Permeability characterization and

alteration due to reactive transport

Hang Deng

Department of Civil and Environmental Engineering

Princeton University

For PECS

March 13th, 2012

1

Backgrounds for CCS

Geological storage • Easy accessibility • Large storage capacity (IPCC SRCCS, 2005)

Carbon Capture and Sequestration

(CCS) Challenges • Leakage • Proper legal framework (property rights etc.) • Public acceptance • . . . (IPCC SRCCS, 2005)

(Socolow and Pacala, 2005)

Backgrounds for CCS

(IPCC, 2005)

Backgrounds for CCS

? ? Leak

age

Ris

k

Time Injection stops

Geochemical-induced sealing may reduce leakage risk

Mineral dissolution may enlarge flow pathways over time

Leakage risk due to pressure changes

(From Prof. Catherine A. Peters)

(Li et al., 2009)

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

(Seligsohn et al., 2010)

• Opportunities v.s. Challenges

CCS in China

Motivations for me to study CCS

• Opportunities v.s. Challenges

‘COAL-POWER CONFLICT’

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)

Some useful concepts

Porosity v.s. Permeability

Aquifer (reservoir) v.s. Aquitard (caprock)

Rock types, and minerals

Some useful concepts

Brine Chemistry

(Gherardi et al., 2007)

Some useful concepts

Geothermal gradient, hydrostatic pressure, CO2 dissolution and pH

20 30 40 50 60 700

200

400

600

800

1000

1200

1400

1600

1800

2000

Temperature [C]

De

pth

[m

]

0 50 100 150 2000

200

400

600

800

1000

1200

1400

1600

1800

2000

Pressure [bar]0 0.5 1

0

200

400

600

800

1000

1200

1400

1600

1800

2000

CO2 solubility [mol/kgw]

2 3 4 5 60

200

400

600

800

1000

1200

1400

1600

1800

2000

pH

Surface temperature

20 C

Geothermal gradient

25 C/km

Surface pressure

1 bar

Pressure gradient

100 bar/km

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

Hydrogeological characterization of Ottawa County, Michigan

Impacts of microfracture network geometry on permeability

Reactive transport in fractured rock and its impact on permeability

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

Overview of past, present and future research

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)

Potential site: Ottawa County, Michigan • Depth: about 1900m • Porosity (13.4%) & Permeability (238 md) •Thickness: around 250m

1.Hydrogeological characterization

—— potential injection site

(Image source: Medina et al., 2010)

Ottawa County

16

1.Hydrogeological characterization

—— summary permeability

10-8 102 10-6 10-4 100 10-2 104 5×105

K – C K – T

Permeability k (mD)

Depth (m) 0

2170.8 + Mineralogical data

Geophysical well logs (gamma, neutron,

density and resistivity \

conductivity) from 22 wells in Ottawa County (DNRE)

• Sampling from the distribution

• Both Lognormal and Generalized Extreme Value (GEV) distributions pass Kolmogorov-Smirnov test (α=0.01), and GEV captures permeability at the two tails better.

• Large variability within one formation, largely accounted for by vertical variability.

105

0.05

0.1

0.25

0.5

0.75

0.9

0.95

Lognormal

Data Points

GEV

Probability plot for Lognormal V.S. GEV distribution, MNSMProbability plot for lognormal V.S. GEV distribution, MNSM

105

0.9

0.75

0.95

0.25

0.5

0.1

0.05

Permeability k (mD)

1.Hydrogeological characterization

—— summary permeability

2.The impacts of microfractures on permeability

——backgrounds

Shales and mudstones

(caprock above Viking formation – Alberta)

Image source: Prof. Peters Graphic source: Smith et al. Int. J. Greenhouse Gas Control 5 (2011) 226–240

• Impacts of geometrical properties of microfracture network on permeability

e.g. Aperture Roughness

X

Z

Shales and mudstones

(caprock above Viking formation – Alberta)

(Image sources: Prof. Peters)

ai

li

Flo

w d

irectio

n

2.Impacts of microfracture network on

permeability

19 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

-17

-16

-15

-14

-13

-12

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-9

-8

Roughness / am

Lo

g k

22 (

log

m2)

Shales and mudstones

(caprock above Viking formation – Alberta)

(Image sources: Prof. Peters) (Image sources: Ellis et al., 2011)

20

3.Reactive transport in a single fracture

Q: What are the impacts of mineralogy and brine chemistry on

integrity of fractured caprocks?

