Monitoring Geologic Sequestration: Transition from Demonstration to Commercial Environments: Questions for

Discussion Susan Hovorka

Gulf Coast Carbon CenterBureau of Economic Geology

Jackson School of GeosciencesThe University of Texas at Austin

Presented to RWG of SECARBJanuary 31, 2007

Monitoring Options• Atmosphere

– Ultimate receptor but dynamic• Biosphere

– Assurance of no damage but dynamic

• Soil and Vadose Zone– Integrator but dynamic

• Aquifer and USDW– Integrator, slightly isolated from

ecological effects• Above injection monitoring zone

– First indicator, monitor small signals, stable.

• In injection zone - plume– Oil-field type technologies. Will not

identify small leaks• In injection zone - outside plume

– Assure lateral migration of CO2 and brine is acceptable

Aquifer and USDW

Atmosphere

Biosphere

Vadose zone & soil

Seal

Seal

CO2 plume

Monitoring Zone

A balanced and phased approach to permitting and monitoring

Not too restrictive: encourage early entry into CCS – gain experience;

Learn by doing

Adequate rigor to assure

that early programs do not fail

Standardized, parsimonious

Early (now)

Mature (As defined by time? Or byinjection volume?)

Adequately rigorousto assure performanceand public acceptance

Phased Balanced

The Question of Balance: How Much is Enough?

4-D seismic

MonitoringMitigation/Corrective

Action

PublicParticipation

Less

M

ore

3-D seismic

Multiple in-zone wells

Regional +injection well

Test program

Site Characterization

Multiple zonesmultiple tools

MITsurface pressureinjected volumes

Selected toolsSelected zones

Redundantinjection sites/

pipeline system

Response ifnon-compliance

occurs

Stop injection

Litigation

Public comment& responsemechanisms

Public hearings

Public information

Examples, not an exhaustive list

Phased Approach

• Brine aquifer demonstrations and experiments in are class 5; EOR demonstrations and experiments are class 2

• What is the distinction between demonstrations and experiments and commercial projects?– Timing?– Injection volume?– Approach e.g. research goal?– How does a well convert from a demonstration to commercial?

• Relevance to FutureGen and DOE NETL RCSP Phase III projects as well as various projects in planning.

• How are mature commercial CO2 injection wells permitted?– Work underway by EPA, IOGCC, partnerships, national labs

The Question of Balance: How Much is Enough?

4-D seismic

MonitoringMitigation/Corrective

Action

PublicParticipation

Less

M

ore

3-D seismic

Multiple in-zone wells

Regional +injection well

Test program

Site Characterization

Multiple zonesmultiple tools

MITsurface pressureinjected volumes

Selected toolsselected zones

Redundantinjection sites/

pipeline system

Response ifnon-compliance

occurs

Stop injection

Litigation

Public comment& responsemechanisms

Public hearings

Public information

Texas Class I

Texas FutureGen

Change in risk with volume of injection

• Footprint of the plume and cone of higher pressure becomes larger as volume increases, and will change with time as injection continues.

• Large plume and large increased pressure increase risk of encountering a flawed seal or creating an unacceptably large brine displacement.

• Stacking injection in multiple zones or thicker injection interval will reduce footprint and impact of displaced brine

CO2 plumeElevated pressure

Monitoring Options• Atmosphere

– Ultimate receptor but dynamic• Biosphere

– Assurance of no damage but dynamic

• Soil and Vadose Zone– Integrator but dynamic

• Aquifer and USDW– Integrator, slightly isolated from

ecological effects• Above injection monitoring zone

– First indicator, monitor small signals, stable.

