Task 4: Stimulation Economics and PWRI

1
Task 4 StimulationEconomics and PWRI

• TerraTek, Inc.
• Heriot -Watt University
• Triangle Engineering
• Duke Engineering and Services, Inc.
• eFirst Technologies
• Gas Research Institute
• Advantek, International, Inc
• VIPS

2
PWRI
Data
3
PWRI and Economics
Data
Cost
Cost
Issues
Confirm / Revise / Develop Technical Methods
Other Company Contacts / knowledge
Experience Database
Best Practices
Software
Toolbox
Cost
Cost
4
PWRI, Economics and Stimulation
Data
Cost vs Benefit
Risk
Issues
Confirm / Revise / Develop Technical Methods
Other Company Contacts / knowledge
Experience Database
Best Practices
Software
Toolbox
Risk
Cost vs Benefit
5
Drivers for Produced Water Re-Injection
WATER INJECTION DRIVERS
Options
Purposes
PWRI
PWRI DRIVERS
- Need Additional Injection Water -
Environmental Issues - Company Policy -
Legislation - Other
Produced water disposal
Disposal zone
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Water Injection

• Lowest cost water source used early in project
  life
• Produced Water becomes available later on
• Additional surface facilities/equipment normally
  required for move to PWRI operation.
• Opex e.g. pump maintenance will change
• Facilities operation mode will be decided by
  cost/benefit analyses (e.g. commingled or
  separated injection)
• Higher pressure pumps, new or converted wells may
  be required in order to re-inject increasing PW
  volumes

PWRI Economics - The Way Ahead Next Presentation
(Paul Van Den Hoek)
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PWRI Project - Decision Tree
OK
Additional injection wells required (new/converted
)
Cost
Injection Processin operation (SW/AW)
Yes
Yes
Enough Injection Wells ?
Not yet
No
Conversion / Addition of surface facilities
PWRI Required (at later stage)?
Commingled
Water for early injection?
Yes
Operation mode(cost/benefitanalysis)
Yes
Cost
Sufficient pump capacity?
No
PW available?
No
Higher Pressure pumps
Addition of PWRI System
Segregated
Cost
Cost
8
Water Injection

• Lowest cost water source used early in project
  life
• Produced Water becomes available later on
• Additional surface facilities/equipment normally
  required for move to PWRI operation.
• Opex e.g. pump maintenance will change
• Facilities operation mode will be decided by
  cost/benefit analyses (e.g. commingled or
  separated injection)
• Higher pressure pumps, new or converted wells may
  be required in order to re-inject increasing PW
  volumes

PWRI Economics - The Way Ahead Next Presentation
(Paul Van Den Hoek)
9
PWRI - Technical Cost Implications

• Can we generate a planning figure for loss of
  injectivity due to conversion to PWRI (e.g. 20)?
• It depends on formation, thermal effects water
  quality (oil/solids) e.g. PEA 23 equation
• Risks e.g. what are the disposal alternatives of
  the produced water if injectivity is insufficient?

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PWRI - Impact Injectivity Damage
OK
No
Yes
On going damage ?
No Damage
Good
Additional water treatment facilities
Cost
Intermittent?
Water Quality?
Yes
No
Higher Pressure pumps
Cost
Injection Loss fully recovered ?
Poor
Damage?
Yes
Additional injection wells
Cost
No
(Repetitive) Chemical Stimulation
Cost
Facility Options
Net Cost
Mechanical Stimulation
Stimulation
Cost
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PWRI - Technical Cost Implications
Injectivity
Time
12
Water Management

• What is value of extra water injected
• Water needs to become a tangible benefit in terms
  of pressure support / sweep rather than just a
  cost
• Understand Interplay between water injectors and
  producers (also required for Intelligent
  Injectors)
• Where can a limited amount of injection water be
  most beneficially used
• (New) flowstream representation of reservoir
  simulation results (e.g. FLOWVIS from Geoquest)
  simplify this

13
What is lowest cost / least risk option?

• Cost Example from data base (1)
• Corrosion Management
• Deferred oil

14
Cost Example from data base (2)

• Bypass part of water treatment system?
• Costs in Million / year
• What happens during plant upset

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PWRI - Technical Cost Implications

• Option 1 Costs of Mitigation
• Derive from Paul Van Den Hoeks proposal for
  PWRI Economics - the Way Ahead
• Option 2 Stimulation treatments needed to
  restore injection
• How do we define success?

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Is stimulation the lowest cost option?
ELF PICTURE

• Compare costs continuing damage acid stimulation

17
Is stimulation the lowest cost option?
ELF PICTURE

• Include risk of technical failure!

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Is stimulation the lowest cost option?
ELF PICTURE

• Compare costs continuing damage acid stimulation

19
PWRI - Techno / Economic Evaluation

• How do we define success?
• Qualitative view (Extremely / Yes / No)
• Achieve short term injection target often
  critical
• Recognise other well / injection system
  limitations
• (discounted stimulation index based on Hall
  plot? - see next slide)
• Economics concentrate on extra water injected
  compared to do-nothing base case? (i.e.
  similar concept as used for evaluation of
  production well stimulation)

20
Stimulation Economics - The Way Ahead

• Prepare best practice using Stimulation Index
  based on value of discounted net extra water
  injected
• Compare with cost of stimulation and other
  mitigation strategies
• Include stimulation in any larger study (Use
  same methodology)
• Request typical costs for most complete wells
  in database

21
PWRI - Technical Cost Implications
22
Repetitive Acidising of Sandstones

• Often shows decreasing success
• Damage Location - Placement techniques
• Stimulation fluid selection