• Often neglected at large-scale simulations

• High reactivity in the case of CO2 storage

0.85

0.9

0.95

100 105 110 115 120 125 130 135 140 145 1503.15

3.16

3.17

PCO2 [bar]

CO

2 s

olu

bili

ty [

mo

l/L]

pH

Forcing reactions out of equilibrium • Carbonates and sulfates (e.g. calcite, dolomites) • Silicates (e.g. anorthite) • Cements

Enhancing reaction rate

CaCO3 Ca2+ + CO32- • Calcite:

Fractured Caprock (Gherardi et al., 2007)

Caprock layer 1 (0.001m)

Caprock layer 2 (0.003m)

Sealed Caprock (Gherardi et al., 2007)

Sealing after 6.6 yr

21

3.Reactive transport in a single fracture

—— Motivation and backgrounds

Fractured Caprock (Gherardi et al., 2007)

Q: What are the impacts of mineralogy and brine chemistry on

integrity of fractured caprocks?

• Natural and induced fractures

• Generally, fast flow rate and high reactivity

Caprock layer 1 (0.001m)

Caprock layer 2 (0.003m)

Sealed Caprock (Gherardi et al., 2007)

Sealing after 6.6 yr

22

3.Reactive transport in a single fracture

—— Motivation and backgrounds

High Da Transport-controlled

t = 7 hr (Detwiler 2008)

Low Da Reaction rate-controlled

∆ a Precipitation/dissolution pattern in a fracture depends on:

Mineralogy

Brine Chemistry

Fracture Geometry

Reaction Rate

Flow Rate

Confining Pressure

23

3.Reactive transport in a single fracture

—— Motivation and backgrounds

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!!!

2.54cm

3.8

cm

0

50

100

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500

0

50

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Before After

-300

-200

-100

0

100

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500

Change

Ap

erture/ch

ange o

f apertu

re (µm

)

Flo

w d

irec

tio

n

25

Standard deviation of aperture ( ) is a measure of aperture roughness. The last term in the equation corrects for the tortuosity due to contact area.

3.Reactive transport in a single fracture

—— 1D transport

2.54cm

3.8

cm

0

50

100

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500

0

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Before After

-300

-200

-100

0

100

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500

Change

Ap

erture/ch

ange o

f apertu

re (µm

)

Flo

w d

irec

tio

n

0.5

1

1.5

2

2.5

3

3.5

0.5

1

1.5

2

2.5

3

3.5

Flo

w d

irec

tio

n V

elocity (m

/s)

Before After

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0.22

2D steady state (James and Chrysikopoulos, 2000)

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3.Reactive transport in a single fracture

—— 2D transport

27

y

x

a b

y

x

a b

Transverse roughness Scenario 1

x

y

z

Flow Rate

Transverse roughness Scenario 2

1/43/74/51

0.96

0.98

1

1.02

1.04

1.06

1.08

1.1

1.12

1.14

x 10-5

a/b

hyd

rau

lic a

pert

ure

(m

)

1/43/74/51

1

1.05

1.1

1.15

1.2

1.25x 10

-5

a/b

hyd

rau

lic a

pert

ure

(m

)

3.Reactive transport in a single fracture

—— 3D CFD

y

z

y

z

12

34

56

78

910

-1200

-1000

-800

-600

-400

-200 0

200

Grid

s

Amount of mineral dissolution (-) / precipitation (+)

10

00

00

s

Calcite Dolomite

0 2 4 6 8 10 12 14 16 18 20

0

5

10

15

20

25

30

35

Percentage volume increase

Pe

rce

nta

ge

hyd

rau

lic a

pe

rtu

re in

cre

ase

3.Reactive transport in a single fracture

—— 3D CFD

Thank you! Comments? Questions!

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