This Presentation Will: 1. Introduce a new way of evaluating reservoir uncertainty with RESASSURE 2. Illustrate the concepts used 3. Highlight the benefits achieved 4. Demonstrate the value of the results Stochastic Simulation has unleashed the world’s fastest reservoir simulator, ResAssure, which is set to revolutionize production planning and reserves reporting in the Oil & Gas industry. ResAssure easily computes > 1 Million realisations within a 24 hour period, a fraction of the time it currently takes with traditional methods and software packages. The release of ResAssure marks a significant milestone in the history of reservoir simulation – the first real industry technology advance in 30 years. Dr Wadsley, Chief Technology Officer at Stochastic Simulation, commented “ResAssure is capable of quickly generating more accurate reserve estimates than is currently possible by any other software system. The approach taken generates a complete distribution of history matched models all of which are consistent with the geological model and observed production history. The time taken for this is orders of magnitude faster than current history matching methods.” “Field development planning based on ResAssure’s distribution of models (rather than just upon a single history-matched model using conventional methodologies) will significantly reduce uncertainty and risk.” he added. By enabling faster and more accurate analysis of dynamic subsurface geological data than has previously been possible, ResAssure markedly reduces the risk in the development of oil and gas fields by narrowing the range of uncertainty in reserves estimates: thereby supporting better production and financing decisions, with substantial increases in project ROI. ResAssure’s innovation in reservoir simulation solves fully-implicit, dynamic three-phase fluid flow equations for every geological realisation. The speed breakthrough was achieved by a combination of proprietary algorithms, polygonal gridding and aggressive spatial coarsening and time stepping, based upon a conventional finite-difference discretization of the reservoir. Key Insights Identified: 1. Consistency between volumetric, material balance and fractional flow places very strong constraints on feasible reservoir models. 2. The mathematics of reservoir simulation is NOT complex – it is the geology which is complex. 3. Reserves uncertainty is not quantified, but estimated from current ‘best’ estimate in an ad hoc unsystematic way. 4. What’s the point of preserving mass balance in the simulator when the hydrocarbons in the reservoir are imprecise and we don’t include all production data – mass balance should act to regularise our solution, not to define it. 5. The role of reservoir simulation is not to compute an exact solution of a poorly defined geological model – it is to define a range of feasible reservoir models and associated production forecasts.

1. ResAssure
A Revolution in Reservoir Simulation and
Uncertainty Modelling
www.StochasticSimulation.com

2. Presentation outline
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ResAssure – An introduction
Philosophy
Where ResAssure fits into Reservoir Simulation
Driving ResAssure from Eclipse
Some Examples
Stochastic Simulation
Copyright © 2013
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3. What is ResAssure?
ResAssure is a revolutionary reservoir simulator integrated
closely to the latest MCMC techniques providing rigorous
subsurface quantification
Stochastic Simulation
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4. Why ResAssure is a revolution?
• It achieves incredible reservoir simulation speeds (~1000
times) compared to any conventional reservoir simulator
• It’s based on a significant innovation in numerical solution
techniques
• It is not a proxy solution
• It provides fully implicit solutions for every geological
realization
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5. What is Stochastic Simulation?
• Evaluating very large numbers of simulation outcomes
and obtaining probabilistic forecast distribution in the
presence of uncertainty
• Stochastic simulation of hydrocarbon reserves:
– Narrows the range of uncertainty in reserves estimation
– Better information for production and financing decisions
– Reduces the potential for over- or under-investment
• Learn about Stochastic Reservoir Engineering
Stochastic Simulation
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6. Outline of Presentation
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•
•
•
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ResAssure – An introduction
Philosophy
Where ResAssure fits into Reservoir Simulation
Driving ResAssure from Eclipse
Some Examples
Stochastic Simulation
Copyright © 2013
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7. Key Insights
• Consistency between volumetric, material balance and fractional
flow places very strong constraints on feasible reservoir models
Stochastic Simulation
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8. Consistency: Material Balance Constraints
Volumetric
GRV, Structure,
Porosity, Net-sand,
Sw, GOC, OWC
Material Balance
PVT, Aquifer Influx
Compressibility,
Pressure Response
Well Production
Fractional Flow
Water-Cut, GOR
Stochastic Simulation
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9. Key Insights
• Consistency between volumetric, material balance and fractional
flow places very strong constraints on feasible reservoir models.
• The mathematics of reservoir simulation is NOT complex – it is the
geology which is complex.
Stochastic Simulation
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10. Complexity
Percussionists at the Beijing Olympics – impressive but not complex
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11. Complexity
Geological complexity is the main driver of reserves uncertainty
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12. Key Insights
• Consistency between volumetric, material balance and fractional
flow places very strong constraints on feasible reservoir models.
• The mathematics of reservoir simulation is NOT complex – it is the
geology which is complex.
• Reserves uncertainty is not quantified, but estimated from current
‘best’ estimates in an ad hoc unsystematic way.
Stochastic Simulation
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13. Reserves evolution with time
Wormhole of Reality
Stochastic Simulation
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14. Zone of Consistency
Low Consistency
Low Certainty
Most Likely Outcome
Medium Consistency
Medium Certainty
Volume
Pressure
High Consistency
High Certainty
Production
ResAssure finds the “Zone of Consistency”
Stochastic Simulation
Copyright © 2013
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15. Outline of Presentation
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•
•
•
•
ResAssure – An introduction
Philosophy
Where ResAssure fits into Reservoir Simulation
Driving ResAssure from Eclipse
Some Examples
Stochastic Simulation
Copyright © 2013
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16. The Wheel of Reservoir Simulation
Model Application
(reserves estimation and
production forecasting)
Spatial & temporal
upscaling
Definition of
model structure
Model Formulation
Model
Characterisation
Implementation
Consistency checks,
parameter estimation
& data constraints
Data
Independent data &
analogue studies
Fit-for-purpose
Assessment
Validation
Stochastic Simulation
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Plausibility & evaluation
of uncertainty
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17. ResAssure Workflow Position
Seismic
Interpretation
Production Data
Geological
Modelling
Single Reservoir
Model
(Petrel, RMS)
Reservoir Simulation
Model
(Eclipse, Tempest)
History Matching
Experimental Design
(Cougar, EnABLE)
“P90” “P50”
Lo
“P10”
Mid
Stochastic Simulation
(ResAssure)
Full Distribution of
Reservoir Models
• ResAssure leverages existing systems
Stochastic Simulation
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Probability
Reserves
Hi
E
X
I
S
T
I
N
G
Reserves
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18. What Parameters Can Be Included?
Geophysics, Geology & Petrophysics
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Depositional environment
- Geo Statistical property interpolation
- Facies and rock types
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Structure, seismic picks, layer thickness
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Fault position
•
Net-gross, porosity, permeability, fluid saturation
Well Production Matching
Fluid System
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Matrix-fracture transmissibility
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Fractional flow
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Fault transmissibility
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Decline curves
•
Fluid / rock compressibility
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Oil, gas and water production
•
Aquifer recharge
•
Region and Well Pressure
•
Fluid Contacts
•
PVT properties
•
Relative permeability end-points
Stochastic Simulation
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19. Comparison
ResAssure
Experimental Design/Proxy Surface
• 100,000’s realisations
• full 3D simulation for every
realisation
• ~1000 times faster than conventional
simulators
• 100’s of perturbation modifiers can
be simultaneously analysed
• Any reservoir property can be
included as all perturbations built
into simulation engine
• Multiple methodologies for exploring
space of realisations
• Limited number of full 3D
realisations
• Accuracy limited to resolution of
proxy surface
• Workflow time constrained by that
of conventional simulator run time
• Proxy surface resolution and
exploration of parameter space
limited by ‘curse of dimensionality’
• Modifications limited by model
building work-flows
Stochastic Simulation
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20. Outline of Presentation
•
•
•
•
•
ResAssure – An introduction
Philosophy
Where ResAssure fits into Reservoir Simulation
Driving ResAssure from Eclipse
Some Examples
Stochastic Simulation
Copyright © 2013
20

