british geological survey/ncccs – the long-term fate of co2 in the subsurface environment
DESCRIPTION
Professor Mike Stephenson, Head of Science (Energy) at the British Geological Survey (BGS) leads a Global CCS Institute webinar on the long-term fate of CO2 in the subsurface environment.TRANSCRIPT
GLOBAL CCS INSTITUTE
The long-term fate of CO2 in the subsurface environment Mike Stephenson and Jonathan Pearce
British Geological Survey/Nottingham Centre for CCS
WWW.GLOBALCCSINSTITUTE.COM
GLOBAL CCS INSTITUTE
MIKE STEPHENSON
1
Head of Science (Energy) at the British
Geological Survey (BGS)
- Professor Stephenson runs the Energy
Programme at BGS including carbon
capture and storage, hydrocarbons,
renewables and unconventional energy
- Director of the Nottingham Centre for
Carbon Capture and Storage, a joint venture
between the BGS and the University of
Nottingham.
- Mike earned a BSc, MSc and PhD from
the University of Sheffield and Imperial
College, London as well as various
postgraduate teaching qualifications.
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JONATHAN PEARCE
2
Job Title at Organisation
-Jonathan Pearce, over 24 years experience
with BGS.
-Involved in CO2 storage research since the
early 1990s and has led a number of
research projects on long-term geochemical
processes and the development of shallow
monitoring tools in CO2 Storage.
-His research has allowed him to collaborate
with other researchers globally including in
China, Australia, Canada, South Africa and
widely across Europe.
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THE LONG TERM
FATE OF CO2 IN
THE
SUBSURFACE
ENVIRONMENT
Mike Stephenson
Jonathan Pearce
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GLOBAL CCS INSTITUTE
RELEVANT TO
• Regulation
• Public confidence
• Investment
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GLOBAL CCS INSTITUTE
VERY IMPORTANT
Building the three-dimensional static geological earth model
Using the data collected in Step 1, a three-dimensional static geological earth model, or a set of such models, of
the candidate storage complex, including the caprock and the hydraulically connected areas and fluids shall
be built using computer reservoir simulators. The static geological earth model(s) shall characterise the
complex in terms of:
(a) geological structure of the physical trap;
(b) geomechanical, geochemical and flow properties of the reservoir overburden (caprock, seals, porous and
permeable horizons) and surrounding formations;
(c) fracture system characterisation and presence of any human-made pathways;
(d) areal and vertical extent of the storage complex;
(e) pore space volume (including porosity distribution);
(f) baseline fluid distribution;
(g) any other relevant characteristics.
Regulation and public confidence
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BASICS OF
STORAGE
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GLOBAL CCS INSTITUTE Basics of long term storage
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GLOBAL CCS INSTITUTE Basics of long term storage
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STORAGE AND
TIME
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GLOBAL CCS INSTITUTE
TIME
„Free CO2‟
Dissolved CO2
Carbonate minerals
Storage and time
Physical trap
Solubility trap
Mineral trap
Time =?
Time =?
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GLOBAL CCS INSTITUTE
CO2
Physical trap Storage and time
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CO2
Physical trap: pressure in a closed system
Storage and time
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GLOBAL CCS INSTITUTE Physical trapping: simulation
Storage and time M
GLOBAL CCS INSTITUTE
CO2
After 3 power stations per year (30mt/yr) for 50 years.
The first 50 years
Storage and time
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Pressure – open system
The first 50 years
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PRESSURE: ‘CLOSED’ SYSTEM
Storage and time
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CO2 injection starts
free CO2
The first 1780 years: free CO2
Storage and time M
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1999 (2.3 Mt) CO2 reaches top of reservoir. First repeat survey 2001 (4.3 Mt) Second repeat survey 2020 (20 Mt) Injection ceases 2070 2270
free CO2 CO2 in solution
[courtesy Erik Lindeberg, SINTEF]
Solubility trapping : Sleipner, the next 275 years
Storage and time: effects of impurities on solubility? J
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0 s 60 s 90 s 105 s 120 s 135 s 150 s 195 s 255 s
Lab dissolution experiment
Free CO2
Saline water
[BGS Hydrothermal Laboratory] Storage and time J
GLOBAL CCS INSTITUTE
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HOW COULD WE DEFINE „LONG TERM‟?
• Approaches to defining appropriate time scales of post-closure:
– When complete dissolution of CO2 occurs?
– When stability of CO2 migration is reached? (creation of CO2 reservoir)
– When a “new” THMC equilibrium is reached? (steady- state regime)
When...?
Complete dissolution
Stabilisation
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CONFORMITY WITH MODELS • Any assessment of permanency will rely on models
– Hence the validity of static and dynamic models is critical
• Validity and robustness is tested by comparing model predictions with
past monitoring data (so-called history-matching)
• Suggested tests:
– A model matches historical flow/pressure data to within x% of the
actual measured data.
– If a static model has not been revised over e.g. 5 years, and still
adequately enables predictions to match monitored performance,
then the static model may be considered robust and representative.
• Key issues are:
– What is adequate? (e.g. within 5% or 10%?)
– The acceptable range deemed to meet measurements will vary with
parameter and is likely to be specified as a condition of the storage
permit
– What if there is more than one unique solution?
– Updates to models should be expected as more data is obtained J
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CONFORMITY WITH MODELS
• Models used to predict future performance
should be those that have been used during site
characterisation and development of monitoring
plan (subject to approved revisions)
• The regulator might want to review the changes
undertaken to models during the project
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Things go
down....
CO2
mineralises..
Dissolution? mineralisation J
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DEMONSTRATING LONG-TERM
STABILITY
• Model scenarios should be conservative –
parameters should be far from expected values
(e.g. 2δ)
• Define acceptable % deviation from stable value
(5-10%)
• Models predict eventual stability of the plume
with no evidence of potential future leakage
• Key monitored parameters should be within a
predetermined range to the future stable values
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CONCLUSIONS
• Key trapping mechanisms are:
– Physical containment
– Residual trapping
– CO2 dissolution
– Mineral trapping
• Demonstrating long-term performance is
fundamental to transferring long-term liability to the
State.
• Storage risk goes down with time
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GLOBAL CCS INSTITUTE
ACKNOWLEDGEMENTS
Sam Holloway (BGS)
Andy Chadwick (BGS)
Mercedes Maroto-Valer (NCCCS)
Sarah Mackintosh (NCCCS)
Antony Benham (NCCCS)
Sarah Hannis (BGS)
John Williams (BGS)
Andy Newell (BGS)
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QUESTIONS
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You can submit questions
to us simply by typing
your question directly into
the GoToWebinar control
Panel.
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Mike Stephenson, Kathy Hill, Jonathon Pearce
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