1. Permeability characterization and
alteration due to reactive transport
Hang Deng
Department of Civil and Environmental Engineering
Princeton University
For PECS
March 13th, 2012
1

2. Backgrounds for CCS
Geological storage
• Easy accessibility
• Large storage capacity Carbon Capture
(IPCC SRCCS, 2005) and Sequestration
Challenges (CCS)
• Leakage
• Proper legal
framework (property
rights etc.)
• Public acceptance
•...
(IPCC SRCCS, 2005)
(Socolow and Pacala, 2005)

3. Backgrounds for CCS
(IPCC, 2005)

4. Backgrounds for CCS
Leakage Risk
? ?
Injection stops
Time
Leakage risk due to Mineral dissolution may Geochemical-induced
pressure changes enlarge flow pathways over sealing may reduce leakage
time risk (From Prof. Catherine A. Peters)

5. CCS in China
• Willingness
• C Capture
• Subsurface environments
– Deep saline aquifers - 160~1451 Gt
– Depleted oil and gas reservoirs -
4.1~30.5 Gt
– Coal beds - 12.1~48.4 Gt
• Technologies
– Gaobeidian Project & Shidongkou
Project
– EOR (enhanced oil recovery) - Liaohe
oil field
– IGCC
(Li et al., 2009)

6. CCS in China
• Opportunities v.s. Challenges
(Seligsohn et al., 2010)

7. Motivations for me to study CCS
• Opportunities v.s. Challenges
‘COAL-POWER CONFLICT’

8. Some useful concepts
Porosity v.s. Permeability
Aquifer (reservoir) v.s. Aquitard (caprock)
Rock types, and minerals
• Igneous Rocks (Crystalline, low porosity, low permeability, fractures)
e.g. Basalt
• Metamorphic Rocks (Crystalline, low porosity, low permeability,
fractures)
e.g. Marble
• Sedimentary Rocks (high porosity, high permeability, few fractures)
e.g. Limestone (carbonates)
Sandstone (quartz)
Shale (clay minerals)

9. Some useful concepts
Porosity v.s. Permeability
Aquifer (reservoir) v.s. Aquitard (caprock)
Rock types, and minerals
Brine Chemistry
(Gherardi et al., 2007)

10. Some useful concepts
Geothermal gradient, hydrostatic pressure,
CO2 dissolution and pH
Temperature [C] Pressure [bar] CO2 solubility [mol/kgw] pH
20 30 40 50 60 70 0 50 100 150 200 0 0.5 1 2 3 4 5 6
0 0 0 0
Surface temperature Surface pressure
20 C 1 bar
200 Geothermal gradient 200 Pressure gradient 200 200
25 C/km 100 bar/km
400 400 400 400
600 600 600 600
800 800 800 800
Depth [m]
1000 1000 1000 1000
1200 1200 1200 1200
1400 1400 1400 1400
1600 1600 1600 1600
1800 1800 1800 1800
2000 2000 2000 2000

11. Some useful concepts
Relevant chemical reactions
Carbonic acid formation CO2 + H2O  HCO3- + H+
Reactions with aluminosilicates – slow
Mg5Al2Si3O10(OH)8 + 5 CO2  5 MgCO3 + H4SiO4 + Al2Si2O5(OH)4
Reactions with carbonates and sulfates – fast
CaCO3 + H2O + CO2(aq)  Ca2+ + 2 HCO3-
Reactions with cements
CaO SiO2H2O + CO2  CaCO3 + SiO2H2O
Ca(OH)2 + CO2  CaCO3 + H2O
Fractures: mechanical v.s. hydraulic
aperture

12. Overview of past, present and future research
Hydrogeological characterization of Ottawa
County, Michigan
Impacts of microfracture network
geometry on permeability
Reactive transport in fractured rock and its
impact on permeability

13. Overview of past, present and future research
Shales and mudstones
(caprock above Viking formation – Alberta)
(Image sources: Prof. Peters) (Image sources: Ellis et al., 2011)
13

14. 1.Hydrogeological characterization
—— target formation
Target formation: Mount Simon Sandstone (Cambrian)
• Medium to coarse quartz sandstone, high porosity (12.89 ± 0.05%, Barnes et
al., 2009) and permeability (2.0687 ± 2.448 logmd, Barnes et al., 2009)
• Overlain by Eau Claire, relatively non-permeable (5.9 ± 0.06%, − 2.22 ± 1.16
logmd, Barnes et al., 2009)
• High Capacity (Michigan State >600,000 MM tons, Medina et al., 2010)
(source: Medina et al., 2010)

15. 1.Hydrogeological characterization
—— potential injection site
Potential site: Ottawa County, Michigan
• Depth: about 1900m
• Porosity (13.4%) & Permeability (238 md)
•Thickness: around 250m
Ottawa County
(Image source: Medina et al., 2010)

16. 1.Hydrogeological characterization
—— summary permeability
Permeability k (mD)
10-8 10-6 10-4 10-2 100 102 104 5×105
Depth (m)
0
Geophysical
well logs
(gamma,
neutron,
density and
resistivity
conductivity)
from 22
wells in
Ottawa
County
(DNRE)
+
Mineralogical data
2170.8
K–C
K–T 16