21. ResAssure Workflow
Eclipse DataDeck
(or other format)
Convert to ResAssure
format
Review Model/Geology
View Results
Stochastic Simulation
Select Perturbations
Launch ResAssure
(using Amazon Web
Services)
Run Multiple
Realisations
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22. Perturbation Selection
Parameters are assigned to reservoir regions:

Equilibration

PVT

Fluid in Place

Saturation
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Boolean combinations (intersection/union) of these
Each parameter is assigned:

Minimum

Maximum

Perturbation / Step Size

Probability Distribution (MCMC)

etc
Stochastic Simulation
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23. Cloud Computing (Amazon Web Services)
• ResAssure – A Practical Solution
– Currently, small to medium simulations running on a single
thread generate approximately 500 ~ 2500 realisations / hour
– Parallelisation on an 4 core high performance CPU realises
almost linear speed-up to ~ 10000 realisations / hour
– 24 hours of computing can generate > 100,000 realisations, each
of which is a valid history-match or reservoir forecast
This simulation speed is sufficiently fast to enable the working
reservoir engineer efficient turnaround of stochastic simulation
solutions within the working day.
Stochastic Simulation
Copyright © 2013
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24. How is this speed achieved?
• ResAssure provides fully implicit simulation realisations
without using proxy or approximation techniques
• The speed breakthrough is achieved by:
– proprietary algorithms
– polygonal gridding
– aggressive spatial coarsening and time stepping
• Fast history matching is achieved when the mismatch
function (the difference between observed and calculated
well rates and pressures) is accepted within error
tolerance
Stochastic Simulation
Copyright © 2013
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25. Outline of Presentation
•
•
•
•
•
ResAssure – An introduction
Philosophy
Where ResAssure fits into Reservoir Simulation
Driving ResAssure from Eclipse
Examples
Stochastic Simulation
Copyright © 2013
25

26. Higher dimensional sampling
Mismatch function calculated for > 90,000 realisations using
trajectory sampling showing > 15 distinct minima (history-matches)
Stochastic Simulation
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27. History matching
Cross plots of kvkh, porosity and depth versus permeability for
best 800 history-matches
Each trend-line represents
different history-match
Stochastic Simulation
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28. Geological sensitivities
Conventional History-Match cannot distinguish between downside
and upside cases
Downside Case
Stochastic Simulation
Upside Case
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29. Geological sensitivities
Section showing upside and downside top structure
“Flex” between upside and downside structure maps
Stochastic Simulation
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30. Geological sensitivities
Stochastic Simulation showing degree of flexing between
Upside Case (-1.2) and Downside Case (0.4)
Stochastic Simulation
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31. Geological sensitivities - Results
Most likely top structure is biased towards upside case
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32. Get in touch
To register your interest in ResAssure click here
Suite 3, 85 Guthrie Street, Osborne Park, Perth, WA, 6017
+61 (08) 9446 2099
info@stochasticsimulation.com
www.stochasticsimulation.com
This project has been supported with assistance from the
Australia Government through Commercialisation Australia.
Stochastic Simulation
Copyright © 2013
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33. Copyright © 2013