduces Reduces x xf

f !

!

  • F

FCD

CD= 2 Optimum (

= 2 Optimum (Prats Prats) )

  • k

kf

fw

w Impact on Effective Impact on Effective x xf

f

slide-19
SLIDE 19

What Affects Proppant Pack Permeability? What Affects Proppant Pack Permeability?

  • Residual Material in Fracture

Residual Material in Fracture

  • Gel Residue

Gel Residue

  • Damaged Proppant

Damaged Proppant

  • Temperature Degradation of Proppant

Temperature Degradation of Proppant

  • Formation Fines

Formation Fines

  • Flow/Reservoir Considerations

Flow/Reservoir Considerations

  • Viscosity

Viscosity

  • Capillary Pressure

Capillary Pressure

  • Non

Non-

  • Darcy Flow

Darcy Flow

  • Multi

Multi-

  • Phase Flow

Phase Flow

  • Darcy versus Yield

Darcy versus Yield-

  • Power Law

Power Law

slide-20
SLIDE 20

The Effect of Flow/ Reservoir Considerations? The Effect of Flow/ Reservoir Considerations?

  • Viscosity

Viscosity

  • Capillary Pressure

Capillary Pressure

  • Non

Non-

  • Darcy Flow

Darcy Flow

  • Multi

Multi-

  • Phase Flow

Phase Flow

  • Darcy versus Yield Power Law

Darcy versus Yield Power Law

Damage Mechanism Damage Mechanism

slide-21
SLIDE 21

The Effect of Flow Reservoir Considerations? The Effect of Flow Reservoir Considerations?

  • Viscosity

Viscosity

  • Capillary Pressure

Capillary Pressure

  • Non

Non-

  • Darcy Flow

Darcy Flow

  • Multi

Multi-

  • Phase Flow

Phase Flow

  • Darcy vs. Yield Power Law

Darcy vs. Yield Power Law

Damage Mechanism Damage Mechanism

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SLIDE 22

The Effect of Flow Reservoir Considerations? The Effect of Flow Reservoir Considerations?

  • Viscosity

Viscosity

  • Capillary Pressure

Capillary Pressure

  • Non

Non-

  • Darcy Flow

Darcy Flow

  • Multi

Multi-

  • Phase Flow

Phase Flow

  • Darcy vs. Yield Power Law

Darcy vs. Yield Power Law

Damage Mechanism Damage Mechanism

0.01 0.1 1 10 100 1000 10000 100000 1000000 10000000 Cumulative Production (MCF) PI ratio (MCF/D/psi) Production spikes caused by changes in bottom hole pressure used to control well Gel Damage Multiphase Flow Effect Viscous Effects phi = 7.2% kg = .01 md h = 40 ft A = 160 acres pi = 5830 psi xf = 2500 ft kfw = 188 md-ft gel visc. = 9.56 cp

slide-23
SLIDE 23

The Effect of Flow/ Reservoir Considerations? The Effect of Flow/ Reservoir Considerations?

  • Viscosity

Viscosity

  • Capillary Pressure

Capillary Pressure

  • Non

Non-

  • Darcy Flow

Darcy Flow

  • Multi

Multi-

  • Phase Flow

Phase Flow

  • Darcy vs. Yield Power Law

Darcy vs. Yield Power Law Damage Mechanism Damage Mechanism

Yield Yield-

  • Power Law Supported By:

Power Law Supported By:

  • Anecdotal Field Data

Anecdotal Field Data

  • PTA in TFG Reservoirs

PTA in TFG Reservoirs

  • Limited Laboratory Data

Limited Laboratory Data

  • Simulation Studies

Simulation Studies

  • Actual Well Performance

Actual Well Performance

slide-24
SLIDE 24

The Effect of Flow Reservoir Considerations? The Effect of Flow Reservoir Considerations?

Laboratory Data Supports Yield Stress Concept Laboratory Data Supports Yield Stress Concept

slide-25
SLIDE 25

The Effect of Flow/ Reservoir Considerations? The Effect of Flow/ Reservoir Considerations?

