Sleipner and Snøhvit Projects

CSLF Interactive Workshop, Saudi Arabia01-02 March 2011

Phil Ringrose, Ola Eiken and colleaguesCO2 Storage R&D Project, Statoil ASA

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Statoil’s CCS projects An Industrial Approach to Climate Change

Sleipner

In Salah

Snøhvit LNG

1996- 2004- 2008- 2011/12- 2018?

MongstadFull-scale

Test Centre Mongstad

Application to new challenges

(CCS Business)

Building up our knowledge and experience(R&D)

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Snøhvit Sleipner In Salah

Statoil’s CO2 Storage Sites

Unique blend of• Offshore/onshore• Shallow deep• Horizontal/vertical wells

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-60 -40 -20 0 20 40 60 80 100

Temperature [oC]

Pre

ssur

e[b

ar]

1

1

0

100

1

000

1000

0

Boiling line

Melting line

liquid

vapour

solid

Snøhvit

In Salah

Sleipnerwellhead

reservoir

Phase Behaviour at Operating Conditions

Down-hole gauges would be nice …… and now we have one at Snøhvit!

5

0

1

2

3

4

5

6

7

8

9

10

11

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1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Acc

umul

ated

inje

cted

CO

2[m

illio

n to

ns]

Sleipner

In Salah

Snøhvit

CO2 Injection Performance

16.5Mt CO2 stored so far (2010)

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Operating the Sleipner CO2 Project

1. Monitoring Data:Wellhead pressure and flow rate is monitored continuouslyGas composition samples are taken intermittentlySeveral Time-lapse (4D) seismic surveys:

1994 (baseline), 1999, 2001, 2002, 2004, 2006, 2008, 2010

Several Gravimetric surveys• 2002, 2005, 2009

2. Key Uncertainties:Role of internal Utsira shale layersReservoir and wellbore modellingLong-term storage capacity

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Sleipner CO2 Project Time-lapse Seismic Data

1994 2001

2008 2008-1994

8 1999200120022004200620081 km

Top layer

All layers

Incr

easi

ngam

plitu

de

Sleipner CO2 seismic monitoring

855

910

Tim

e [m

s]

0

5

10

15

20

25

30

0 2 4 6 8 10

mill. tons

amp

* are

a

injection point

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Other monitoring at SleipnerGravity surveys 2002, 2005, 2009

• In-situ CO2 density: 720 +/- 80 kg/m3

• Maximum dissolution rate: 1.8% per year

• Alnes et al. GHGT-10

Seafloor mapping 2006

CSEM survey also done• no interpretable signal

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Sleipner Modelling Insights

• Initial models built from pre-injection seismic:Coarse grid simulations which indicated a circular, dispersed plume.

• 4D monitoring data indicates a northerly extension to the plume propagation.

• IP modeling (Permedia Migration tool) gave closer matches to the seismic, indicating a dominance of gravity/buoyancy forces over viscous forces.

• Adjusted inputs to conventional reservoir simulations in order to capture enhanced gravity segregation and understand physio-chemical prosesses:

Gives better matches to seismic

Shows importance of Vertical Equilibrium (VE) assumption

Implies dissolution was previously overestimated

• Results presented in SPE Paper 134891, Singh et al, 2010.Now released as a reference model via IEA-GHG

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1999 2001 2002 2004 2006 2008

Seismic response map

IP simulator

FD simulator

N

Comparing Sleipner seismic response to modelpredictions – Layer 9 (SPE 134891)

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Sleipner Modelling: Lessons Learned• Detailed analysis of Sleipner Layer 9 (uppermost) reveals strong gravity

segregation and plume thinningIP Migration gives a good match to northern plume extension Use of Vertical (gravity) Equilibrium improves Eclipse simulator matchDefault simulators have too much dispersion and CO2 dissolution

• Long-term predictions and capacity estimates need to be based on models verified with short-term monitoring data (5 to 15 years)

• Now focusing on multi-layer model and effects of discontinuous shales

Some viscous forces

Gravity segregationThin diffusive boundary layer

)/( dSdPzg

CapillaryGravity

c

ΔΔ=

ρ1

)/( dSdPkxu

CapillaryViscous

cx

ox μΔ= 0

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The Snøhvit LNG/CCS Project, Norway

• Snøhvit (Snow White) is an LNG project, in the Barents Sea offshore Norway

• CO2 is captured onshore and transported in a 153km subsea pipeline to a subsea template.

• The CO2 is injected at a depth of 2600m into the Tubåen formation (below the gas reservoir).

• Injection of CO2 started in 2008, and so far 1.0 Mt have been stored.

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Snøhvit: Key Statistics

• CO2 injector line: 153 km• Seabed depth: 330 m• One CO2 injector• Injected gas is ~99% CO2

• Injected into Tubåen Fm at 2430-2600m depth

Reservoir system

Process Facility

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Snøhvit injection well10m

Perforated zones

Depth map of base Tubåen Fm.

2km

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Snøhvit CO2 monitoring

Top Fuglen Fm.

Base Tubåen Fm.

CO2 injectionwell

CO2 injectionwell

baseline 2003 repeat 2009 difference

0.5 km

Increasingam

plitude

Amplitude changes

Modelled CO2 saturation and pressure increase

Time

Pres

sure

200 000

300 000

400 000

500 000

600 000

Cum

ulat

ive

inje

cted

mas

s [to

ns]

Time

Pres

sure

200 000

300 000

400 000

500 000

600 000

Cum

ulat

ive

inje

cted

mas

s [to

ns]

4D seismicacquisition

10 bar

4 months

Eiken et al, 2010 (GHGT10)

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SnøhvitFlow Modelling• Currently working on improved

model and history match• Example shows CO2 plume

distribution at 2030 for different fault seal scenarios

With fault juxtaposition but no seal With disconnected faults

3D grid connections across fault

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Conclusions• At Sleipner and Snøhvit, single wells have successfully injected 0.4-0.9 million

tons of CO2 per year.

• Surface geophysical and well pressure monitor data give rich information on the storage behaviour:

Dynamic modelling is better constrained, but still challenging.

Indicates strong gravity segregation and minimal dissolution

• The actual plume development has been strongly controlled by geological factors which we learned about during injection.

• High-quality monitor data lowers the detection threshold for any potential leakage:

4D seismic monitoring confirms no leakage into the overburden.

• Detailed site characterization, reservoir monitoring/modelling and well solutions have allowed us to quantify the storage capacity and field performance:

Gives a good basis for scoping and optimizing future projects.

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References• Alnes, H., Eiken, O., Nooner, S., Sasagawa, G., Stenvold, T. and Zumberge, M., 2010.

Results from Sleipner gravity monitoring: updated density and temperature distribution of the CO2 plume. 10th International Conference on Greenhouse Gas Technologies, 19-23 Sept. 2010, Amsterdam, Netherlands. www.sciencedirect.com

• Eiken, O., Ringrose, P., Hermanrud, C., Nazarian, B. & Torp, T., 2010. Lessons learned from 14 years of CCS Operations: Sleipner, In Salah and Snøhvit. 10th International Conference on Greenhouse Gas Technologies, 19-23 Sept. 2010, Amsterdam, Netherlands. www.sciencedirect.com

• Singh, V., Cavanagh, A., Hansen, H., Nazarian, B. Iding, M. and Ringrose, P., 2010.Reservoir modeling of CO2 plume behavior calibrated against monitoring data from Sleipner, Norway. SPE paper 134891 presented at the SPE Annual Technical Conference and Exhibition held in Florence, Italy, 19–22 September 2010.

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Thank you