Seismic Monitoring of CO2 Injection at theIEA Weyburn CO2 Monitoring and Storage
Site: Summary of Phase I Results
Don White, Geological Survey of Canada

RITE International Workshop on CO2 Geological Storage, Tokyo,Feb. 21, 2006

International Workshop on CO２ Geological Storage , Japan ‘06

Outline• Geological Storage of CO2 in Canada• The Weyburn CO2 Flood• Prediction of CO2 Movement• Seismic Monitoring• Volumetrics• Conclusions

International Workshop on CO２ Geological Storage , Japan ‘06

Geological Storage
Sedimentary Basins• Depleted oil andgas reservoirs

Coal Beds• Coal beds
• Saline aquifers• Gas hydrates*Oil/Gas
Reservoirs
SalineAquifers

Other• Deep Ocean• Marine sediments* Arctic Canada, East and West Coasts• Ultramafic rocks

International Workshop on CO２ Geological Storage , Japan ‘06

Sleipner Time-Lapse Seismic
1994

1999-1994

2001-1994

top Utsira
Fm.
50 ms
1000 minjectionpoint

injectionpoint

injection
point

From Eiken et al. 2004
International Workshop on CO２ Geological Storage , Japan ‘06

Examples of CO2 Volumes• Average auto: 4 t/yr

– 98 Mt annually (Canada)• 250 MW generator: 10 Mt/yr• Weyburn Capacity (20-30 Mt)

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Inventory of Storage Capacity

WCSB Storage – Estimates:
450 MT
CO2 EOR
Depleted Reservoirs
Oil:
111 MT
Gas:
13,200 MT
ECBM
100,000 MT
Saline Aquifers
1,000,000 MT

900 m depth

supercritical gas

International Workshop on CO２ Geological Storage , Japan ‘06

Good Geographic Match Between Best
Storage Areas and Major Sources
AGS/EUB - Inventory of CO2 Sources in WCSBInternational Workshop on CO２ Geological Storage , Japan ‘06
7

WCSB Saline Aquifers, Coal Beds

• Regionally extensive (100’s km)• Large volume• Isolated by aquitards/aquicludes
International Workshop on CO２ Geological Storage , Japan ‘06

1. The IEA Weyburn ProjectInternational Workshop on CO２ Geological Storage , Japan ‘06

International Workshop on CO２ Geological Storage , Japan ‘06
International Workshop on CO２ Geological Storage , Japan ‘06

Objectives• Develop methods for monitoring CO2 injection.
• Improve reservoir characterization to enhance
conformance control and prediction .
• Verify volumes of CO2 in the subsurface.
• Establish safety and containment of injected
CO2.

International Workshop on CO２ Geological Storage , Japan ‘06

Weyburn Research Themes• Geological Characterization• Prediction, Monitoring & Verification ofCO2 Movement• CO2 Storage Capacity, Distribution &Economics• Long-Term Risk Assessment

International Workshop on CO２ Geological Storage , Japan ‘06

The Source of CO2••

Dakota Gasification
Company250 mmscfd CO2 by-productof coal (lignite) gasification

ReginaWeyburn
Saskatchewan•

95 mmscfd (5000 tonnes/day)contracted and injected atWeyburn•CO2 purity 95%•

EnCana currently injects 120
mmscfd (i.e. 21% recycle)

Manitoba

EstevanCanadaUSA

Montana

North DakotaBeulahInternational Workshop on CO２ Geological Storage , Japan ‘06

BismarckWeyburn Field: Phase 1A EOR Area

International Workshop on CO２ Geological Storage , Japan ‘06

The Reservoir (Fractured Carbonate)

Reservoir: 1450 m depth, <30 m thick, T=63O C, P=14 MPa
Anhydrite seal
Marly Dolostone: 6 m thick, 16-38% porosity, 1-50 mD perm
17 m thick,
Vuggy
Limestone:
International
Workshopon CO２ Geological
Storage ,porosity
Japan ‘06 8-20%, 10-300 mD perm

The CO2 (Miscible) Flood
Hz Producer
Hz CO2 Injector

MidaleAnhydrite

MarlyOil&Water

CO2 & Oil

CO2CO2

Oil & CO2Vuggy

Water

Frobisher
VerticalProducer
International Workshop on CO２ Geological Storage , Japan ‘06

Vertical Water
InjectorProperties of CO2
Weyburn
Reservoir fluid properties (for P=15-25 MPa;
T=63 deg C) summarized from Brown (2002).
Fluid

Oil

Bulk
Modulus(GPa)1.2-1.7

Density(gm/cc)Brine

2.7-3.2

1.021.08

~1/10

1-2

CO2

0.05-0.18

0.580.76

1/70

100

0.800.88

Viscosity(relativeto oil)1

Solubilityof CO2(molar %)66

Reservoir: T=630 C, P>15 MPa

International Workshop on CO２ Geological Storage , Japan ‘06

Model Response (Gassmann)

1-2%

Marly8%Vuggy

Post-injection (100% brine replaced by 70% CO2+30% brine)
Pre-injection

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Monitoring Schedule3DCO2Fluid/Seismic Injection Gas