Fracture Fluid Cleanup Fracture Fluid Cleanup

  • f an East Texas
  • f an East Texas

(Cotton Valley) Well (Cotton Valley) Well After 5 Years of Production After 5 Years of Production Darcy Cleanup Darcy Cleanup vs vs. . Yield Yield-

  • Power Law

Power Law

Darcy Flow Yield-Power Law Wellbore Fracture Tip @ 2500’

Microsoft

  • werPoint Presentatio
slide-26
SLIDE 26

The Effect of Flow Reservoir Considerations? The Effect of Flow Reservoir Considerations?

k kf

fw

w Critical to Fracture Cleanup for Yield Critical to Fracture Cleanup for Yield-

  • Power Law Flow!

Power Law Flow!

200 400 600 800 1,000 1,200 500 1,000 1,500 2,000 2,500 3,000 Fracture Conductivity, mdft Effective Fracture Half Length, ft

East Texas Fracture: East Texas Fracture:

  • Only 40% (1000’) of

Only 40% (1000’) of Fracture Length Fracture Length Cleaned Up! Cleaned Up!

  • FCD of 8

FCD of 8-

  • 10 Needed to

10 Needed to Cleanup Entire Cleanup Entire Fracture! Fracture!

Post Frac Buildups

slide-27
SLIDE 27

The Effect of Flow Reservoir Considerations? The Effect of Flow Reservoir Considerations?

Operational Effects: Operational Effects: Pressure and Permeability Pressure and Permeability Matters! Matters! Tight Formation Gas Wells Tight Formation Gas Wells May Benefit From May Benefit From Systematic Shut Systematic Shut-

  • ins!

ins!

slide-28
SLIDE 28

The Effect of Flow/ Reservoir Considerations? The Effect of Flow/ Reservoir Considerations?

Shut Shut-

  • ins Prior to Gas

ins Prior to Gas Breakthrough May Breakthrough May Improve Polymer Improve Polymer Recovery! Recovery!

slide-29
SLIDE 29

The Effect of Flow/ Reservoir Considerations? The Effect of Flow/ Reservoir Considerations?

Systematic Shut Systematic Shut-

  • ins Can Improve Gas Recovery!

ins Can Improve Gas Recovery!

slide-30
SLIDE 30

Productivity Polymer Returned

Polymer Recovery Polymer Recovery Results in Results in Improved Improved Productivity! Productivity!

The Effect of Flow/ Reservoir Considerations? The Effect of Flow/ Reservoir Considerations?

slide-31
SLIDE 31

To Achieve Our Fracturing Objectives ! To Achieve Our Fracturing Objectives !

  • Incorporate Cleanup Considerations in

Incorporate Cleanup Considerations in the Fracture Stimulation Design the Fracture Stimulation Design

  • Reduce/Eliminate Polymer

Reduce/Eliminate Polymer

  • Reduce/Eliminate Proppant Damage

Reduce/Eliminate Proppant Damage

  • Increase Fracture Conductivity

Increase Fracture Conductivity

  • Design For FCD >>10 In TFG Wells

Design For FCD >>10 In TFG Wells

  • Evaluate Operational Issues

Evaluate Operational Issues

  • Flow back

Flow back

  • Systematic Shut

Systematic Shut-

  • ins

ins

slide-32
SLIDE 32
  • History of Water

History of Water Fracs Fracs

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water As A Fracturing Fluid: What We Know Or Think We Know?

slide-33
SLIDE 33

What Is The Effect Of Poor Proppant Coverage!

Single Layer Evaluation of Water Frac Productivity 60% of Zone Stimulated kv/kh Ratio Varied

Assumes 0 Un-Propped kfw!

