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www.slb.com/carbonservices/www.slb.com/carbonservices/

Geological Storage -Risk Assessment & Monitoring

IEA GHG Summer School, Norway

David White 24th August 2010

Schlumberger - over 80 years of history & technology

First electrical log run by Marcel and Conrad Schlumberger

Pechelbronn, Alsace, FranceS t b 5 1927September 5, 1927

Schlumberger today

People:● 80,000● 140 Nationalities● Working in over 80 countries

Services:● Reservoir characterization● Reservoir characterization● Reservoir production● Drilling & Measurements● Integrated Project Management

2009 Financials:● $22.7 billion revenue● $3.1 billion net● > $800 million on

Research & Development

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Schlumberger Carbon ServicesHighlights

People• A full Asset team dedicated to CO2 storage• >100 experienced technical staff

Experience in CO2 storage• More than 10 years experience in CO2 storage• Numerous ongoing projects worldwide including the • Numerous ongoing projects worldwide including the

regional partnerships in the USA, the Otway project in Australia, Ketzin in Europe.

Technology for CO2 storage• Unique set of process and technologies for CO2

storage• Dedicated research and engineering activities • More than 100 publications on CCS

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Global CO2 Storage Sites/Projects with Schlumberger Activity

Weyburn, CanadaSnøhvit, Barent Sea

Sleipner, North Sea

>60 CCS projects/studies globally

In Salah, AlgeriaGorgon Field, 130 km offshore NW AustraliaLarge

CCS projects

Large CCS

projects

Global CO2 Storage Sites/Projects with Schlumberger Activity

American Electric Power Company, Inc. (Ohio)

North Sea customer A - 2009

North Sea customer B - 2009PGE Belchatow - 2010

Vattenfall Jaenschwalde - 2010

Illinois Basin - Decatur Project - 2009

Southern Company Services, Inc. (Alabama)

Repsol Spain - 2009

Reggane, Algeria - 2009

Site pre-selection for ENI (4 sites) - 2008

CO2CRC – Otway Project – 2006-2010

Lassie, Australia

>60 CCS projects/studies globally

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Risk assessment and Monitoring for CO2 storage!

Why Monitor? – Manage Risk

Risk =

“ (Impact of Undesirable Occurrence)x x

(The Probability of its Occurrence)”

But it is not that simple……

Risk Perception Public vs. Experts

Public Feels - The Dread Factor- reacts very negatively to “worst-case” risk assessments,

Public: Risk Size= (“Known” factor)*(”Dread” factor)

Experts Calculatep- tend to rely on quantifiable “realist” perspectives,

Risk Size= (Probability)*(Loss)

Expert risk studies are rarely effective for convincing the public that a proposed project is safe.

Thesis by Gregory Singleton, MIT May 2007

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Risk Perception Public vs. Experts

Public Feels - The Dread Factor- reacts very negatively to “worst-case” risk assessments,

Public: Risk Size= (“Known” factor)*(”Dread” factor)

Experts Calculatep- tend to rely on quantifiable “realist” perspectives,

Risk Size= (Probability)*(Loss)

Expert risk studies are rarely effective for convincing the public that a proposed project is safe.

Thesis by Gregory Singleton, MIT May 2007

CCS Risk Types

GENERAL RISKS

● Public acceptance● Economic● Legal

TECHNICAL RISKS:

Key Concerns: Leakage & Seismicity

● Extreme events (major releases)● Ground fresh water resources contamination● Soil contamination● Leaks

● Risk Acceptance Criteria● Standards● Regulations and Policies

Risks can be managed – we do it all the time

● Evaluate & Understand● Model & Simulate● Measure & Monitor● Mitigate ● Experiment and

Demonstrate

(I bet they tried it with a dummy first ……and it might be a fake!)

http://www.youtube.com/watch?v=UXXC2etJeZQ

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What do we need?

Finding the right Storage Site

Injectivity:The ease with which the CO2can be injected

Other:• Environment• Infrastructure• Regulation• Public opinion• Finance

…the best risk reduction approach is to choose the right site in the first place

Capacity:The amount of CO2 that can be safely stored

Containment:The ability to store CO2safely and permanently

CO2 Monitoring – 3 objectives

BoundariesBoundaries

ContainmentContainment

#1: Watch stored CO2

#2: Watch possible leakage paths

#3: Monitor the environmentWell Integrity

Sealed fault

Monitoringwell

Abandonedwell

Monitoringwell

CO2injectionwell

Freshwateraquifer

Drawing from the Oilfield: Static and Dynamic Modeling Workflow

Surface imaging Mapping

Data inputLog interpretationand correlation

History match

Fault and Fracture modelling

3D Geological model Reservoir and Aquiferproperty population

3-D flow simulationGeochemistryGeomechanics

ECLIPSE

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Surface imaging MappingEM survey interpretationData input

