1. Neil Wildgust
BASICS OF GEOLOGICAL STORAGE
Global CCS Institute
WORKSHOP FOR CIVIL, CHEMICAL, ELECTRICAL, ENVIRONMENTAL AND MECHANICAL ENGINEERS:
INTRODUCTION TO CAPTURE, USE AND GEOLOGICAL STORAGE OF CO2
October 13-14, 2014
DF CFE Technology Museum
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2. Geological Storage Scenarios
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3. Effective Storage in Dense Phase
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4. Trapping Mechanisms
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5. Structural and Stratigraphic Trapping
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6. Seals or Caprocks
• Principal types – shale and salt
• Shales:
• Clay-rich rocks
• Variable, low permeability
• May allow slow migration of formation brine to alleviate
pressurization
• Salts:
• Extremely low permeability
• Combined with ductile properties – very secure caprock
• Negligible scope for brine migration and pressure
alleviation
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7. Residual Trapping
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8. Solubility Trapping
• CONTROLLING FACTORS:
• Temperature
• Pressure
• Brine salinity
• Hydrogeological systems
• Effects of reservoir
heterogeneity
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9. Mineral Trapping
• Potentially most secure
trapping mechanism
• Variety of minerals can
precipitate
• Long and uncertain
timescales
• Modelling complexity
• e.g. reservoir
heterogeneity
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10. Characterization Methods
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11. Seismic Surveys
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12. Predictive Modelling
• Regulatory requirement
• Based on existing
knowledge e.g. reservoir
engineering, hydrogeology
• Flow simulations can be
coupled with other
processes e.g.
geochemistry,
geomechanics etc
• Iterative process – re-calibrate
with monitoring
data
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13. Measurement, Monitoring and Verification
(MMV)
• May be focused on the
reservoir or for
environmental protection
• Suite of existing
technologies available –
choice should be site-specific
• Baseline (pre-operational)
data required
• Cost-effective approaches
for commercial
deployment
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14. Risk Assessment
• Regulatory requirement
• Framework for project
assessment and
management
• Integrity of storage is
paramount consideration
• Key risk scenarios for deep
aquifers include capacity
and injectivity
• Key risk scenario for CO2-
EOR is wellbore integrity
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15. Storage Costs
• Generally regarded as significant but minor portion of
overall costs for whole chain CCS
• Usually quoted in $/tonne (or Euros/tonne) over
project lifecycle
• ZEP produced a comprehensive review of CCS costs
including storage
• http://www.zeroemissionsplatform.eu
• Compared to capture engineering: storage costs may be
relatively low, but storage is the most uncertain part of
the CCS chain and can be the longest to prove for an
investment decision……..
• CAPTURE IS MORE EXPENSIVE BUT STORAGE LESS
CERTAIN
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16. Public Outreach
• Early engagement with
stakeholders is crucial
• Local opposition can
stop projects e.g.
Netherlands
• Community outreach is
stipulated in emerging
best practices and
standards
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