Water Frac Guidelines Water Frac Guidelines Effect Of Proppant Settling Effect Of Proppant Settling

20 % 100 % 80 % 60 % 40 % 20 % 100 % 80 % 60 % 40 %

slide-34
SLIDE 34 0.0001 0.0010 0.0100 0.1000 1.0000 10.0000 1 10 100 1000 10000 100000

Time, Days Productivity, MMCFPD

Full Vertical Frac 80% Vertical Frac, kv=0.01kh 60% Vertical Frac, kv=0.01kh 40% Vertical Frac, kv=0.01kh 20% Vertical Frac, kv=0.01kh 0.0001 0.0010 0.0100 0.1000 1.0000 10.0000 1 10 100 1000 10000 100000

Time, Days Productivity, MMCFPD

Full Vertical Frac 80% Vertical Frac, kv=0.01kh 60% Vertical Frac, kv=0.01kh 40% Vertical Frac, kv=0.01kh 20% Vertical Frac, kv=0.01kh 100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30 35 40 45 50

Time, Years Cumulative Gas, MMCF

Full Vertical Frac 80% Vertical Frac, kv=0.01kh 60% Vertical Frac, kv=0.01kh 40% Vertical Frac, kv=0.01kh 20% Vertical Frac, kv=0.01kh

Single Layer Evaluation of Water Frac Productivity

With Kv > 0 Limited Reserves Lost But Economics Impacted! Limited Proppant Coverage Results In Reduced IP And Shallower Decline!

Water Frac Guidelines Water Frac Guidelines Effect Of Proppant Settling Effect Of Proppant Settling

slide-35
SLIDE 35

Well Performance Characteristics Of Lower IP And Shallower Decline Are Emulated By

Vertical Reservoir Permeability, And Incomplete Proppant Coverage Of The Fracture!

What About A Residual Fracture Width? Water Frac Guidelines Effect Of Proppant Settling

slide-36
SLIDE 36

INLET Crack SEM EXIT FILTER FLUID COLLECTION Sand Core in Core Holder at Pressure

Sleeved Core Holder

Core Cracked with Masonry Splitter

Water Frac Guidelines Lab Tests Of Residual Fracture Width?

slide-37
SLIDE 37

2000 4000 6000 0.1 1 10 100 1,000

Effective Proppant Stress (psi)

Unpropped KfW Non-Aligned Cracks

Asperity Height Max Avg 0.26" 0.09" 0.19" 0.06"

A Residual kfw Of 1 mdft In The Un-Propped Fracture Is Likely In ETCV, However, It Depends:

  • 1. Mineralogy
  • 2. Stress State

Water Frac Guidelines Lab Tests Of Residual Fracture Width?

slide-38
SLIDE 38

What Is The Effect Of Poor Proppant Coverage!

Multiple Layer Evaluation of Water Frac Productivity 60% of Zone Stimulated kv/kh Ratio Varied

Assumes Un-Propped kfw!

Water Frac Guidelines Water Frac Guidelines Effect Of Proppant Settling Effect Of Proppant Settling

20 % 100 % 80 % 60 % 40 % 20 % 100 % 80 % 60 % 40 %

slide-39
SLIDE 39 100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30 35 40 45 50

Time, Years Cumulative Gas, MMCF

Full Vertical Frac 80% Vert Frac + 1 mdft 60% Vert Frac + 1 mdft 40% Vert Frac + 1 mdft 20% Vert Frac + 1 mdft

With Residual kfw In The Un-Propped Fracture No Reserves Are Lost!

Water Frac Guidelines The Effect Of Residual Fracture Width?

Lower IP Shallower Decline!

slide-40
SLIDE 40

Water Frac Guidelines Water Frac Guidelines Must Depend on Un Must Depend on Un-

  • Propped

Propped k kF

Fw

w

Hf Hp

KfW = ??

For “Downward” Flow

FCD-Vert > 2.0

Otherwise Productivity Lost!