Information managementGIS database

Log interpretationWell correlationSurface identificationSurface/subsurface interaction

CalibrationHistory matchPost processingPresentation

Data analysisFacies modellingFault modellingFracture modellingHydrodynamic test analysis

CO2 Storage Site Modelling Workflow

Uncertainty analysisUpscaling processesReservoir and Aquifer property population

3D flow simulationGeochemistryGeomechanics

Eclipse

3D Geological model3D Property model of the Reservoir and the Overburden

Zooming in on the sub-surface

The Need for Technology: Hi-Res versus Conventional

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Storage Lifecycle And where is CO2 storage readiness

DevelopmentDevelopmentCO2 InjectionCO2 Injection

ClosureClosure

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Pre SelectionPre Selection

AppraisalAppraisal

Post closurePost closure

Post liability transferPost liability transfer

Performance Management & Risk Control

Performance Management & Risk Control

Pre-injection Injection Post-injection

Designing a monitoring plan

Minimize Costs:

For each technique, For the overall plan over time

Reduce Risk & Optimize Performance:

Added value for the operator

Abide by laws & Regulations:

EU CCS, EU ETS, state law

Site & technicalconstraints:

Deployment restrictions,Measurement sensitivity

Monitoring Plan

Performance & Risk Analysis for CO2 Storage

Measurements (characterization)

• Seismic• Data wells

Measurements (Monitoring)

• CO2 injection• CO2 location

• Sensor selection and specification• Sensor response prediction

Models

• Structure• 3D static

• Monitoring sensor placement

• Storage integrity

• Measurement interpretation• Model update

Performance & Risk Assessment

• Injection efficiency • CO2 in place• Leakage scenarios & rates• Risk ranking

• CO2 migration• Cap rock failure • Well materials degradation

• Dynamic

Intervention,Remediation

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Reducing Uncertainty & Risk over time

Certification at start

Injection start

Characterisation

Site Design & Monitoring Strategy

Uncertainty & Risk

Simulation

Uncertainty & Risk Intervention & Remediation

TimeTransfer of liabilities

Monitoring Simulation

Remediation

Injection stop

Monitoring challenges

Range of scales● Time - from the very short to the very long● Space - from the very small to the very large

You can’t directly measure what you want to…● Spatial distribution and concentration of CO2

● Sealing boundaries capacity permeability● Sealing boundaries, capacity, permeability.

You can’t measure where you want to…● Confined to the surface or wells

…BUT you measure what you CAN and construct models● Consistent with available information● Improve with time● With some predictive power (within limits)

Questions for Designing a Monitoring System

● What do I want to monitor?● What property change can I monitor?● What variation am I considering?

● What measurement technique to use?● What should be my sensor

ifi i ?

● CO2 movements, leaks…● P, CO2 Saturation, Resistivity

● Accuracy / Precisionspecifications?

● Where should I place my sensor?● For how long?● How can I deploy it?● How can I interrogate it?

● How can I interpret the measurement?

● Surface, Obs. Well ● (Permanent, Logging…)

● Operation phase, surveillance

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CO2 Monitoring

monitoring wellAssurance Monitoring (Environment and HSE environment)

Operational Monitoring

injection wellmonitoring well abandoned well

spill pointopen fracture

fractured cap rock leaking

well

freshwater aquifer

Spill pointsSpill points

ContainmentContainmentWell IntegrityWell Integrity

Old wellMonitoringwell

Monitoringwell

Injectionwell

Freshwateraquifer

Sealed faultSealed fault

Tracking the CO2 plume

Verification Monitoring(Watch possible leakage paths)

g

Integrated CO2 Storage Monitoring Programme

Geophysical techniques: Seismic, VSP’s, EM techniques, MicroseismicsLogging: Saturation (Resistivity, Sigma), Well integrity (Casing corrosion, cement bond)Sampling: Pressure, Fluid properties, CO2 concentrationPermanent sensors: Pressure, Temperature

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100

1000

10000

utio

n, m

Tracking CO2 evolution – what we can see

CSEM(Offshore only) Gravity

(Onshore only)

InSAR

Size = relative cost

0.001

0.01

0.1

1

10

Verti

cal R

esol

u

Areal Reservoir Coverage

In-wellmeasurements

4D Seismic

Surface-to-wellmeasurements

Well-to-well(Seismic, EM)

Microseismic(Onshore)

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What we can monitor?

