Seismic Velocity and Resistivity Changes during CO2 Injection into … · 2012. 4. 5. · International Workshop on CO2Geological Storage , Japan ‘06 Laboratory Study and Field

International Workshop on CO２ Geological Storage , Japan ‘06

Seismic Velocity and Resistivity Changes during Seismic Velocity and Resistivity Changes during COCO22 Injection into WaterInjection into Water--saturated Sandstonessaturated Sandstones

Ziqiu Xue

[email protected]

Research Institute of Innovative Technology for the Earth

Application of Rock Physics to CO2 Monitoring in Geological Sequestration


Monitoring of Injected CO2

• Map the movement of CO2 & the CO2 is being safely contained within the reservoir.

• Injection of CO2 Causes Wave Velocity to Decrease and the Pore Pressure to Increase .

• Lab Experiments are required to Convert Field Results of Wave Velocity to CO2 Saturation.


Laboratory Study and Field Survey Laboratory Study and Field Survey in COin CO22 Geological SequestrationGeological Sequestration

FieldField--scalescale

•4D Seismic Survey

•Crosswell Tomography

•Well Logging (sonic, induction, neutron)

LLab-scale•Wave Velocity and Resistivity

changes during CO2 injection

•Sandstones with different porosityporosityand permeabilitypermeability

•Drilled Cores from CO2 injection sites

Geophysical ParameterGeophysical Parametervelocity, resistivityvelocity, resistivity

Reservoir ParameterReservoir Parameterfluid saturationfluid saturation



Wave Velocity ResponseWave Velocity Response

due to

COCO22 Injection in Tako SandstoneInjection in Tako Sandstone



P-wave forms obtained from pre- and post- CO2 flooding in Tako sandstone.

-0.10

-0.05

0.00

0.05

0.10

10 15 20 25 30

P-w

ave

Am

plit

ude

(V)

Gross Travel Time (microseconds)

post-CO2pre-CO2

Vp: -10%

Supercritical COSupercritical CO22



Experimental setup for P-wave velocity tomography

Syringe pump #1 for oilhydrostatic pressure

#2 for pore waterpore pressure

#3 for CO2injection pressure

Array: 8 x 8

D=5, L=10cm



1

54

8

23

76

9

1312

16

1110

1514

BTM

TOP

Experimental Study of Seismic Wave Tomography

H2O/CO2 Sandstone: 23%, 3md



CO2 migration in water-saturated sandstone

Pore space (blue resin)

CO2 flows parallel to bedding plane; Numeric numbers: Elapsed time

CO2 Xue and Lei, 2006



S1 R1

S4

S3

S6

R4

R6

Velocity Reduction vs Pore Space



-10.7(%)

-11.1(%)

-16.4(%)

Gas CO2

Liq. CO2

S.C. CO2

(µs)

Ray path: S1-R1

Pre-CO2 Post-CO2


10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

TS-5(S3-R6) .dat

-5.1(%)

-7.4(%)

-8.5(%)

Gas CO2

liq. CO2

s.c. CO2

(µs)

Ray path: S3-R6


Estimation of Estimation of COCO22 Saturation Saturation

from

Sonic PSonic P--wave Velocity wave Velocity



CO2 saturation?

Velocity reduction: Velocity reduction: --23%23%International Workshop on CO２ Geological Storage , Japan ‘06


1145.49m - 1145.58m

finefine--grain sandstonegrain sandstonediameter: 5cm，length: 7cm

Observation Well OB-2



Experimental System Diagram

Measurements of Vp during injection of CO2under simulated in-situ P&T conditions.

Flow

Supercritical CO2

Pore Water


0.0

0.5

1.0

1.5

2.0

2.5

0 20 40 60 80 100

Vel

ocit

y (k

m/s

)

Elapsed Time (min)

-100

-80

-60

-40

-20

0

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80 100

Vel

ocit

y R

educ

tion

(%)

Amplitude R

atio

Elapsed Time (min)

Pore Pressure ： 10 MPaCO2 Inj.Pres. ： 10.5 MPaTemperature ： 38℃

AmplitudeAmplitude

velocityvelocity（（%%））

Sonic Vp （Zone 2）

Pre-CO2: 2.3 km/s

Post-CO2: 1.8 km/s

- 21.7 %

BreakthoughBreakthough



History Matching on Sonic Vp

Velocity reduction due tobreakthrough of CO2

Estimation of CO2Saturationwith Gassmann theory

Sonic Vp in Observation Well OB-2 at Nagaoka CO2 Injection Site

Xue et al.,2006



第13回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第14回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第15回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第16回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

13th 14th 15th 16th

CO2 saturation (fraction)

Dep

th (m

)



第17回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第18回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第19回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第20回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

17th 18th 19th 20th

CO2 saturation

Dep

th (m

)



第21回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第22回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

第23回

950.00

1000.00

1050.00

1100.00

1150.00

1200.00

0.00 0.20 0.40 0.60 0.80 1.00

Sc(Uniform)

21st 22nd 23th

CO2 saturation

Dep

th (m

)



1.5

1.7

1.9

2.1

2.3

2.5

2.7

0.0 0.2 0.4 0.6 0.8 1.0

1115mP-

wav

e V

eloc

tiy (k

m/s

)

CO2 saturation

1.5

1.7

1.9

2.1

2.3

2.5

2.7

0.0 0.2 0.4 0.6 0.8 1.0

1116m

P-w

ave

Vel

ocity

(km

/s)

CO2 saturation

1.5

1.7

1.9

2.1

2.3

2.5

2.7

0.0 0.2 0.4 0.6 0.8 1.0

1117m

P-w

ave

Vel

ocity

(km

/s)

CO2 saturation

P-wave velocity vs CO2 saturation

▲： estimated from sonic Vp

: predicted with Gassmann theory



Resistivity ChangesResistivity Changes

caused by

COCO22 Injection in Berea SandstoneInjection in Berea Sandstone



Resistivity changes during injection of s.c. CO2into Berea sandstone saturated with artificial formation water

Kubota et al.,2006


CONCLUSIONSCONCLUSIONS• P-wave velocity and resistivity clearly responded

to CO2 injection into water-saturated sandstones.

Vp: -10% (order); ρ: + 300% (Max)

• CO2 migration pattern depends strongly on heterogeneous pore structure and bedding plane in porous sandstones.

• Confirmed sonic Vp reduction (-20%) due to CO2breakthrough with drilled cores retrieved from the observation well OB-2.



Conclusions (cont.)Conclusions (cont.)• Successfully applied Gassmann Theory to estimate CO2 saturation from sonic P-wave velocity.

less Vp decrease: >20% CO2 saturation

•Resistivity increases are larger in sandstone sample (lab-scale) compared to induction logging (field-scale).

•Supporting developments of costcost--effectiveeffectivemethods for CO2 monitoring in geological sequestration.



ACKNOWLEDGMENTSACKNOWLEDGMENTS

•This project is funded by Ministry of Economy, Trade and Industry (METI) of Japan.

•We thank staffs of ENAA, Teikoku Oil, OYO Co., Geophysical Surveying Co., CRIEP and RITE involved in Nagaoka pilot CO2 injection project.


Documents

Seismic Velocity and Resistivity Changes during CO2 Injection into … · 2012. 4. 5. · International Workshop on CO2Geological Storage , Japan ‘06 Laboratory Study and Field