Unpropped F Unpropped f Vert CD

H k w k F

− −

= ) (

Equivalent FCD

slide-41
SLIDE 41

Water Frac Guidelines Water Frac Guidelines Must Depend on Un Must Depend on Un-

  • Propped

Propped k kF

Fw

w

10 20 50 100 200 500 1000 2000 5000 0.2 0.3 0.5 1 2 3 5

Time (days) Rate (MCFD)

Cases with H-Prop = 20 to 100 ft All F = 3

Hf = 100' All = 5 k = 0.01 md Xf = 750' 80 Acres

CD

F

CD - Vert

As Long As FCD-Vert > 2 The Propped Fracture Height Doesn’t Matter! For (kfw)Un-propped = 1 mdft HF-Un-propped < 50 feet

Unpropped F Unpropped f Vert CD

H k w k F

− −

= ) (

slide-42
SLIDE 42

Water Frac Guidelines Water Frac Guidelines Must Depend on Un Must Depend on Un-

  • Propped

Propped k kf

fw

w

0.01 0.02 0.05 0.1 0.2 0.5 1 20 40 60 80

k (md) Max Unpropped H (ft)

KfW (UnPropped) 5 md-ft 1 md-ft 0.1 md-ft

Application: Low k, and Limited h!

slide-43
SLIDE 43
  • History of Water

History of Water Fracs Fracs

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water As A Fracturing Fluid: What We Know Or Think We Know?

slide-44
SLIDE 44

Water Frac Guidelines Water Frac Guidelines Reservoir: Reservoir:

  • Reservoir permeability should be

Reservoir permeability should be less than 0.1 md, less than 0.1 md,

  • k

kv

v/k

/kh

h > 0.0.

> 0.0.

slide-45
SLIDE 45

Water Frac Guidelines Horizontal Permeability Criteria:

1 10 100 1000 10000 100000 0.001 0.01 0.1 1 10 100

Perm eability, m d Fracture Conductivity, mdft F CD =10 F CD = 2

Upper Bound on W ater Frac k fw Low er Bound on W ater Frac k fw

k < 0.1 md

slide-46
SLIDE 46
  • History of Water

History of Water Fracs Fracs

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water As A Fracturing Fluid: What We Know Or Think We Know?

slide-47
SLIDE 47

Water Frac Guidelines Water Frac Guidelines Geomechanical Geomechanical: :

  • Some in

Some in-

  • situ stress to contain

situ stress to contain fracture geometry is required fracture geometry is required

  • Must have residual fracture width

Must have residual fracture width

  • Leak

Leak-

  • off should be less than 0.005
  • ff should be less than 0.005

ft/min ft/min1/2

1/2

slide-48
SLIDE 48

MUST MUST Have Height Confinement & Zonal Coverage?

Have Height Confinement & Zonal Coverage?

Water Frac Guidelines Must Address Geomechanical Issues!

Proppant Settling Below Pay! Proppant Settling Poor Perforation Coverage!

slide-49
SLIDE 49

Water Frac Guidelines Water Frac Guidelines Must Depend on Un Must Depend on Un-

  • Propped

Propped k kF

Fw

w

Hf Hp

KfW = ??

For “Downward” Flow

FCD-Vert > 2.0

Otherwise Productivity Lost!

Unpropped F Unpropped f Vert CD

H k w k F

− −

= ) (

Equivalent FCD

slide-50
SLIDE 50

0.01 0.03 0.1 0.3 1 3 0.002 0.003 0.005 0.01 0.02 0.03 0.05 0.07 0.09

k (md) 'C' (ft/√min)

Calculated Fluid Loss Coef.

k-rel = 0.5 , φ = 0.105 Ct = 200e-6 1/psi μ-gas = 0.02 cp

μ = 0.5 cp Δp = 3,000 psi No Filter Cake

filtrate

"Expected" Range

  • f "Allowable" Leak-Off

Water Frac Guidelines Water Frac Guidelines Geomechanical Geomechanical-

  • Fluid Loss

Fluid Loss

25 50 75 100 125 150 175 500 1,000 1,500 2,000 2,500 3,000

Volume (M-Gal) XF (ft)

