Susan Hovorka Gulf Coast Carbon Center Bureau of Economic Geology Jackson School of Geosciences

1. Monitoring Geologic Sequestration: Transition from Demonstration to Commercial Environments: Questions for Discussion Susan Hovorka Gulf Coast Carbon Center Bureau of Economic Geology Jackson School of Geosciences The University of Texas at Austin Presented to RWG of SECARB January 31, 2007

2. 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 Atmosphere Biosphere Vadose zone & soil Aquifer and USDW Seal Monitoring Zone Seal CO2 plume

3. A balanced and phased approach to permitting and monitoring Balanced Phased Adequate rigor to assure that early programs do not fail Not too restrictive: encourage early entry into CCS – gain experience; Learn by doing Early (now) Mature (As defined by time? Or by injection volume?) Adequately rigorous to assure performance and public acceptance Standardized, parsimonious

4. The Question of Balance: How Much is Enough? Site Characterization Mitigation/ Corrective Action Public Participation Monitoring 3-D seismic Redundant injection sites/ pipeline system 4-D seismic Litigation Test program Multiple zones multiple tools Public comment & response mechanisms Response if non-compliance occurs Multiple in-zone wells Less More Selected tools Selected zones Public hearings MIT surface pressure injected volumes Stop injection Regional + injection well Public information Examples, not an exhaustive list

5. 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

6. TexasFutureGen Texas Class I The Question of Balance: How Much is Enough? Site Characterization Mitigation/ Corrective Action Public Participation Monitoring 3-D seismic Redundant injection sites/ pipeline system 4-D seismic Litigation Test program Multiple zones multiple tools Public comment & response mechanisms Response if non-compliance occurs Multiple in-zone wells Less More Selected tools selected zones Public hearings MIT surface pressure injected volumes Stop injection Regional + injection well Public information

7. 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 plume Elevated pressure

8. 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 Atmosphere Biosphere Vadose zone & soil Aquifer and USDW Seal Monitoring Zone Seal CO2 plume

9. Aquifer wells (4) Downhole P&T Frio 1 Pilot: Cross-Comparison of Multiple Types of Measurements Determine the subsurface distribution of injected CO2 using diverse monitoring technologies Gas wells Access tubes, gas sampling Downhole sampling U-tube Gas lift Wireline logging Radial VSP Cross well Seismic, EM Tracers

10. RST logs Tubing-hung seismic source and hydrophones Frio 2 Monitoring Design:Test of buoyancy, residual saturation, dissolution Injection Well Observation Well U-tubes 50 m Packers Downhole P and T Frio “Blue” Sandstone 15m thick

11. Otway Pilot (Australia) Time Structure Map Injection well From Sandeep Sharma, OBPP, CO2CRC

12. 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

13. 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 From Sandeep Sharma, OBPP, CO2CRC

14. CO2 ppm (vol) 100 1000 10000 100000 -5 range Otway natural gas average Air -10 background deep subsurface d13C CO2 (o/oo) -15 organic matter 'decomposition' -20 Otway Pilot area Cape Grim air 2001 Otway air 2005 -25 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 From Sandeep Sharma, OBPP, CO2CRC

15. Otway Pilot (Australia) Atmospheric Monitoring Monitor CO2 in the atmosphere and define the sources Flux Tower Lo-Flo* From Sandeep Sharma, OBPP, CO2CRC

16. 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?

17. 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

18. 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: Not within acceptable limits: Parameter A Not within acceptable limits: test Parameter B Stop & mitigate Within acceptable limits: continue Within acceptable limits: continue

19. 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.