CO2 geological storage Methodologies, capacity and options

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CO2 geological storage Methodologies,
capacity and options

• Dr Yves-Michel Le Nindre - BRGM

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Storage is the necessary complement to other
mitigation efforts, but

• If technological solutions exist for capture and
  transport, storage is facing to the geological
  uncertainty
• Solutions and performances vary
• And industrial constraints differ

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A number of projects have proved the feasibility
of geological storage
EU world class projects
StraCO2
National projects
Example from BRGM involvement
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Conditions of storage must guarantee efficiency
and safety for centuries

• Understanding phenomena
• Selection of proper sites
• Predictive modelling
• Monitoring, Measure and Verification
• Risk assessment and mitigation
• Regulations and standards

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From regional exploration to industrial storage
The type of storage EOR, aquifer, coal seam,
must match the CO2 flux from the emission source
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General workflow
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Two philosophies of sink and sources matching
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First step - Mapping major CO2 emission
pointsand storage opportunities (EU GeoCapacity
project)
WP 1.2 GIS mapping of new inputs and of existing
data
WP 1.3 EU maps of emission and geological storage
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Storage in aquifers Permian Rotliegend(EU
GESTCO project)

• Example of extensive aquifer in northern Europe
• Extent and facies of the Permian Rotliegend from
  UK to Polish Basin
• Neighbouring major CO2 emitters

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Storage in HC fields and coal seams
Geocapacity in hydrocarbon structures and EOR
potential
Geocapacity in coal beds and ECBM potential
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Capacity calculations

• Raw calculation of reservoir capacity
• area mean thickness mean porosity CO2
  density _at_reservoir conditions
• Use geological model
• Define reservoir geometry
• Map spatial distribution of properties (K, f)
• Apply calculation to each mesh/block and
  integrate spatially
• Capacity of HC fields
• Vol. OOIP (or gas) FVF (Formation volume
  factor) CO2 density _at_reservoir conditions
• Field is considered as depleted

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Generic modellingexercise
Fmax 32

• Assuming a reservoir with variable properties
• Example of cut off on porosity
• Porosity gt16

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Towards a more realistic capacityapplying
coefficients

• Applying cut off on porosity AND permeability
  focus on the most promising volume
• Storage efficiency
• Used space / available space
• Limitations by depth, traps, permeability,
  injectivity etc.
• Sweep efficiency
• Sweep water to replace it by CO2 depends on K,
  vol, and boundary conditions, water and sediment
  compressibility, CO2 dissolution
• Sweep HC towards production well to replace it by
  CO2

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Capacity estimation - confidence in storage
capacity

• The practical storage capacity estimate decreases
  with the number of data and the degree of
  knowledge.

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Second step site selection
Capacity (tm) A.D.f.hst.?CO2
Site selection criteria
Injectivity (kg/s/b) Q/?P
No use conflict Depth (gt800m, max) Capacity
(min) Injectivity Lithology Onshore/offshore Trap
? Seal integrity Distance/barriers from source
Sites selection
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Depth constraint

• Critical temperature 31 C
• Critical pressure 73,83 bar
• Average temp. gradient 25C / km
• Average hydrostatic pressure gradient 100 bar /
  km
• Average depth for CO2 supercritical state 800 m

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Injectivity is a limiting factor
Injectivity (kg/s/b) Q/?P

• Therefore the injection rate depends on the
  maximum pressure allowed to keep the reservoir
  and seal integrity (e.g. 20 bars) and of the
  pressure build up when injecting
• Reservoir simulations enable to estimate these
  boundary conditions.

• Injectivity is the mass of supercritical CO2
  injected by unit of time for a defined pressure
  increase
• It depends on the permeability (K) and of the
  volume of the reservoir

• Lower injectivity values need additional
  injection wells and cost

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Injection and reaction simulationafter 1000
years dissolution is the main process
Concentration of supercritical CO2 in the
reservoir
Injection point
Amount of dissolved CO2 in the water (mass
fraction) Note that brine with dissolved CO2
migrates downward as it is approximately 10 kg/m3
denser than brine without CO2.
Audigane et al., 2006
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Sleipner case ideal but not usual

• In Sleipner, Statoil injects CO2 since 1996 in a
  very high porosity, high permeability extensive
  sandy aquifer.
• It is not obvious to find a second Sleipner
  near major steel plants

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Spatial analyse Source sink matching

• Select source(s), sink(s)
• superposition of data (main emitters, capacity of
  storage, geology, fault, urban area, )
• Calculate the optimal transport route and
  distance between sources and sinks
• Distance cost
• Build a network of pipeline ?
• Land use going through an urban area or a
  national park, crossing a big river
• Obtain a GIS-based calculation tool with an
  economic evaluation

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Main steps of a storage project
Knowledge of the site - Confidence in the
long-term evolution
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Options, concerns and economy

• Options
• Producing CH4 (and store CO2) gt ECBM
• Producing incremental HC (and store 1MT/y CO2) gt
  EOR, EGR
• Store large amounts / flux of CO2 (5-10Mt/y) gt
  aquifers
• Concerns
• ECBM gt Stacking pattern, petrography and
  properties of coal seams, low capacity, needs
  upstream research field experiment
• EOR gt Constraints of flux and volume related to
  HC production
• Aquifers gt poor geological knowledge compared to
  HC fields, injectivity ?
• All gt routes
• Economy
• ECBM and EOR gt Direct valorisation of CO2 cost by
  HC
• Aquifers gt Avoiding CO2atm and taxes, needed by
  high flux plants, can be combined with HC
  production (various scenarios)

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Some constraints
Conflicts of use permitting
Reservoir properties
Costs
Seal properties
Geological knowledge
Depth
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Thank you for your attention !

• Keep in mind this diagram !