30 bpm "Reasonable" H Confinement C = 0.001 C = 0.002 C = 0.005 0.01

Low Permeability! Reservoir Controlled Leak-Off Gel Leak-Off = Water Leak-Off !

slide-51
SLIDE 51
  • History of Water

History of Water Fracs Fracs

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water As A Fracturing Fluid: What We Know Or Think We Know?

slide-52
SLIDE 52

Water Frac Guidelines Water Frac Guidelines Operational/ Design Operational/ Design Water Water-

  • Frac Design:

Frac Design:

  • Un

Un-

  • propped (hydraulically created) fracture

propped (hydraulically created) fracture conductivity must be greater than 0.1 mdft ( conductivity must be greater than 0.1 mdft (F

FCD

CD-

  • Vert

Vert > 2

> 2),

),

  • Pump Rate required to provide fracture width three

Pump Rate required to provide fracture width three times the proppant diameter without violating fracture times the proppant diameter without violating fracture containment, containment,

  • Stimulation design should achieve at least 1,200 gallons

Stimulation design should achieve at least 1,200 gallons and 660 pounds per foot of gross pay stimulated (50% and 660 pounds per foot of gross pay stimulated (50% Fill Fill-

  • Up).

Up).

slide-53
SLIDE 53

2000 4000 6000 0.1 1 10 100 1,000

Effective Proppant Stress (psi)

Unpropped KfW Non-Aligned Cracks

Asperity Height Max Avg 0.26" 0.09" 0.19" 0.06"

A Residual kfw Of 1 mdft In The Un-Propped Fracture Is Likely In ETCV, However, It Depends:

  • 1. Mineralogy
  • 2. Stress State

Water Frac Guidelines Lab Tests Of Residual Fracture Width?

slide-54
SLIDE 54

y = 187.39x

  • 0.2846

R

2 = 0.9886

y = 238.54x

  • 0.3704

R

2 = 0.9769

y = 230.31x

  • 0.3877

R

2 = 0.9576

0.0 20.0 40.0 60.0 80.0 100.0 120.0 20 40 60 80 100 120

Pump Rate, BPM Propped Height, % Fill Up

10' >50' 20'

Water Frac Guidelines Pump Rate Limitations:

Width limit << BPM <<Height growth<< % Fill Up

slide-55
SLIDE 55

20 40 60 80 100 120 20 40 60 80 100 120

Pump Rate, BPM Propped Height, % Fill Up

400 gals/ft 800 gals/ft 1,200 gals/ft 1,600 gals/ft 2,000 gals/ft

Water Frac Design: % ppg 50.0 0.0 15.0 0.5 15.0 1.0 15.0 1.5 5.0 2.0 Per Foot of Pay: Fluid Prop (gals) (lbs) 400 220 800 440 1,200 660 1,600 880 2,000 1,100

Water Frac Guidelines Material Design Criteria:

Fluid Volume>1,200 gals/ft and Prop Volume >660 lbs/ft

slide-56
SLIDE 56

Summary Summary

  • Water Can Be An Excellent Inexpensive

Water Can Be An Excellent Inexpensive Fracturing Fluid Provided: Fracturing Fluid Provided:

1. 1.

Used in Low Permeability Applications, Used in Low Permeability Applications,

  • K

K h

h < 0.1 md and

< 0.1 md and K K v

v > 0.0 md

> 0.0 md

2. 2.

Some Fracture Containment Achieved, Some Fracture Containment Achieved,

  • σ

σ >>> 0.0 psi

>>> 0.0 psi

3. 3.

Unpropped Unpropped k kf

fw

w > 0.1 mdft, and F > 0.1 mdft, and FCD

CD-

  • Vert

Vert > 2

> 2

4. 4.