• In injection zone - plume– Oil-field type technologies. Will not

identify small leaks• In injection zone - outside plume

– Assure lateral migration of CO2 and brine is acceptable

Aquifer and USDW

Atmosphere

Biosphere

Vadose zone & soil

Seal

Seal

CO2 plume

Monitoring Zone

Frio 1 Pilot: Cross-Comparison of Multiple Types of Measurements

Downhole P&T

Radial VSPCross well Seismic, EM

Downhole samplingU-tubeGas lift

Wirelinelogging

Aquifer wells (4)Gas wells Access tubes, gas sampling

Tracers

Determine the subsurface distribution of injected CO2 using diverse monitoring technologies

Frio 2 Monitoring Design:Test of buoyancy, residual saturation, dissolution

Injection Well Observation Well

50 m

U-tubes

RST logs

Frio “Blue”

Sandstone

15m thick

PackersDownhole P and T

Tubing-hung seismic source

and hydrophones

Injectionwell

Otway Pilot (Australia) Time Structure Map

From Sandeep Sharma, OBPP, CO2CRC

Otway Pilot (Australia) Key Monitoring Objectives

• Confirm conduct all tasks safely and to the satisfaction of all stakeholders.

Assurance Monitoring (no leakage)

• Soil and atmospheric measurements to confirm non leakage/seepage of injected Co2.

• Hydrogeological monitoring to ensure no leakage of CO2 into the overlying aquifers

Storage Integrity Monitoring (predicted behaviour)

• Monitor the injected CO2 plume to :

– Validate migration paths - geophysics

– Validate migration times - geochemistry

– Validate likely shape - reservoir properties

– Validate geomechanical integrity - dynamic behaviour

From Sandeep Sharma, OBPP, CO2CRC

Otway Monitoring Technology Options • Data acquisition programs and frequency of time-lapse measurements

– Implications and tradeoffs vs completion design

– Prioritization of relative importance of each measurement to ease decision making

Objective Criticality SurfaceSeismic & VSP

micro

Seismic

Water Wells

Atmospheric

Soil Gas

U tube

RST SFRT Integrity Logs

Breakthrough detection

Plume shape

Plume travel path

Plume travel speed

Containment

CO2 area of accumulation

Public Acceptance

From Sandeep Sharma, OBPP, CO2CRC

Otway Pilot (Australia) Soil Gas Sampling Monitor gas compositions in the soil to order to measure any near surface change in CO2 composition or concentration

-25

-20

-15

-10

-5

100 1000 10000 100000CO2 ppm (vol)

13C

CO

2 (

o/ o

o)

Otway Pilot area

Cape Grim air 2001

Otway air 2005

Airbackground

organic matter 'decomposition'

deep subsurface

Otway natural gasrange

average

From Sandeep Sharma, OBPP, CO2CRC

Otway Pilot (Australia) Atmospheric MonitoringMonitor CO2 in the atmosphere and define the sources

Flux Tower Lo-Flo*

From Sandeep Sharma, OBPP, CO2CRC

Monitoring Schemes: Monitoring in Mature Context

• Benson study showing that cost of a monitoring scheme, basic or enhanced, is a small fraction of the cost of the whole project.

• Should a large injection then have a large monitoring program?

Techniques to Assure Safe Injection of CO2 Used Currently

• Health and safety procedures for CO2 pipelines, shipping, handling, and storing

• Pre-injection characterization and modeling• Isolation of injectate from Underground Sources of Drinking Water

(USDW) via characterization• Maximum allowable surface injection pressure (MASIP) to prevent

fractures and earthquakes.• Mechanical integrity testing (MIT) of engineered system to prevent

well leakage• Standards for well completion and plug and abandonment in cone

of influence and area of review around injection wells.• Reservoir management; extensive experience in modeling and

measuring location of fluids

Need for Parsimonious Monitoring Program in a Mature Industry

• Standardized, dependable, durable instrumentation, reportable measurements

• Possibility of above-background detection:– Need for a follow-up testing program to assure both

public acceptance and safe operation• Hierarchical approach:

Parameter A

Within acceptable limits:continue

Parameter BNot withinacceptable limits:test

Within acceptable limits:continue

Stop & mitigateNot withinacceptable limits:

Conclusions

• Monitoring approach depends on phase of deployment– Dense monitoring in research phase to

increase confidence– Parsimonious monitoring in commercial phase

• Clarification of the effective but parsimonious strategy to be developed in upcoming projects.