3.5 MT2003
M2

2.6
MT50bcf

M1

1.2
MT23 bcf

BLbcf
00MT2002

2001

2000

M2
M1
BLMonitor 2Monitor 1Baseline

International Workshop on CO２ Geological Storage , Japan ‘06

SoilGas2. Pre-Injection Prediction
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Pre-injection Prediction
CO2 Saturation

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Pre-injection Prediction

PressureInternational Workshop on CO２ Geological Storage , Japan ‘06

3. Monitoring of CO2 Movement and Effects
at the Reservoir

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Monitoring Techniques• Production Data
• Geochemistry of Production
Fluids/Gases• 3D Multi-component Time-LapseSeismic• Passive Microseismic Monitoring• Soil Gas Sampling

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Time-Lapse Seismic• P- and S-Wave– pressure vs. saturation– fractures (S-wave splitting)• Time delays & Amplitude differences– vertical discrimination

International Workshop on CO２ Geological Storage , Japan ‘06

Weyburn SeismicInternational Workshop on CO２ Geological Storage , Japan ‘06

Monitor 2 Time-Lapse Amplitude
Difference
NW

HZ Injector

HZ Injector

1000

HZ Injector

SE1000733

L.Gravelbourg
Watrous467

1100

200Time (ms)Mississipian
Frobisher

01200

-199

Artifacts

Bakken1300-466-732-999

Inline-128

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Monitor 2 Production-Seismic
Comparison

International Workshop on CO２ Geological Storage , Japan ‘06

CO2 distributions from Seismic and Simulator, 1stiteration (Monitor 2 Survey)
Seismic

Simulator
0.5
0.4
0.3
0.2
0.1

International Workshop on CO２ Geological Storage , Japan ‘06

Amplitude Anomalies at the Reservoir

International Workshop on CO２ Geological Storage , Japan ‘06

Shear Wave Splitting

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S-Wave Splitting

International Workshop on CO２ Geological Storage , Japan ‘06

S-wave vs. P-wave Amplitude
Difference Anomalies

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Repeatability>98%International Workshop on CO２ Geological Storage , Japan ‘06

Microseismicity: Plan View

Injection Well

Monitoring Well

CO2 Response

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Start of Injection

4. Volume Estimation

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First-Order Volumetrics
Reservoir Properties:
T=63 deg C
P= 15 MPa
Porosity=0.13
Thickness=23 m
2001 Seismic 2002 Seismic
Injector vol./CO2 vol. vol./CO2 vol.
Area
Ratio
Ratio
1
5.3
6.3
2
8.6
12.6
3
5.4
6.2
4
3.1
4.0
Total
4.6
5.5

Mean Saturation=0.19-0.23

International Workshop on CO２ Geological Storage , Japan ‘06

Net CO2 injected vs seismic estimate

Assumes average Sg of 0.20

International Workshop on CO２ Geological Storage , Japan ‘06

Summary & Conclusions• Monitoring methods clearly show physical andeffects associated with CO2 injection.
• Seismic methods show robust time and amplitudeanomalies.

– P-wave amplitudes are highly sensitive to CO2-rich gas
phase at low levels of saturation (5-10%); good fordetection, but makes volume estimation difficult.
– Volumetric analysis of seismic anomalies: mean CO2
saturation of ~20%, similar to reservoir simulator results.
– Vp changes of up to 12%: mainly Sg with secondary P
effects (2-3%).
– Off-trend anomalies identify areas of CO2 channelling.
– Sensitivity of amplitude response to upper reservoirchanges (Marly unit) allows partial discrimination ofvertical CO2 distribution.

International Workshop on CO２ Geological Storage , Japan ‘06

Summary & Conclusions– 1.4 million m3 (2500 tonnes) of CO2 is the minimum detectableamount using time-lapse surface seismic. This estimate may beoverly conservative by an order of magnitude.
– No evidence for CO2 escaping from the reservoir. Based solely
on the seismic results, the maximum amount of CO2 that may
have migrated above the reservoir is <2% of the total injectedvolume.
– Contribute to more accurate reservoir flow simulations.

• Microseismicity is low level.
– 60 microseismic events with M=–3 to –1 during 6-months.
– Events associated with production/injection changes (e.g.,water-to-gas) where pressure transients might be expected.
– Induced microseismicity is less than for water flooding thathas occurred for more than 30 years.

International Workshop on CO２ Geological Storage , Japan ‘06

Acknowledgements• Tom Davis, Colorado School of Mines• Keith Hirsche, Hampson-Russell Software• Ernie Majer, Lawrence Berkeley NationalLaboratory• Shawn Maxwell, Engineering Seismic Group• Hubert Fabriol, BRGM
• Geoff Burrowes, Sandy Graham, Ryan Adair,David Cooper, David Hassan, Guoping Li,EnCana

International Workshop on CO２ Geological Storage , Japan ‘06

IEA Weyburn CO2 Monitoring and Storage ProjectAn International Collaborative ResearchProgram Led by the PTRC Basedin Regina, Saskatchewan, Canada

QUESTIONS ?
SPONSORED BY:
Natural Resources
CanadaRessources naturelles
CanadaEuropeanCommission

As well as 8 Industry Sponors:
BP, ChevronTexaco, Dakota Gasification Co, Engineering Advancement Association of Japan,
Nexen Canada, SaskPower, Total and TransAlta Utilities Corp.
International Workshop on CO２ Geological Storage , Japan ‘06