  • r 50% Proppant Fill
  • r 50% Proppant Fill-
  • Up Achieved,

Up Achieved,

  • 1200 gals/ft of gross pay

1200 gals/ft of gross pay

  • 660 lbs/ft of gross pay

660 lbs/ft of gross pay

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SLIDE 57
  • Introduction

Introduction

  • History of Water

History of Water Fracs Fracs

  • Water as a Fracturing Fluid

Water as a Fracturing Fluid

  • Clean

Clean vs vs Dirty Dirty

  • Residual Fracture Width

Residual Fracture Width

  • Development of Water Frac Guidelines

Development of Water Frac Guidelines

  • Reservoir Quality Considerations

Reservoir Quality Considerations

  • Geomechanical Considerations

Geomechanical Considerations

  • Fracture Design Considerations

Fracture Design Considerations

  • Water Frac Application Review

Water Frac Application Review

Water Frac Application Review: What We Know Or Think We Know?

slide-58
SLIDE 58

Water Frac Application Review Carthage Field

6000 7000 8000 8,550 8,600 8,650 8,700 8,750 8,800 8,850 8,900 8,950 9,000 9,050 9,100 9,150 9,200 9,250 9,300 9,350 9,400 9,450 9,500 9,550 9,600 9,650

P-Closure Gamma Ray

50 100

Corrected Log Using Veatch Corr.

C-Lime Stress Test Bossier Shale Stress Test Taylor Stress Test Taylor Sand

Log Data

Well Defined Geomechanical Profile!

22-9 Pcl Bossier Sh (0.83 psi/ft) WHD(psi) 3000 3500 4000 4500 5000 5500 6000 6500 sqrt(dt) 1 2 3 4 5 6 dP/d[sqrt(dt)] Isip Pext Blessed Pc 3799.855 Tc 3.227 EFFc 0.510124 Isip 6461.539 dPs 2661.684

2 4 6 8 10 2 4 6 8 10

Dynamic Modulus (MM psi)

Drained Tests for Dynamic E

  • Cotton Valley

E = 0.924 X E - 1.09

Static Dynamic

Static Modulus (MM psi)

2 4 6 8 10 2 4 6 8 10

Dynamic Modulus (MM psi)

Drained Tests for Dynamic E

  • Cotton Valley

E = 0.924 X E - 1.09

Static Dynamic

Static Modulus (MM psi)

slide-59
SLIDE 59

60 120 180 240 300 360 500 1,000 1,500 2,000 2,500 3,000 3,500 10 20 30 40 50 60 70

TIME (min) Pressure (psi)

Micro-Seismic Events

Dead String Pressure

Rate (bpm) / PPG

Rate PPG Slick Water Mini-Frac X-Link Gel Frac Step Rate Test

1 2 5 10 20 50 100 50 100 200 500 1,000

Pump Time (min) Net Pressure (psi)

Taylor Zone Mini-Frac - Nolte-Smith Plot

Data Simulation 1 2 5 10 20 50 100 50 100 200 500 1,000 2,000

Pump Time (min) Net Pressure (psi)

Taylor Zone Frac - Nolte-Smith Plot

Slick Water Data Simulation

Water Frac Application Review Validation Of Geomechanical Data

500 1000 1500 9,550 9,600 9,650 9,700 9,750 9,800

Xf (ft)

Simulation

21-10 Taylor Propped Frac

Seismic Events w/Error Depth Bars

Mini-Frac Net Pressure Match Frac Net Pressure Match w/ Micro-Seismic

slide-60
SLIDE 60

Water Frac Application Review Carthage Field 1st Stage (Taylor Sand)

Fracture Penetration (ft) 1000 2000 3000 4000 5000 74.29 min 9580 ft TVD 9610 9640 9670 Stress (psi) 6450 7550 Shale Silty 0.000 0.086 0.172 0.258 0.344 0.430 0.515 0.601 0.687 0.773 0.859 PSF psf

Vol., m ga ls Conc., p p g Ra te (BPM) Fluid Typ e Prop Type 40.0 0.0 30 TW

  • 12.0

0.5 30 TW 20/40 Ottawa 12.0 1.0 30 TW 20/40 Ottawa 12.0 1.5 30 TW 20/40 Ottawa 4.0 2.0 30 TW 20/40 Ottawa

Hydraulic Height Proppant Coverage Perforation Coverage!

