Fourteen years’ experience of monitoring CO2
injection in the Utsira Sand at Sleipner,
offshore NorwayKyoto, 9 december 2010

Rob Arts, Andy Chadwick & Ola Eiken

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Quantitative interpretation of the data
• Match to the reservoir simulation• Synthetic seismic modeling• AVP (Amplitude vs. ray parameter) analysis• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Injection scheme at Sleipner

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Extension of the Utsira Sand
Depth

100 kmRob Arts, Andy Chadwick & Ola Eiken

Thickness

Total area of theUtsira Sand isapproximately
26.000 km2
Kyoto, 9 december 2010

Reservoir characteristics:
Log panel (W-E, 20 km)

15_8_01 [SSTVD]
SSTVD 0.00
-2.00
SSTVD 400

400

GR
ILD

15_9_07 [SSTVD]

200.00
3.00

SSTVD 0.00
-2.00
SSTVD 400

400

GRILD

15_9_08 [SSTVD]

200.00
3.00

SSTVD 0.00
-2.00
SSTVD 400

400

GRILD

15_9_18 [SSTVD]

200.003.00

SSTVD 0.00
-2.00
SSTVD 400

400

GR
ILD

15_9_16 [SSTVD]

200.00
3.00

SSTVD 0.00
-2.00
SSTVD 400

400

GR
ILD

15_9_13 [SSTVD]

15_9_A_16 [SSTVD]

200.00
3.00

SSTVD 0.00

SSTVD 400

400GR

200.00

SSTVD 0.00
-2.00
SSTVD 400

200.00
3.00

400

500

500

500

500

500

500

500

600

600

600

600

600

600

600

700

700

700

700

700

700

700

800

800

800

800

800

800

800

900

900

900

900

900

900

900

1000

1000

1000

1000

1000

1000

1000

1100

1100

1100

1100

1100

(1100)

1100(1200)

1200

1200

1200

1200

(1200)

1200(1309)(1309)(1309)(1309)(1309)(1309)

1309

Rob Arts, Andy Chadwick & Ola Eiken

GRILDKyoto, 9 december 2010

SSTVD 400

Reservoir analogue

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Synthetics of well 15/9-18

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Top Utsira

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Base Utsira

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Top Utsira around the injection point

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

The Utsira reservoir

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Injected CO2
11Accumulated mass
(million tons)

10
98
7
6

seafloor mapping
highres seismic

54

CSEM survey

3gravity surveys

2
1

seismic surveys

0
1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

DateRob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Quantitative interpretation of the data
• Match to the reservoir simulation• Synthetic seismic modeling• AVP (Amplitude vs. ray parameter) analysis• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Sleipner CO2 injection Time-lapse seismic data 1994

2001
Utsira Fm.

CO we2ll

CO2 plume in map view

2008

2008-1994

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Inline of TL-seismic surveys

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Determination of the pushdown

IL
XL

XLine 3080

3838
3083

3838
3099

3838
3115

XLine 3123

XLine 3135
XLine 3135

38383131

3838
3147

3838
3163

3838
3179

3838
3195

-800

-825

ILXL

XLine 3080

3838
3083

3838
3099

3838
3115

XLine 3123

XLine 3135
XLine 3135

3838
3131

3838
3147

3838
3163

3838
3179

3838
3195

-800

1994 data

-825

-850

-850

-875

-875

-900

-900

-925

-925

-950

-950

-975

-975

-1000

-1000

-1025

-1025

-1050

-1050

-1075

-1075

-1100

-1100

-1125

-1125

-1150

-1150

-1175

-1175

-1200

-1200

-1225

-1225

Rob Arts, Andy Chadwick & Ola Eiken

1999 data

Kyoto, 9 december 2010

Histogram of the amplitudes: Amplitudes lower
than -0.5 suggest presence of CO2

1994

Rob Arts, Andy Chadwick & Ola Eiken

2008

-0.5

Kyoto, 9 december 2010

Most important CO2 amplitude maps from 3Dsurvey

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Impression of the 2002 CO2 accumulations interpreted
from the seismic data