17. 1.Hydrogeological characterization
—— summary permeability
• Large variability within one
Probability plot for Lognormal V.S. GEV distribution, MNSM
Probability plot for lognormal V.S. GEV distribution, MNSM
formation, largely accounted for by
0.95 Lognormal vertical variability.
0.95
0.9 Data Points
0.9
GEV
0.75
0.75 • Both Lognormal and Generalized
Extreme Value (GEV) distributions
0.5
0.5 pass Kolmogorov-Smirnov test
(α=0.01), and GEV captures
0.25
0.25 permeability at the two tails better.
0.1
0.1
0.05
0.05 • Sampling from the distribution
5
105
Permeability k (mD)

18. 2.The impacts of microfractures on permeability
——backgrounds
Shales and mudstones
(caprock above Viking formation – Alberta) Graphic source: Smith et
Image source: Prof. Peters al. Int. J. Greenhouse Gas
Control 5 (2011) 226–240

19. 2.Impacts of microfracture network on
permeability
Z
Shales and mudstones
(caprock above Viking formation – Alberta) X
(Image sources: Prof. Peters) -8
-9
-10
Flow direction
• Impacts of geometrical properties of
Log k22 (log m2)
-11
microfracture network on permeability
-12
ai -13
e.g. Aperture li -14
Roughness -15
-16
-17
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Roughness  / am 19

20. 3.Reactive transport in a single fracture
Shales and mudstones
(caprock above Viking formation – Alberta)
(Image sources: Prof. Peters) (Image sources: Ellis et al., 2011)
20

21. 3.Reactive transport in a single fracture
—— Motivation and backgrounds
Q: What are the impacts of mineralogy and brine chemistry on
integrity of fractured caprocks?
• Often neglected at large-scale simulations
Fractured Caprock (Gherardi et al., 2007)
• High reactivity in the case of CO2 storage
Sealed Caprock (Gherardi et al., 2007)
0.95 3.17
 Forcing reactions out of equilibrium
CO2 solubility [mol/L]
Caprock • Carbonates and sulfates (e.g.
layer 1 calcite, dolomites)
(0.001m) • Silicates (e.g. anorthite)
pH
• Cements
0.9 3.16
 Enhancing reaction rate
• Calcite: CaCO3 Ca2+ + CO32-
0.85 3.15
100 105 110 115 120 125 130 135 140 145 150
PCO2 [bar] Caprock
Sealing after
layer 2
6.6 yr (0.003m)
21

22. 3.Reactive transport in a single fracture
—— Motivation and backgrounds
Q: What are the impacts of mineralogy and brine chemistry on
integrity of fractured caprocks?
• Natural and induced fractures
Fractured Caprock (Gherardi et al., 2007)
• Generally, fast flow rate and high reactivity
Sealed Caprock (Gherardi et al., 2007)
Caprock
layer 1
(0.001m)
Sealing after Caprock
layer 2
6.6 yr (0.003m)
22

23. 3.Reactive transport in a single fracture
—— Motivation and backgrounds
Precipitation/dissolution pattern in a fracture depends on:
High Da Low Da ∆a
Transport-controlled Reaction rate-controlled
Mineralogy
Reaction Rate
Brine Chemistry
Fracture Geometry Flow Rate
Confining Pressure
t = 7 hr (Detwiler 2008)
23

24. 3.Reactive transport in a single fracture
—— Approaching from two ends
Numerical tools (CFD &
Reactive transport) to
inform the experiments
Building the
experimental
set-up!!!

25. 3.Reactive transport in a single fracture
—— 1D transport
Aperture/change of aperture (µm)
500 500 500
Before After
450 Change
450
400
400 400
300
Flow direction
350 350
3.8cm
200
300 300
250 250 100
200 200
0
150 150
-100
100 100
-200
50 50
2.54cm
0 0 -300
Standard deviation of aperture ( ) is
a measure of aperture roughness.
The last term in the equation corrects
for the tortuosity due to contact area.
25

26. 3.Reactive transport in a single fracture
—— 2D transport
Aperture/change of aperture (µm)
500 500 500
Before After
450 Change
450
400
400 400
300
Flow direction
350 350
3.8cm
200
300 300
250 250 100
200 200
0
150 150
-100
100 100
-200
50 50
2.54cm
0 0 -300
0.22
Before After
5.0 5.0
0.2
0.18
1 1
Flow direction
Velocity (m/s)
0.16
5.1 5.1
0.14
2D steady state (James and 0.12
Chrysikopoulos, 2000)
2 2
0.1
5.2
5.2 0.08
0.06
3 3
0.04
5.3 0.02
5.3
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27. 3.Reactive transport in a single fracture
—— 3D CFD
y
x
Flow Rate
z
Transverse roughness Scenario 1 Transverse roughness Scenario 2
y y
a b a b
x x
-5
-5 x 10
x 10 1.25
1.14
1.2
hydraulic aperture (m)
1.12
hydraulic aperture (m)
1.1
1.15
1.08
1.06
1.1
1.04
1.02 1.05
1
1
0.98
0.96
1 4/5 3/7 1/4
1 4/5 3/7 1/4
27
a/b a/b

28. 3.Reactive transport in a single fracture
—— 3D CFD
Amount of mineral dissolution (-) / precipitation (+)
z z
-1200
-1000
-800
-600
-400
-200
200
0
1
2
3
4
y y
5
Grids
35
Percentage hydraulic aperture increase
6
30
25
7
20
Calcite
Dolomite 15
8
10
5
9
100000s
0
0 2 4 6 8 10 12 14 16 18 20
Percentage volume increase
10

29. Thank you!
Comments?
Questions!
29