Typical Water Frac Design

slide-61
SLIDE 61

Water Frac Application Review Carthage Field 1st Stage (Taylor Sand)

Modified Water Frac Design

Vol., m ga ls Conc., p p g Ra te (BPM) Fluid Typ e Prop Typ e 85.0 0.0 30 TW

  • 15.0

0.5 30 TW 20/40 Ottawa 15.0 1.0 30 TW 20/40 Ottawa 15.0 1.5 30 TW 20/40 Ottawa 15.0 2.0 30 TW 20/40 Ottawa 15.0 3.0 30 TW 20/40 Ottawa 10.0 4.0 30 TW 20/40 Ottawa

Fracture Penetration (ft) 2000 4000 6000 8000 152.61 min 9580 ft TVD 9610 9640 9670 Stress (psi) 6450 7550 Shale Silty 0.000 0.086 0.172 0.258 0.344 0.430 0.515 0.601 0.687 0.773 0.859 PSF psf

Hydraulic Height Proppant Coverage Perforation Coverage!

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SLIDE 62

Water Frac Application Review Carthage Field 1st Stage (Taylor Sand)

Why Not TW & Linear Gel?

Fracture Penetration (ft) 500 1000 1500 2000 2500 105.01 min 9575 ft TVD 9600 9625 9650 9675 Stress (psi) 6450 7550 Shale Silty 0.000 0.086 0.172 0.258 0.344 0.430 0.515 0.601 0.687 0.773 0.859 PSF psf

Vol., m ga ls Conc., p p g Ra te (BPM) Fluid Typ e Prop Typ e 25.0 0.0 30 TW

  • 10.0

0.5 30 TW 20/40 Ottawa 10.0 1.0 30 TW 20/40 Ottawa 10.0 1.5 30 TW 20/40 Ottawa 10.0 2.0 30 TW 20/40 Ottawa 10.0 3.0 30 LG 20/40 Ottawa 10.0 4.0 30 LG 20/40 Ottawa 5.0 5.0 30 LG 20/40 Ottawa

Hydraulic Height Proppant Coverage Perforation Coverage!

Hybrid Water Frac Design

slide-63
SLIDE 63

Water Frac Application Review Water Frac Application Review

Summary: Summary:

  • Long History Of Application

Long History Of Application

  • Works Well In East Texas Cotton Valley

Works Well In East Texas Cotton Valley

  • Guidelines Can Be Used For Other Applications

Guidelines Can Be Used For Other Applications

  • Hybrid TW Design Mitigates TW Frac Risks

Hybrid TW Design Mitigates TW Frac Risks

  • Hybrid TW

Hybrid TW Fracs Fracs Have Broad Application! Have Broad Application!

  • Spacers Can Aid

Spacers Can Aid Proppant Proppant Placement Placement

  • Smaller

Smaller Proppant Proppant Transports Further Transports Further

slide-64
SLIDE 64

The End

slide-65
SLIDE 65

Water Frac Guidelines Water Frac Guidelines Must Depend on Un Must Depend on Un-

  • Propped

Propped k kF

Fw

w

100 200 300 400 500 600 700 1 2 3 4

Time (days) Rate (MCFD)

Hf = 100' All = 5 k = 0.01 md Xf = 750' 80 Acres

CD

F Fully Propped Frac 20% Propped, F = 1.0

CD - Vert

10 20 50 100 200 500 1000 2000 5000 0.2 0.3 0.5 1 2 3 5

Time (days) Rate (MCFD)

Hf = 100' All = 5 k = 0.01 md Xf = 750' 80 Acres

CD

F Fully Propped Frac 20% Propped, F = 2.5

CD - Vert

20% Propped, F = 1.0

CD - Vert

Unpropped F Unpropped f Vert CD

H k w k F

− −

= ) (