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Synthetic modeling of the seismic response

Thickness of127 m

Top reservoir

Bottom reservoir
Tuning effect at the top of the reservoir

TWT of123 ms

Top reservoirBottom reservoir“Push-down” effect below the CO2 accumulation

Thickness CO2 accum ulation below
the shale barriers (m )0Amplitude (blue trough)

SandCO2Shale

10200
Shale - upper CO2
column interface
Shale - middle CO2column interface
Shale - low er CO2
column interface-0.01

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

M ass of CO2 inejected

M illions

CO2 in-situ mass verification based on seismic
amplitudes
1210Mass (CO2) = ΣdZ · ρCO2 · φ · SCO2

876%
87%

690%

480%201994

101%

1996

1998

2000

2002

2004

2006

2008

2010

Yearcalculated
Rob Arts, Andy Chadwick & Ola Eiken

real injection
Kyoto, 9 december 2010

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Quantitative interpretation of the data
• Match to the reservoir simulation• Synthetic seismic modeling• AVP (Amplitude vs. ray parameter) analysis• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

High resolution seismic lines acquired in 2006

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Comparison high-res vs. 3D lines (line 6001)

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Comparison high-res vs. 3D lines (line 6008)

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Comparison high-res vs. 3D lines (line 6010)

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Comparison high-res vs. 3D lines (line 6011)

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Comparison high-res vs. 3D lines (line 16005)

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

3D interpretation and the high-res lines (line 6006)

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Interpretation of CO2 levels in 2008
The CO2 plume:•1500 m in 1999 - 4000 m in 2008
•Roughly 200 m thick•Elliptical geometry•Major levels: 05, 08 & 09

2008
9876

5
3

4212008

Rob Arts, Andy Chadwick & Ola Eiken

2008
Kyoto, 9 december 2010

Layer
09
Layer
08Layer

5 m shale layer

06/07

Layer 05-2
Layer 05

Layer 05-1

Layer 04
Layer 03

Layer 04-1

The stratighraphic pattern of thelayers in the generated model(around the CO2 plume).

Layer 02

Layer 01

The resulting reservoir simulation
model

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

History Match of the Sleipner CO2 Injection, Using 4D
Seismic Data: Base case model matched in 2008
CO 2 Mass [tonne]
0.00E+00

5.00E+05

1.00E+06

1.50E+06

2.00E+06

2.50E+06

98level654
3
21

Measured

Simulated

Base Case:
TRes=37 °C
Kv=Kh=2 Darcy
Phi=38 %Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

History Match of the Sleipner CO2 Injection, Using 4D
Seismic Data: Base case model matched in 2008
Level 01

Level 02

Level 03

Level 04

Level 05

Level 06/07

Level 08

Level 09

Comparison of the CO2 anomaly boundary observed of 4D seismic data with thebase case simulated CO2 migration pattern in 2008
Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Quantitative interpretation of the data
• Match to the reservoir simulation• Synthetic seismic modeling• AVP (Amplitude vs. ray parameter) analysis• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Layout of the (synthetic) acquisition scheme
Last cable position (shot 1)
Last shot (shot 1)

01000

2000

Rob Arts, Andy Chadwick & Ola Eiken

First cable position (shot 170)
First shot (shot 170)

3000

4000

5000

6000

7000
Kyoto, 9 december 20108000

Shot outside the CO2 plume

Shot 10Near-offset trace

Far-offset trace

TUS

BUS

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Shot over the CO2 plume
Shot 75

Near-offset trace

Far-offset trace

TUS

Effect of CO2

BUS

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Shot over the CO2 plume

Shot 95

Near-offset trace

Far-offset trace

TUS
Effect of CO2
BUS

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Stacked section (left) and migrated section (right)

TUS

TUS

BUS

BUS

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Real seismic data (1999) versus processed
seismic data-800-850-850-900-900-950

