igc 2008 in salah presentation aug08

8/8/2019 IGC 2008 in Salah Presentation Aug08

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Classification: Internal Status: Draft

Assessing the long-term performanceof the In Salah C02 Storage Site

33rd International Geological Congress, Oslo, August 11th 2008

Philip Ringrose & Martin Iding, StatoilHydro ASAIn Salah CO2 Joint Industry Project

Outline:

1. Summary of In Salah CO2 storage site

2. Long-term performance assessment3. Future challenges


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The In Salah CO2 storage site at Krechba

Cretaceous

sequence(900m)

Carboniferous

mudstones(950m)

Definition and modelling

of reservoir storage andmigration

Reservoir (

20-25m

thick)

Definition andmodelling of potential

cap-rock pathways

Gas Chemistrymonitoring

Fluid displacementmonitoring(4D seismic)

Rock strain monitoring(Tilt, MEQ)

Density changemonitoring

(Gravimetry)

Production

monitoring(Tracers)

CO2 injection(3 wells)

Gas production(5 wells)

Gas fromother fields

Amine C02 removal

Satellitemonitoring

(PSInSAR)


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KbKb--1313

KbKb--55

KbKb--502502

KbKb--503503

KbKb--1111

KbKb--1212

KbKb--501501

KbKb--1414

Krechba PlantKrechba Plant

KbKb--55

KbKb--502502

KbKb--503503

KbKb--1111

KbKb--1212

KbKb--501501

KbKb--1414

Satellite Monitoring Summary

Time-lapse inversion ofSatellite data (Envisat)

Permanent ScattererInterferometry

(PSInSAR)

Lawrence Berkeley (US)and TRE (Milan, Italy)

Indicates a critical-staterock mechanical system

Method published byVasco et al. (2008)

PS

Back-scatterphase-shiftanalysis(time-lapse)

Radar

Up to5mm/yrrelative

uplift

~2mm/yrrelative

subsidence

Faultco

ntro

l?

5km


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Sub-surface dataset:

Well data andoverburden model

PossibleFault/fracturezone?


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Subsurface dataset:

Downhole gas data

Reservoir CO2 mole fraction is c. 1.3% Downhole CO2 varies around mean close to

atmospheric (385ppm) but with a huge range(0-100000 ppm or 0-10%)

High CO2 fractions in caprock/overburden probablyindicate locally-generated source-rock CO2

Ongoing work to better understand origin ofoverburden gases

Natural CO2 in

overburden

CO2 in gasreservoir

Head gas and Isotubes samples from two wellscharacterise the pre-injection gas distribution:


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Subsurface dataset:Rock characterisation

Cretaceous Sandstone

Upper caprock (C20); ~650m thick;Dark grey mudstone with occasionaldolomite layers.

Lower caprock (C20.17), ~150m thick:

Distal deltaic to marine mudstone. Tight sandstone (C10.3); 15-20m thick:

Very-fine grained tidal-heterolithicsandstones. Strongly quartz cemented.

Reservoir/Aquifer (C10.2), 20-25m thick:Fluvial-dominated, tidal-deltaic

sandstone; =18+5%, k=0.1-100md

Heterolithic interval from C10.2 reservoirshowing wavy laminated bedding in atidally-influenced delta setting

Carbonife

rous

Visan

Tour

nasian

Cret.

Dev.


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Carboniferous time slice(C10) Semblance cube

Some clear EW Faults

East margin has sub-seismic deformationrelated to deeper faults

kb-502

Fractureorientation

Subsurface dataset:Structure, faults and fractures

Broad Carboniferous foldinfluenced by underlyingDevonian faults

Strike-slip tectonicsetting

Evidence for conductivefractures from well data

Fractures controlled bypresent-day stress field:

H = NW-SE


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Long-term Performance Assessment

So how do we assess the likely long-term behaviour of CO2?

1. Build on framework developed by the IPCC:

Special Report on Carbon dioxide Capture and Storage, 20052. Engage R&D community:

CO2ReMoVe project (EU), LLNL/LBNL (USDoE)

3. Adapt oil industry tools:

Basin exploration, oil production forecasting, risking.

Following results are based on a preliminary assessment of CO2injected in one of the three wells at the In Salah storage site


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316

1000

3162

10000

Years

FractionofSubs

urfaceCO2

Caprock storageReservoir storage (moveable)

Aquifer storage (moveable)

Residual CO2 fluid

Aqueous solution

Mineral precipitation

Forecasting the long-term fate of subsurface CO2

CO2 in aquifer(mobile phase)

CO2 migrationinto gas reservoir

Residual CO2(immobile)

Forecast

Long-term uncertaintyHistory

Dynam

icsimulations

Geochemical reactions

Concept and Approach


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3162

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Years

FractionofSubsurfaceCO2

Caprock storageReservoir storage (moveable)

Aquifer storage (moveable)

Residual CO2 fluid

Aqueous solution

Mineral precipitation

Forecasting the long-term fate of subsurface CO2

Forecast

Long-term uncertaintyHistory

Estimates

Ongoing R&D

New simulators

Current

simulatoroutputs

Caprock storage: Important forunderstanding long-term containment

Storage domains

Preliminary Results(Simplified Flow Physics)


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Using the Permedia MPath simulator: Invasion percolation model of gasphase into brine-filled pore space controlled by capillary entry pressure

Based on best estimate fluid and rock properties but neglects multi-phasemixing and geochemical reactions

MPath forecast forinjection from well 502

CO2 migration after

100 years

Colours indicate invasiontime sequence

Long-term simulation of CO2 migration


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Short-term simulation of CO2 migration

Detection of CO2 atobservation well after2 years injection from

well 502 gives us acalibration point for thelonger-term forecasts.

Preliminary modelgives plausible match(after 2 years)

Many of factors

affecting CO2 plume(multi-phase mixing)

The challenge offracture flow requires

further work toimprove forecasts

1km


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The Fractured Rock Challenge

a. Partially cemented conductivefracture ~0.8mm wide

b. Cemented fracture at 10o angle

a

b

Fractures and small faults are evident fromcore analysis, image logs and dynamic data

Satellite surface deformation observationssuggest a reactive rock mechanical system

Modelling of CO2 transport in fractured rock isa significant challenge ongoing R&D atImperial College, LLNL and others.


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Geomechanical model (stress & strain)

The Fractured Rock Challenge

Work in progress to buildfractured-rock models ...

Structural geological model

Reservoir simulation(pressure and flow)

Discrete fracture network model


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Acknowledgements

1. Previous work and contributions from the In Salah CO2 JIP Project

2. Technical contributions from the In Salah Gas Joint Venturesubsurface team

3. Permission to release data from Sonatrach, BP and StatoilHydro

4. Contributions from research partners:

EU CO2ReMoVe R&D Partners USDoE Lawrence Berkeley & Lawrence Livermore National Labs

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Model Assumptions (back-up)

Fluid Densities: CO2 450 kg m-3; Brine 1060 kg m-3

Endpoint saturations: Critical gas saturation, Sgcr = 0.25 and connate watersaturation, Swc = 0.2-0.5

3D model grid: 200x200x5m regular grid (5.6M cells)

Capillary threshold model based on published Hg-intrusion data(Schlmer and Krooss, 1997) calibrated to porosity model

Horizontal anisotropy due to fractures modelled using Pth(Y) = 0.1 Pth(X)

CO2 dissolution and precipitation rates based on typical (order of magnitude)published mass fractions (e.g. Obi & Blunt 2006):

CO2dissolved = 0.2 x CO2

residual:

CO2mineral = 00.5 x CO2

residual (Increasing with time)

igc 2008 in salah presentation aug08

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