Quantifying CO2 Massin Subsurface from Seismic Data
地震波探査データに基づく
CO2貯留量評価技術の開発
Ziqiu Xue
薛 自求
xue@rite.or.jp
Research Institute of Innovative Technology for the Earth (RITE)

CO2 Stored in Saline Aquifer

Juanes et al., 2006

Geological Sequestration of CO2

Objectives of CO2 Monitoring
Map the movement of CO2 & CO2 isbeing safely contained in reservoir.
CO2 sequestration is a safe andverifiable mitigation technology option
Monitoring, Measurement and Verification : MMV
Monitoring, Evaluation, Reporting and Verification : MERVExamples from CO2-EOR &CO2 storage projects
Cross Well Seismic and Electromagnetic (EM)•McElroy oil field, West Texas, USA (Harris et al.,1995)•Lost Hills oil field, South California, USA (Hoversten et al.,2003)

Time-lapse 3D Seismic Survey (4D Seismic)•Weyburn oil field, South Saskatchewan, Canada (White,2004)•Sleipner, aquifer, North Sea, Norway (Art et al., 2004)

Pre-CO2
Gas CO2

Liq. CO2

S.C. CO2

Post-CO2-10.7(%)-11.1(%)-16.4(%)

s)
Xue et al., (2009)

Seismic records with identifiable P and S

P-phaseS-phaseSeismic response to CO2 replacing
water in porous Tako sandstoneImaging CO2 in the reservoir @Sleipner
vertical section

plan view

Chadwick (2009)CO2 Mass Estimation with Seismic Data
@Sleipner (Arts et al., 2002)

White (2004)

Estimated CO2 Mass>98% in reservoir

Biot – Gassmann - Domenico Theory
Two phase (partial saturation)Vp 4 K   G
3 Vs 2G Kd 
1 Ks 
K  Kd  1    K d
 2Kf
KsKs

Swφρρsρw
ρcKKdKsKwKc
KfGGd

Water saturation---Rock porosity---Material density

kg/m

Solid framework density

kg/mwater bulk density

kg/m

CO2 bulk density
Bulk modulus

kg/m
GPa

Dry rock bulk modulus

GPa

Solid framework bulk modulus

GPa

Water bulk modulus

GPa

CO2 bulk modulus

GPa

Pore fluid bulk modulus

GPashear modulus

GPa

Rock shear modulus

GPa

3333

Geophysical Parameters
wave velocity, resistivity
Inversion
problemRock Physics Model

uncertainty

Reservoir Parameters
fluid, gas saturation

Sonic Vp vs CO2 Saturation@ Nagaoka

During CO2 injection
Post-CO2 injection

Sonic Vp and resistivity vs CO2 saturation
3.06.5

2.5

6.0

Vp
2.05.5

1.55.0 (ohm-m)

Vp (km/sec)(1116.0m @ OB-2, Nagaoka)

ρ1.04.5
0.0

0.20.4CO2 Saturation

0.60.8(16/25)
Mito and Xue(2009)

Estimating CO2 Saturation from Induction Log Data
(1116.0m @ OB-2, Nagaoka)

Nakatsuka et al. (2010)

Suggested Eq.1 and Eq.2
RI: Resistivity Index

Results of estimated CO2 saturation
with suggested Eq.1 and Eq.2

Nakatsuka et al. (2010)

CO2 Derived from Induction Log @Nagaoka1108(%)

Depth (mMD)

Post injection

30252015
1050-5-101112

Mobile CO21116

Dissolved CO21120
0500

1000
1500
2000
Elapsed time (day)2500

White (2004)

3D flow simulation of topmost layer growth by 2006

depth contours

3 Darcy

3 Darcy E-W
10 Darcy N-S

3/10 Darcy (higher temp)

Core testing 2 - 3 Darcy
Well testing 1 - 8 Darcy

Chadwick (2009)
Model 3 Darcy

Methodology

TOUGH2(22/26)

Breakthrough Time Matching
OB-4Formation dip: 15°Injection Well

60m Observation well
40m

120m

IW-1

OB-2OB-3Good Match!

Velocity Anomaly Matching

Conclusion• P- and S-wave clearly response to CO2
injection into porous sandstones and strongly
support monitoring and quantification of CO2
mass stored in reservoir.
• Joint inversion of seismic wave velocity andresistivity is helpful for improving
understanding and modeling on CO2 migrationin subsurface.
• History matching results from CO2 flow
simulation and monitoring provides insights toquantifying mass of CO2 injected in reservoir.

Acknowledgements• This project is funded by Ministry ofEconomy, Trade and Industry (METI) ofJapan.
• We thank staff of ENAA, INPEX Co.,
Geophysical Surveying Co. Ltd., OYO Co.,GERD and RITE involved in Nagaoka pilot
CO2 injection project.