Storage in Subsurface Pore Space: Monitoring CO 2 Storage

Workshop on Geological Capture and Sequestration of Carbon Nov. 28, 2017 Stanford University Storage in Subsurface Pore Space: Monitoring CO 2 Storage Thomas M. (Tom) Daley Lawrence Berkeley National Laboratory

Outline Goals of Monitoring Types of Monitoring direct/indirect, qualitative/quantitative Brief Status of Seismic Monitoring technology Issues with quantitative analysis Need for Integrating Multi Physics Issues and R&D needs

Monitoring: What, When, Where, Why? Choosing Monitoring Need to have goals to guide decisions! When and Why to Monitoring after Mathieson et al., 2010 after Peters 2007

Goals of Monitoring Performance Assurance Injection and growth of plume are progressing as expected (modeled) Expect quantitative monitoring to compare to models Regulatory Compliance Varies with location, e.g. US EPA requires systems that detect leakage of CO 2 from either the containment reservoir or away from the storage site Risk Reduction Will overlap with Performance Assurance monitoring understanding risk driven monitoring uncertainty will require dedicated experiments to probe and test monitoring of actual leakage scenarios. (Harbert, et al., 2016) Public Assurance Private water wells, induced seismicity, atmospheric sampling

Types of Monitoring Site Characterization vs Monitoring Characterization typically implies a static snapshot of properties, but needs to be an iterative process including monitoring to capture dynamics Optimal monitoring design needs accurate characterization, but changes can be detected without accurate static characterization Direct and Indirect Monitoring Direct => Pressure, geochemical sampling Key to confirming interpretations; Limited to specific locations, typically in boreholes Indirect => Seismic reflection; ground deformation; electrical conductivity Most cost effective; Can cover large areas, typically with decreasing resolution at distance Quantitative and Qualitative Monitoring Quantitative => e.g. CO2 mass in a given volume Qualitative => e.g. detection of CO 2 at unknown saturation Need to understand differences when discussing/designing monitoring

Seismic Monitoring Seismic monitoring is the workhorse. Advanced technology from O&G industry Quantitative analysis for CO2 saturation is still developing and problematic. Basic Seismic Rock Physics We measure wave velocity (Vp), we want gas saturation (Sg); In conventional analysis they are linked by the bulk modulus for saturated rock (K sat ), rock matrix (K*), matrix minerals (K 0 ) combined fluid ( K fl ), along with porosity Φ. Gassmann Substitution: V P > K sat ; K sat > K fl ; K fl > S g (e.g. Smith, et al, 2003) Many assumptions here including static matrix properties, uniform fluid mixing, homoenegenity, no rock fluid interaction

Seismic Monitoring can be very sensitive, but Frio Project had too large of response why? Daley, et al., 2006

Seismic Issue: Uncertainty in Fluid Mixing V p (m/s) 0 50 100 150 200 250 300 350 400 450 500 0 0.2 0.4 0.6 0.8 1 CO 2 Saturation (fraction) Daley, et al., 2011 WDO, 15 cm patch WDO, 2.5 cm patch Gassmann + Reuss Gassmann + Voigt BGH [A] As we increase frequency to improve resolution, the rock physics becomes more uncertain Uniform vs Patchy Saturation (wavelength dependent) Also sensitive to P T conditions, brine properties, anisotropy, dissolution into brine and any other gas saturation (e.g. CH 4 )

Issue: Geochemical Alteration Mainly issue in carbonates, but also silicic rocks Two main changes are involved: porosity enhancement due to dissolution, and loss of granular microstructure Time Lapse CT Scan Of Fountainebleau sandstone From Vanorio, et al., 2011.

Frio Frame Change Can Explain Data Frame Cementation Change inferred from Seismic data, invalidates Gassmann assumption Need to consider geochemical alteration and, Need to have Multi Physics monitoring data: both P wave and S wave to resove change Frio Cementation Models Change in Vp at Frio increased by geochemistry Matrix Cement Alteration (0.1 to 0.01%) Al Hosni, et al., 2015

R&D Needs Field Experiments Larger Scale Gigatonne? Integrate multi scale field measurements Test leakage detection and mitigation Understand Importance/Impact of monitoring wells Cost/Benefit of monitoring wells how many and where? Multi physics to improve quantification Active source seismic is key tool, but has quantification limits and issues Uncertain rock physics Geochemical impacts