CO2 Saturation (neutron, density, resistivity, sonic)Sampling, downhole fluid analysisCased Hole Formation ResistivityPressure & Temperature

2D, 3D SeismicMicroseismicGravimetry (to back up time-lapse seismic)Echosounding, Seafloor samples

In boreholes From the surface

Pressure & TemperatureWell Integrity (Cement, Corrosion)Electrical resistivity tomography (ERT)MicroseismicX-well seismicX-well EMDistributed Temperature SensingTiltmeters

Echosounding, Seafloor samplesNoble Gas TracersMT (natural source plane wave electrical method)CSEMInSAR (Satellite Radar Imaging)

CO2 Saturation Measurement - Ketzin

CO2 Saturation ~ 60% in

Contrast between formation water and CO2 properties can be detected by neutron capture cross-section, hydrogen index, density, resistivity and sonic velocity to quantify the amount of free-phase CO2 present in the pore volume.

2 %upper sand section (yellow).Little presence of CO2 in lower sandNo CO2 above 625 m

625 m

CO2 presence over 4 week interval

Site feasibility

• Are there any wells on the potential storage site?• Do we have access to the well data?• If yes, can we assess the current state of the wells?

Site appraisal

• What data do we need to acquire to assess/reduce the risk of leakage from wells?

• What data do we need to satisfy regulatory requirements

Well integrity risk: questions…

EU regulations state that risk of leakage from apotential storage site must be assessed before astorage licence can be granted.

During operations, risk assessment drives sitemonitoring, post-closure and liability transfer plans.

Concept selection

• Can we convert existing wells to CO2 injectors? • Does any well pose a risk of leakage during project life?• If yes, how could the risk be managed/eliminated?

FDP

• What is the residual risk of leakage from the wells?• What remediation/contingency plans need to be in place during operations life?

• What monitoring plans will be implemented during injection?

Pitting Corrosion

Cement Alteration

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Wellbore Integrity

Acoustic: imaging

Isolation Scanner of the formation wall through casing and cement reveals hole enlargement

Mechanical: multi-finger

caliper

Electromagnetic technology - Local applicationCross-well Electro-Magnetic

A primary electromagnetic field is generated from a first well, inducing currents in the formation and a secondary EM field, detected by receivers in the second well.It has a limited resolution but could be used to track the CO2 plume, possibly in conjunction with seismic methods.

Remote sensing technology - InSAR

Ground deformation monitoring using radar imaging by satellite.

We can calculate the expected changes in surface elevation based on pressure changes and a 1D Mechanical Earth Model.

This allows us to decide if a satellite acquisition will provide the required resolution (several mm).

From Mathieson et al. GHGT9; 2008

Interferometric synthetic aperture radar is a space borne geodetic tool used to obtain high spatial

resolution surface deformation maps.

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Global measurements

Time-lapse Seismic GravimetrySensitive to formation density

CO2 replacing water can be detected due to contrast between CO2 and waterGravimeters are placed at the surface or downhole

Sleipner 4D: Courtesy of Statoil

InSARElevations determined from Synthetic Aperture Radar (SAR) images by interferometric methods.Uses two (microwave) antennas, displaced either vertically or horizontally, installed on the same satellite or aircraft platform.One of the antennas transmits the signal, but both receive it, resulting in two images being created.

Magnetotelluric (MT)Measures the natural low-frequency electromagnetic field of the Earth

AssuranceMonitoring

• Potable water quality• Soils acidity• Atmospheric concentration• Surface deformation

Impact: HSE monitoringInjection operation control• Wellhead pressure• Bottom hole Pressure

and Temperature• Injection rate• Microseismicity

Well Integrity• Annulus pressure• Corrosion• Cement• Soil gas measurements

VerificationMonitoring

OperationalMonitoring

VerificationMonitoring

OperationalMonitoring

Objectives of the monitoring plan - Summary

Tracking the CO2 plume

• Geophysics techniques • Pressure, Temperature• Well logs (CO2 Saturation)• Sampling• Geodetic methods

Quantification of leaks

• Soil gas measurements• Surface gas measurements• …

c ose s c ty

Quantification of injected CO2

• Mass flow• Gas stream composition

and phase

Cap Rock / Fault Integrity

• Microseismicity• Pressure interference

Detection of leaks/migration • Sampling & chemical analysis• Geophysics techniques• Pressure interference• Soil gas measurements• Vegetation stress• Eddy correlation tower

Conclusion: Monitoring as part of Minimizing Storage Risk

Containment – THE storage issue:● Failure of sealing cap rock● Permeable faults and fractures● Migration along wellbores

Risk reduction through:

CapacityCapacity

InjectivityInjectivity

ContainmentContainment● Choosing the right site● Detailed reservoir characterization● Comprehensive modelling● Ongoing monitoring

Risk mitigation through:● Remediation methodologies● Risk-based approach to project

management

Monitoring:● Different types of monitoring objectives● Existing technologies and tools● More work/research on the integration● Closely related to Modelling