Geological storage of carbon dioxide in the UK
GeoCapacity Project
Karen Kirk
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Types of storage site
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Premium sites - Oil and gas fields
¾ known to contain buoyant fluids
¾ well known geologically
¾ Pressure depletion
Potentially good sites - Saline water-bearing
reservoir rocks
¾ Need to demonstrate containment
¾ Poorly known geologically
Coal seams – poor permeability in UK
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Where could we
store CO2 in the UK?
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Best potential lies
within the offshore
sedimentary basins
Onshore hydrocarbon
fields mostly too small
to consider
Onshore aquifers
either too shallow or
contain potable water
supply
Lack of closed
structures in onshore
aquifers
Offshore - Southern North Sea
Gas Fields
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Many depletion
drive reservoirs in
the Rotliegend
Leman Sandstone
Triassic and
Carboniferous
reservoirs
Up to 3900 Mt
Offshore - Southern North Sea
Saline Aquifers
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Bunter Sandstone
Formation
Many structures are
faulted to greater or
lesser degrees
Pragmatic approach regard them as
upside potential and if
accessible, test from
an existing storage
project at a gas field
Up to 14000 Mt
North and Central North Sea
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Study by ECL
2002:
1200 Mt of CO2
could be stored as
a result of EOR
GeoCapacity
study – straight
storage value:
3550 Mt
Offshore – East Irish Sea
Oil & Gas Fields
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Ormskirk Sandstone
Formation (Bunter
equiv.)
Most promising potential
within the Morecambe
fields (873 Mt)
Up to 1050 Mt
Offshore – East Irish Sea
Saline Aquifers
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Ormskirk Sandstone
Formation (Bunter
equiv.)
Downthrown fault blocks
Lie within hydrocarbon
migration pathways
Up to 630 Mt
Estimation methodology
Gas Fields
MCO2 = (VGAS (stp) / Bg) . ρCO2
Where:
MCO2 = CO2 storage capacity (106 tonnes)
Stp = standard temperature and pressure
VGAS (stp) = volume of ultimately recoverable gas at stp (109 m3)
Bg = gas expansion factor (from reservoir conditions to stp)
ρCO2 = density of CO2 at reservoir conditions (kg m-3)
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Estimation methodology
Saline Aquifers
MCO2(tonnes) = Ototal pore volume x + ρCO2 x 0.4*
*
+
O
Based on simulation of structures in the Bunter sandstone (Obdam et al.
2003), maximum CO2 saturation of the pore space that could be achieved is
approximately 40%.
Calculated from experimental equations of state (Eric Lindeberg pers
comm.)
Calculated using the gross rock volume (thickness and area), times the net
to gross where available multiplied by the average porosity.
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Estimation methodology
Oil Fields
MCO2 = (VOIL (stp).Bo) . ρCO2
Where:
MCO2 = CO2 storage capacity (106 tonnes)
stp = standard temperature and pressure
VOIL (stp) = volume of ultimately recoverable oil at stp (109 m3)
Bo = oil formation volume factor
ρCO2 = density of CO2 at reservoir conditions (kg m-3). (Span & Wagner
1996).
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Summary
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UK well endowed with storage capacity but this is
essentially all offshore
Potential storage in oil fields, gas fields and aquifers
Best understood potential within in oil and gas fields
Aquifers need further investigation to be considered
Potential for EOR if the window of opportunity is not
missed
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Summary
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Oil fields:
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SNS gas fields:
EISB gas fields:
Condensate fields:
SNS Bunter Sst:
EISB Ormskirk Sst:
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Total “quantified”:
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~1200 Mt CO2 from EOR
~3550 Mt
~3900 Mt
~1000 Mt??
~1200 Mt??
up to ~14000 Mt
up to ~600 Mt?
~22 to 24 gigatonnes (109 tonnes)