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Geologic Storage of CO2: Leakage Pathways and Environmental RisksMichael A. Celia, Catherine A. Peters, andStefan Bachu
Princeton University
andAlberta Geological Survey
May 2002
CO2 Injection and Trapping Mechanisms
Precipitated Carbonate Minerals
~800 mConfining Layer(s)
Injection Well
SupercriticalCO2
Dissolved CO2
Stratigraphic Trapping
Solubility Trapping
Mineral Trapping
Hydrodynamic Trapping
Research Questions
• How effective are the various trapping mechanisms?
• What is the likelihood and magnitude of CO2 leakage?
• What are the environmental impacts of CO2 leakage?
• Today: Solubility trapping
• Today: Abandoned wells
• Today: Mammoth Mtn, and groundwater quality
Simulation of Injection of Supercritical CO2
• TOUGH2 Simulator• Radial symmetry• Isothermal
conditions
• Confining layer permeability of 0.1 mD
• Target formation porosity 10% and permeability of 100 mD.
50 m
10 m
790 m
CO2
Brine
CO2 injection= 20 kg/s
Simulation of Injection of Supercritical CO2
After 4 years of CO2 injection
CO2 injection combined with injection of brine above the confining layer
Radial distance [m]
De
pth
[m
]
Mass of CO2/Volume [kg/m3]
Qbrine = 40 kg/s
Radial distance [m]
De
pth
[m
]
Mass of CO2/Volume [kg/m3]
Simulation of Injection of CO2
Dissolved in Water
• After 1 year • After 50 years
seal
Total Mass CO2 injected = 3.1x107 kg
seal
Total Mass CO2 injected = 1.2x109 kg
Mass of CO2/Volume [kg/m3] Mass of CO2/Volume [kg/m3]
Leakage Pathways and
Trapping Mechanisms
Injected Carbon Dioxide
SurfaceEcosystems
Confining Layer(s)
Atmosphere
lateral migration
Localized vertical migration
fractures,faults, wells
Potable Water
Leakage Pathways:Abandoned Wells in the Alberta Basin
0500100015002000250030003500400045005000
1883
1908
1917
1926
1935
1944
1953
1962
1971
1980
1989
1998
year abandoned
num
ber
of w
ells
Simulation of leakage through a single abandoned well
• Permeability of a typical well cement ~ 10-17 m2
• Permeability of a medium sand ~ 10-10 m2
De
pth
[m
]
Rate of CO2 Leakage [kg/s]
0
1
2
3
4
1.00E-17 1.00E-15 1.00E-13 1.00E-11 1.00E-09
Permeability [m^2]
Potential Effect on GW Quality
-50 50 150 250
distance, m
2 yr.
4 yr.
6 yr.
8 yr.
10 yr.
groundwater flow
CO2 leakage
deep brine aquifer
drinking-water aquifer
0.0E+00
3.0E-08
6.0E-08
9.0E-08
1.2E-07
Pb2
+ co
nce
ntr
atio
n, m
ol/L
• On the Long Valley Caldera in eastern California
• Soil gas surveys revealed CO2 concentrations as high as 95%. (CO2 concentrations > 10% toxic to humans.)
Mammoth Mountain
Changes in Metal Uptake in Plants
Elevated soil CO2 Ca1989
Zn
Mn
c b
2001
Ambient soil CO2
Mn
Zn
Ca
1989 2001
Acknowledgements
• Funding from BP and Ford.
• Equations of State: R. Bruant
• TOUGH2 Simulations: A. Guswa, S. Gasda
• Leakage Estimates: A. Duguid
• Groundwater Simulations: P. Jaffe, S. Wang
• Mammoth Mountain: S. Myneni, S.J. White