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DEVEX 2014
Checking complex
geomodel and simulation
workflows
Mark Hayes: Head of
Reservoir Engineering RPS
Energy
7th May 2014
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• Introduction
• Reservoir Simulation QC
– Analytical Models
• Field Examples
– Heavy Oil
– Pre & Post Development
– Use of Analogues
– Heterogeneous Producing Fields (Brent)
– Undeveloped Discoveries
• Conclusions
Outline
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Introduction
• Moore's law is the observation that, over the history of computing hardware, the number
of transistors on integrated circuits doubles approximately every two years.
• Seeing impact in subsurface workflows, multiple scenario workflows, very fine grids ….
• BUT ?
M&A short timescale evaluations
Reserves Report / Audit Bank financing ?
Internal corporate assurance
Non operated Working Interest …
VIP vs Eclipse …CMG …
IF I RUN YOUR RESERVOIR MODEL ON MY COMPUTER WHAT AM I DOING ????
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Reservoir Simulation
Simulation
Model
Static Description
• Porosity
• Permeability
• Net-to-Gross
• Compressibility
Fluids
• Oil
• Water
• Gas
Rock/Fluid Interaction
• Relperms
• Capillary Pressure
Initial Conditions
• Fluid contacts
• Initial pressures
• Initial saturations
Pressure Support
• Aquifer
• Formation
Compressibility
Production/Injection
• Well locations
• Perforations, stimulation,
workovers etc
• Production/injection rates
• Well pressures (THP, BHP)
• Well performance tables
Simulation
Model
Static Description
• Porosity
• Permeability
• Net-to-Gross
• Compressibility
Fluids
• Oil
• Water
• Gas
Rock/Fluid Interaction
• Relperms
• Capillary Pressure
Initial Conditions
• Fluid contacts
• Initial pressures
• Initial saturations
Pressure Support
• Aquifer
• Formation
Compressibility
Production/Injection
• Well locations
• Perforations, stimulation,
workovers etc
• Production/injection rates
• Well pressures (THP, BHP)
• Well performance tables
Simulation
Model
Static Description
• Porosity
• Permeability
• Net-to-Gross
• Compressibility
Fluids
• Oil
• Water
• Gas
Rock/Fluid Interaction
• Relperms
• Capillary Pressure
Initial Conditions
• Fluid contacts
• Initial pressures
• Initial saturations
Pressure Support
• Aquifer
• Formation
Compressibility
Production/Injection
• Well locations
• Perforations, stimulation,
workovers etc
• Production/injection rates
• Well pressures (THP, BHP)
• Well performance tables
Simulation
Model
Static Description
• Porosity
• Permeability
• Net-to-Gross
• Compressibility
Fluids
• Oil
• Water
• Gas
Rock/Fluid Interaction
• Relperms
• Capillary Pressure
Initial Conditions
• Fluid contacts
• Initial pressures
• Initial saturations
Pressure Support
• Aquifer
• Formation
Compressibility
Production/Injection
• Well locations
• Perforations, stimulation,
workovers etc
• Production/injection rates
• Well pressures (THP, BHP)
• Well performance tables
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• Applicable in water flood, particularly when heterogeneity and/or mobility is a challenge
• Think about ……
– MOBILITY RATIO
– GRAVITY FORCES
– HETROGENIETY
• Buckley Leveret (homogenous / unfavourable mobility)
– Diffuse & Segregated
• Layered Systems
– Stiles – permeability - flooding order perm dominated
– Vertical Equilibrium – gravity dominated
Fractional Flow
Gravity Heterogeneity
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Best Reference DAKE / Elsever
Best Tool ? Water Drive …
www.petroleumsolutions.co.uk …
OR EXCEL ….!
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Buckley Leveret Stiles (k perm order) Vertical Equilibrium
Fractional Flow Models
10 mD
100 mD
1 mD
10 mD
Fw
Np/N
Increase in Uo
Fw
Np/N
Or Base (hi perm) top
Fw
Np/N
Increase in Uo
Increase in Uo
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Field A – Heavy Oil Development
• Objective
– Validation of ECLIPSE simulation model profiles & reserves using simple Analytical models
– 24 – 48 hr run times on multi processor server
– Every ECLIPSE option in the book !
• Mobility Ratio Critical to estimating Rf
– very unfavourable mobility ratio uo ~ 500 cp M ~ 223
• Buckley Leveret single layer Analysis
– Generic Corey Rel Perm Curves
– Long Drilling Program with phases
– Sector models for phasing…
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0
5000
10000
15000
20000
25000
30000
35000
40000
Oil R
ate
barr
els
per
day
Oil Rate Comparison
Analytical Model Simulation Model
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0
50000
100000
150000
200000
250000
300000
mb
w/d
Water Production
Analytical Simulation
Horizontal
well /
Zonal
Isolation
benefit ?
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• Scope
– Validate satellite discovery forecast
– Main field production history available
• Workflow
– Used available core data
– Digitized from Plot from PDR
– Routine STILES analysis
• Kro = 0.7 krw = 0.3
• Uo = 0.9 Cp
– Matched Fw to offset field performance
– Good match to late field performance given known STOIIP
– Revised STILES model for Discovery
• PVT (higher oil viscosity)
• STOIIP
Field B – Satellite Discovery
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Poor early
wells not
accessing
all STOIIP
Horizontal
well
benefit ?
Good
match
Most PV
contacted
Based on
Known
STOIIP
Match to late field performance
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Discovery Match to Simulation Model
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
Oil Rate
Analytical Simulation
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0
10
20
30
40
50
60
70
1 10 100
RF
%
Viscosity (cp)
field 1
field 2
field 3
Analogues
Stiles -homogenous
Stiles - modhetrogeneous
Field C – Heavy Oil Analog Example
Scope: Benchmark
deepwater heavy
oil development
Limited production
data
Key issue oil
viscosity & mobility
Integrated analog
and simple stiles
flow model using
available core
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Conclusions
• Computing power is leading to many Fine Grid & Complex models
• These can be difficult to Review and QC.
• Still Room for complementary analytical models
– Can given surprisingly accurate results
– Useful in North Sea given strong Waterflood presence
– Particularly when heterogeneity AND/OR mobility level are unfavourable & dominate
– Analytical models may tend to overstate “mid life” water production rates
– Can be linked to facilities constraints
– 1 dimensional model Cannot help with detail
• Development Well location & geometry
• Infill Drilling …
Forecast
An
alo
gu
e