1

ITG

2

Herbert HuppertProcesses in the reservoir

Sleipner

3

leakage / seepage

(Bickle 2009)

Sleipner:

4

Atm

osph

eric

ca

rbon

dio

xide

in p

pm Mauna Loa Observatory

310

320

330

340

350

360

370

380

390

400

1960 1970 1980 1990 2000 2010

5

• Theory

• Laboratory experimentation

• Interpretation of field data

6

Competing phenomena

• Trappingstructural trappingcapillary (or residual) trappingdissolution trapping mineralisation

• Leakage

• Far-field brine migration

• Structural uplift

7

Fluid source in porous mediumAxisymmetric gravity currents in a porous medium (Lyle et al., JFM 543, 293 - 302)

rN t( )= ηN γQ/φ( )1 4t 1 2

rN (t)

z

r

h (r,t)

inputdensity ρ

Porous mediuminterstitial fluid density

ρ + ∆ρ

Porous mediuminterstitial fluid density

h r,t( )

8

0

1

2

3

4

5

0

2

4

6

8

10

0

1

2

3

4

0

1

2

3

1996 2000 2004 2008 1996 2000 2004 2008

Horizon 2 Horizon 5

Horizon 6 Horizon 9r2 (m2 x 105)

Sleipner Data

year year

0

1

2

3

4

0

2

4

6

8

1

2

3

10

0

1

2

3

4

5

0

9

t1

t2

t3

kkbk

Modelling flow along low permeability layers

10

Lateral extent of overriding current

11

0.97

0.98

0.99

1.00

1.01

1.02

0 20 40 60 80 100

MEG/Water mixes

Den

sity

(g/

cc)

V% MEGWater

54% MEG

51% MEG

48% MEG

Convective dissolution

MEG = methanol plus ethylene glycol

J. Neufeld, M. Hesse, A. Riaz, M. Hallworth, H. Tchelpi & HEH, GRL

12

13

14

At Sleipner

⇒ Ra = 1.4 x 104 >> 1

⇒ FCO2 = 18 kg m2 yr−1

⇒ FCO2 A ≈ 0.1 MT yr−1

k = 2.5 x 10-9 m2 ρ∆− ≈10.5 kg/m µ ≈ 4.5 x 106 Pa sH ≈ 20m

A ≈ 5.6 x 106 m2

15

x

h (x,t)

inputdensity ρ

ρ + ∆ρ

bW

k

x

inputdensity ρ

ρ + ∆ρ

bW

kh (x,t)

Leakage(Neufeld, Vella, HEH & Lister, JFM x 3)

16

17

t

xN

xN+

xN-

Up- and downstream extent –- theory and experiment

18

∝ t−1 2 t → ∞( )i.e. asymptotically it all leaks

volume in current

volume injected= = efficiency of storageξ

t

ξ

ελ = 0

19

ξ

t (days)

Using parameters relevant to Sleipner

20

2-D

point source & sink

point source/line sink

ξ → t−1 2

ξ → 1 lnt

ξ → t−2 5

21

Leakage from a slope P. Zimoch, J. Neufeld & D. Vella, JFM

22

23

24

25

ξ

t

Efficiency for storage on a slope, theory and experiment

26

• anisotropic heterogeneous permeability

• chemical reactions with hot rock

• convection (thermal and/or volatile/dissolution driven)

• possible dissolution leading to changes in viscosity and density

• mineralisation

Additional effects

27

Costs

~ 2% GDP

~ 1 year’s growth

20 - 100% extra per unitfor capture, transport and storage

28

US Sequestration Opportunities

Billion Metric Tons of CO 2

Billion Tons of CO2

Billion Metric Tons of CO 2

Billion Tons of CO2

BIG SKY 271 299 1,085 1,196MGSC 29 32 115 127MRCSP 47 52 189 208PCOR 97 107 97 107SECARB 360 397 1,440 1,587SOUTHWEST 18 20 64 71WESTCARB 76 84 304 335

Total 898 991 3,294 3,631

CO2 Capacity Estimates by PartnershipDeep Saline Formations

Low High

Field Studies

29

Current sequestration projects

AII

CCP2

MGSC

Mountaineer

PCORMRSCP

Frio

Weyburn II

Gorgon

Otway

Callide

COACHLacq

InSalahHassi Touareg

Karniow

KetzinSleipner

30

• Fluid mechanics can help quantitatively in the interpretation of carbon dioxide injection and spreading

• Simple models for flow in one layer describe aspects of the evolution at Sleipner

• Convective dissolution of carbon dioxide into the surrounding brine can be quantified

• Leakage through a fracture could be substantial

Conclusions

31

ITG

32

BEM/MRM 37, September 2014, New Forest, UK

Interfacial ProcessModelling

University of Nottingham

33

•

Viscous Fingering

β = 70β = 2

Images from: http://www.petrowiki.org

34

CO2 Injection

A temperature distribution resulting from the temperature difference between the injected CO2 and resident brine can result in a significant rate of evaporation from the brine, that can affect the evolution of the fingers.

Finger break

35

� Surface tension depends on temperature

� CO2 is injected at a different temperature that the ambient brine

� If surface tension were to vary along an interface, there would be an imbalance of forces which in turn would cause flow, modifying the CO2 plume evolution

Marangoni effect

36

Results – Comparison

37

Dissolution-driven convection of a reactive solute

Ra : Rayleigh number, giving the relative

importance of buoyancy forces to solute

diffusivity,

Da : Damköhler number, giving the rate

of reaction compared to the rate of

solute transport by the flow,

Sh: dimensionless flux of solute into the

cell.

C : dimensionless solute

concentration,

Ψ : dimensionless stream function,

38

Effect of chemical reaction on the time-averaged flux of solute

Time-averaged flux for increasing rates of reaction

Time- and horizontally-averaged concentration profiles