IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Storage 4 - Modeling for CO2 Storage
Professor John Kaldi Chief Scientist, CO2CRC Australian School of Petroleum, University of Adelaide, Australia
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Modelling
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
On Models .…
• There is no substitute for: • Critical independent evaluation on the part of
the geoscientists and engineers to assure the success of a modeling project.
Most failures occur because a basic assumption was found to be wrong.
“All models are wrong…. some are useful” George Box
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Modelling for CO2 Storage • Modeling is used to: – Design injection (location and number of wells,
– Forecast the migration of injected carbon dioxide
– Simulate fluid flow
– Estimate storage capacity
– Predict reservoir response
– Know when and where to monitor
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
• Modeling can include: – coupled geochemistry;
– coupled geomechanics;
– tracer migration.
• Other benefits of modeling – Ascertain uncertainty
– Impress stakeholders: communication tool
• Most modelling uses computer models
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Modelling for CO2 Storage
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Computer models for CO2 Storage
• Computer models usually: – solve the multiphase equations for fluid flow in porous
media;
– use finite-difference techniques for solving flow equations;
– require the simulated region to be broken up into grid blocks
– are based on techniques and code developed in the petroleum industry over the past 4 decades.
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Simulation grid
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Discretisation & parameterisation
Each grid block only has one value for porosity, permeability, saturation, composition etc. This has two important consequences:
• We cannot resolve anything in the results below the size of a grid block, i.e. may need to refine grid in areas of interest.
• Geological data measured on different scales e.g. core data, has to be “upscaled” or averaged in an intelligent way.
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Upscaling
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
3D representation(s) of the subsurface
Each cell contains values for geographic position, depth, volume, rock type, poro/perm, and other “static” properties. Size and complexity important
Grid resolution a key decision: trade-off between detail vs. computational limits.
The 3D static geological model
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
The Basics: Static (Geological) Modelling Aim: Capture effects of structure, stratigraphy, sedimentary architecture
– Reservoirs and seals – Lateral and vertical scale & heterogeneity – Faults & fractures – petrophysical properties (porosity, permeability, seismic) – Fluid properties
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Input data types Hard Data: Direct measurement from the subsurface: • Cores (metres), • cuttings (a few mms), • Plugs (10s cms) • fluid samples…
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Integrated data for reservoir characterisation & modelling
-Dep. Env. - Poro/Perm - Stratigraphy
Core data
Outcrop Analogs - Stratigraphy - Geometry
Seismic
Static model
Wireline log data (correlate between wells)
Dynamic (Res Sim) model
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Reservoir Simulation: Dynamic Models
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Simulation input and output
• Input: – Static model (permeability, porosity, fault boundaries…) – Dynamic properties (relative permeability, capillary
pressure) – Initial conditions (pressure, temperature,…) – Boundary conditions (aquifer drive, …) – Flow rates at wells
• Output: – Maps of pressure, fluid saturation, …. – Tracer concentration (if implemented) – Dissolved components (if implemented) – Chemical reaction products (if implemented) – Stress and strain (if implemented in a geomechanical
model)
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
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Dealing with uncertainty: requirement for Probabilistic Modelling
Multiple Interpretations
Data Scarcity
Reservoir Heterogeneity
Data “Fuzziness”
Stochastic Model
Need Probabilistic Approach
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Uncertainty
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Models should be fit for purpose
1. To address scientific questions in a generic context e.g.:
– the effect of shale barriers on vertical migration of CO2
– the effect of a hydrodynamic gradient on CO2 migration
– Dissolution of CO2
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
40 yr
130 yr
330 yr
From: J. Ennis-King
Modelling the dissolution of injected CO2
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
900 yr
1300 yr
2400yr From: J. Ennis-King
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Modelling the dissolution of injected CO2
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Models should be fit for purpose
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2. To make technical predictions in a site-specific context to support decisions e.g.:
- What is CO2 breakthrough time in a deep injection EOR project?
- What is effect of well-spacing on maximum injectivity?
- What is the predicted seismic response? Image source: http://www.iogsolutions.com
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Models can be simple...
rc,max
h
h(r,t)
q
Nordbotten et al. (2005)
e.g. Analytical models
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
…or more complex
Reference: Flett, M. A., et al. (2008) SPEdoi:10.2118/116372-MS
Example from Gorgon Project:
• Inject and store 3-4 MT PA
• Long-term modelling and monitoring
Solves a large set of linear equations at a number of given time-steps for a large number of cells
•Computationally demanding
•“Coupled” geochem / geomech
e.g. 3D Numerical Models
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Anderson & Woessner (1992)
Basin-scale vs Small-scale (pilot) projects
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Solve a large set of linear equations at multiple time-steps for a large number of cells in a broad geographic area -Computationally demanding
Make technical predictions in a site-specific context to aid decision-making -Computationally manageable
500m
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
CO2 injection
well
Image from: C. Gibson-Poole
Modelling injection and migration of CO2 Kingfish Field, Gippsland Basin, Austtralia
Lakes Entrance Formation
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
CO2CRC Otway Project
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
The CO2CRC Otway Project
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• Geological model: incorporates structure (faults) & fluid contacts
• Static model
- based on: facies (rock-type) grid parameterization
- Stochastic: multiple realisations of properties (eg porosity, permeability)
• Dynamic model:
upscaled; simulates various injection / migration scenarios
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
CRC-1 Injector Naylor-1 Monitor well
Naylor South-1
0 300m
Pre-production gas spill point
-2140 -2120 -2100 -2080 -2060 -2040 -2020 -2000 -1980
Depth mSS
T.Dance
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
T.Dance
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Screen grab of 3D model looking West.
Naylor South Fault Injection zone in contact with Timboon Aquifer
Geo-cellular model Details: •10x10m lateral cell size •Layers ~1m
•Total cells: 132,396
•Layers follow top
•5 Realisations of sands and shale •Poro/perm conditioned to facies
CRC-2 Naylor-1
CRC-1
Porosity T.Dance
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Screen grab of 3D model looking West.
Naylor South Fault Injection zone in contact with Timboon Aquifer
Geo-cellular model Details: •10x10m lateral cell size •Layers ~1m
•Total cells: 132,396
•Layers follow top
•5 Realisations of sands and shale •Poro/perm conditioned to facies
CRC-2 Naylor-1
CRC-1
Permeability T.Dance
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
CO2 injection well
Monitoring well
CO2 accumulation
Upscaled Reservoir Model
Y.Cinar
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
CO2CRC Otway project: CO2 mass fraction
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Carbon dioxide mass fraction: 18 Sept Carbon dioxide mass fraction: 31 Dec
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
CO2CRC Otway project: pressure difference
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Pressure difference: 18 Sept – 31 Dec Pressure difference: 18 Sept – 31 Dec (NW – SE slice)
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
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Modelling Time and effort
(from Tyson, 2008)
IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016
Modelling Conclusions
• Modelling is a useful tool in the design of carbon dioxide storage projects.
• Modelling depends on the quality of the data and the skill of the user (old saying: garbage in, garbage out).
• Most effort and time in modelling is in data gathering and grid parameterization
• In the right hands with correct questions it can provide powerful answers.
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IEAGHG CCS Summer School Regina, Sask., Canada, 17-22 July, 2016 37
Questions?
© CO2CRC 2015