-950

-1000

-1000-1050-1050-1100-1100-1150-1150-1200-1200

3 km
Real data

Rob Arts, Andy Chadwick & Ola Eiken

SSyntheticconvolution dataN

Synthetic Finite
Difference data
after processing

Kyoto, 9 december 2010

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Quantitative interpretation of the data
• Match to the reservoir simulation• Synthetic seismic modeling• AVP (Amplitude vs. ray parameter) analysis• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Growth of top layer
Plume outline 2001

Injectionpoint

Plume outline 2006

2001

Rob Arts, Andy Chadwick & Ola Eiken

2004

Kyoto, 9 december 20102006

2008 data

2008 data set• CFP processing on top Utsira Fm• Clear reflection in plume,
weak reflection elsewhere

TopUtsira0.00040.0002p(s/km)0.0-0.0002
Rob Arts, Andy Chadwick & Ola Eiken-0.0004

Kyoto, 9 december 2010

2008 data set
AVP Top Utsira• AVP panel

Distance along inline (m)
01250

2500

0.00040.0002p(s/m)

0.0-0.0002• AVP curves• red: ‘left’ of plume• green: ‘in’ plume• blue: ‘right’ of plume• Data contain interval
0 < p < 0.0003

AVP amplitude (a.u.)
0-0.0004

no data
Rob Arts, Andy Chadwick & Ola Eiken-0.0004

ray parameters in data
0.00020p (s/m)

0.0002no data

Kyoto, 9 december 20100.0004

• Plume zone higher amplitude• Plume zone higher gradient

AVP response, Top Utsira
0reflection coefficient2008 data set
Synthetic AVP curves-0.2-0.4-0.6

PP (CO2 saturated)-0.8PP (water saturated)-100.0001

0.00020.00030.0004

AVP amplitude (a.u.)
0ray parameter p-0.0004
Rob Arts, Andy Chadwick & Ola Eiken

0.00020p (s/m)
00.00020.00040.00020.0004(p)
Kyoto, 9 december 2010

AVP curves

01994• Red: ‘left’ of plume• Green: ‘in’ plume• Blue: ‘right’ of plume

02001• Data contain interval (approx.)
4e-5 < p < 0.0003
7° < incidence angle < 45°0

• Interference from shallower reflections• Restricts validity of results to interval
0<p<0.0002 (approx.)

20040• More far offsets in more recent data sets
2006

02008 Kyoto, 9 december 2010

Rob Arts, Andy Chadwick & Ola Eikenp (s/m)-0.0004

0.000200.00020.0004

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Per station 3 gravimeters and 3 pressure gauges put ona fixed concrete benchmark

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Location of the benchmark stations visited bythe ROV

Size of CO2 bubble 2001

Gravity benchmarks

Sleipner A
Injection point

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Gravity inversion results

Sleipner/Utsira conditions
800

CO2 density: 760 ± 60 kg/m3

Density [kg/m3]

700

95% confidence

600
500
400
300

37C@1040m; 33K/km

200

41C@1040m; 37.5K/km

100

45C@1040m; 41.7K/km

00250

500

750

1000

12501500

Depth [m]PVT analysis together with gravimetric result give an upper bound of 770kg/m3 and a lower bound of 640 kg/m3 with 95% confidence.
Chadwick & OlaEiken 2008
AlnesRobet Arts,al. AndyGeophysics
Nov.

Kyoto, 9 december 2010

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Seafloor depth, frommultibeam echo sounding

Mozaic of side scansonar data[m]Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Overview• Introduction to the Sleipner CO2 injection site
• Analysis of the seismic monitoring data
• Gravity monitoring results• Seafloor imaging• Concluding remarks

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Closing remarks• No indications for leakage• Plume development currently in line with expectations at the topreservoir• Refinement of the characterization of the intra-reservoir behavior
still ongoing• Seismic monitoring and gravity monitoring provide
complementary information

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010

Acknowledgements• Most of this work has been carried out in the framework of the EU
projects SACS, SACSII, CO2STORE, CO2REMOVE. Theauthors are grateful to the different consortia for allowing thiswork to be presented.

Rob Arts, Andy Chadwick & Ola Eiken

Kyoto, 9 december 2010