Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 G. Michael Hoversten Sally Benson Erika Gasperikova Lawrence Berkeley National Laboratory Monitoring Protocols

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03Introduction Sequestration examplesSequestration examples –Sleipner –Numerical simulation Project phases and monitoringProject phases and monitoring Key Monitoring elementsKey Monitoring elements –Remote sensing –Surface measurements –Geophysics Monitoring Purpose & methodsMonitoring Purpose & methods ConclusionsConclusions

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Sleipner (North Sea) CO 2 moves vertically by buoyancy forces –100m in 5 years at Sleipner (probably within 1 year) Below ~ 800 m CO 2 is liquid state –Density ~ 20% less than brine Above ~ 800 m CO 2 is in gas state –Density ~ 99% less than brine Critical FactorsCritical Factors –Pressure gradient –Permeability –Residual gas saturation –Density contrast

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Numerical Simulation Residual gas saturation is a factor controlling transport –This expresses how much CO 2 stays behind in the pore space as fluid movement occurs CO 2 Dissolves into brine –On 1000 s year time scale CO 2 rich water sinks due to increased density

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Project Phases & Monitoring Pre-operationPre-operation –Characterization of the reservoir –All background levels of CO 2 Air, water, soilAir, water, soil OperationsOperations –Most vigorous monitoring Reservoir & seal performanceReservoir & seal performance ClosureClosure –Surface facilities removed, wells plugged –Confirmatory period to demonstrate that the storage project is performing as expected Post ClosurePost Closure –Monitoring ends except for On-going low level leakageOn-going low level leakage If new information is needed or legal disputesIf new information is needed or legal disputes

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Project Phases & Monitoring

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Key Monitoring elements Airborne monitoringAirborne monitoring –LIDAR (light detection and range-finding) a scanning airborne laser, and DIAL (differential absorption LIDAR) –Hyper-spectral imaging Specific habitats can be identified by their spectral signatureSpecific habitats can be identified by their spectral signature CO 2 stress on vegetation shows up as changes in plants reflectivity at certain wavelengthsCO 2 stress on vegetation shows up as changes in plants reflectivity at certain wavelengths Surface Detection & QuantificationSurface Detection & Quantification –Infrared gas analyzers (IRGA) Well headsWell heads Basements & depressionsBasements & depressions –Soil sampling Geochemical MonitoringGeochemical Monitoring –Impact to ground water (analyzed for major ions) –Chemical tracers (interaction with the reservoir) Image after Pickles 2003

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Key Monitoring elements Well head injection rate & pressureWell head injection rate & pressure –Over pressuring the reservoir can lead to hydraulic fracturing Loss of seal integrityLoss of seal integrity Well failureWell failure Geophysical DetectionGeophysical Detection –Mapping spatial changes as injection proceeds –Anomalous event indicator LeaksLeaks Unforeseen transport paths within formationUnforeseen transport paths within formation Geophysical QuantificationGeophysical Quantification –How much CO 2 is present at a given location Process control to optimize S CO2Process control to optimize S CO2 How accurate are flow model predictions?How accurate are flow model predictions? –Dependent on many more assumptions and knowledge than detection for success

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Key Monitoring elements LeaksLeaks –Seismic is the best way to see leaking CO 2 EARLY Large velocity change with small % CO 2 above ~ 1200mLarge velocity change with small % CO 2 above ~ 1200m Very thin (5m) accumulations will show up on a seismic sectionVery thin (5m) accumulations will show up on a seismic section –Assumption: the CO 2 will move out laterally at some point on its upward migration Vertical CO 2 zones are much harder to seeVertical CO 2 zones are much harder to see

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Monitoring Purpose & Methods

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03 Later project Protocols Well head sensorsWell head sensors Airborne imageryAirborne imagery Periodic water well samplingPeriodic water well sampling Subsurface Detection onlySubsurface Detection only –Seismic at 1 year –Micro-seismicity for 1 or 2 years Continuation depends on activityContinuation depends on activity –Seismic every 5 years for leak detection –Gravity & possible EM every few years Lower cost & resolutionLower cost & resolution –Surface Deformation Permanent Scatter Technique (enhanced In-SAR)Permanent Scatter Technique (enhanced In-SAR) –$100 / raw data –mm resolution

Earth Science Division E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY B ERKELEY L AB 9/30/03Conclusions Early projects will be test bedsEarly projects will be test beds Monitoring Protocols will have to be site specificMonitoring Protocols will have to be site specific –Site characterization is critical for proper design Research is ongoing into sensitivity levels and improvements of all monitoring systemsResearch is ongoing into sensitivity levels and improvements of all monitoring systems Subsurface geophysics will dominate costsSubsurface geophysics will dominate costs –Seismic is highest cost, highest resolution, best early warning of leak in time to prevent CO 2 reaching the surface Subsurface monitoring with petroleum heritage is the most developedSubsurface monitoring with petroleum heritage is the most developed