Need Multiple Scales of Investigation Scale of Investigation Regional ~10 to 10 4 m Local ~10-2 to 10 2 m Lab ~10-4 to 10-1 m Well Logs Core Tests Borehole Seismic VSP, Crosswell Need Boreholes Satellite (InSAR) Surface Seismic ~10-3 to 1 m ~10-1 to 10 m ~10 to 10 3 m Approximate Spatial Resolution Boreholes are key for direct monitoring, especially pressure (a high value parameter)

Need Multi Physics: Example Seismic and EM Seismic alone has uncertainty at high CO2 saturation and uncertainty in rock physics interpretation EM (conductivity) has strong sensitivity at all saturations and a single rock physics model (Archie s relation) and should complement seismic for estimating saturation within plume Ideally combine seismic, EM and flow models in joint inversion for CO2 Boundary And Leakage Detection Plume Body Monitoring Saturation from Archie s Relation Xue, et al., 2009

3 Specific Field Experiments Needed Shallow Groundwater Gas and Dissolved CO 2 detection Intermediate Depth Leakage, Gas Phase detection Deep Fault/Fracture Flow Supercritical flow in fractures Induced seismicity Need to test mitigation in all three Shallow has limited testing (ZERT, Plant Daniel); Intermediate has one new test (CaMI); No deep fracture/fault tests (one planned at Otway; one unintended at In Salah)

Importance of Fault/Fracture Leakage Field Studies Field projects to date has demonstrated safe storage, but we need to study/understand leakage pathways Faults and fracture zones have potentially high flow Recent work shows uncertain link between fault permeability change and pressure (for brine) Fault Leakage can occur below the Critical Stress State Permeability change may occur before or without reactivation. Results from an in situ fault reactivation experiment, Guglielmi, et al, 2017 Permeability depends on Stress + Local Strain or Strain Rate Permeability variations associated with fault reactivation in a claystone formation (Jeanne, et al, in review). In Salah Fracture Zone Zhang, et al, 2015

Summary Need to understand the goals of monitoring to drive R&D Need to understand the types of monitoring, don t compare apples to oranges direct/indirect, qualitative/quantitative Seismic is key technology but need to consider geochemical impacts to improve quantification Field Experiments at Larger Scale Gigatonne? Need to test leakage and mitigation scenarios Need indirect, quantitative monitoring Understand Importance/Impact of monitoring wells Key for direct monitoring, especially pressure Need Multi physics to improve quantification Use/integrate Shear waves, electrical/em measurements, pressure, deformation And a final comment: How often to monitor continuous? O&G Industry moving to permanent reservoir monitoring (PRM) New technology (e.g. fiber optics) is decreasing cost of permanent monitoring

Appendix: Recent Industry R&D Review The workshop had a general discussion of status and R&D topics for geophysical monitoring of CO 2. Examples include: Are we ready for gigatonne scale up?, How do we bring monitoring costs down?, Can we use shallow leakage experiments to test mitigation? and a discussion of induced seismicity issues. Look at use of controlled leakage sites for how to stop leakage Evaluate detection thresholds Summarize detection levels from field experiments Use of multi physics, how to combine Using joint inversion, multiple approaches to improve quantification Need more measurements, how to make them less expensive Use of permanent buried systems, what is best use Move to integrating monitoring with decision making, for efficiency Uncertainty quantification, rock physics at field scale, spatial and temporal variability Need for lab measurements, especially electrical properties Consider change in properties due to contaminants in CO2 stream or subsurface, can they be used as tracer Dissolution of co2, need geochemical research on lifetime of co2, does shallow dissolution add to trapping Pressure monitoring above zone, monitoring of secondary storage How do we assess value of information, more work on assessing value of monitoring techniques Fault reactivation and understanding process and how to monitor, what is flow mechanism in fault fractures Induced seismicity with large scale injection How to measure bicarbonate in water use of fiber The general feeling is that current technologies exist for CO 2 injection characterization and monitoring, although technical and economic challenges remain. Permanent buried seismic arrays should help the industry to reach the required levels of accuracy. From Verliac, et al, First Brea, in press. Workshop Summary Questions and Important R&D Topics Are we ready for Gigatonne scale up? How do we bring monitoring costs down? Have we demonstrated minimum CO2 visible/detectable? Why did some projects fail? Improve seismic technology: Can DAS replace geophones, for VSP, MEQ, surface? Need uncertainty quantification for saturation estimates? Gravity monitoring may be good for leakage (higher density contrast and shallower) Discussion: Leakage: Affects on green house gas storage; Question: what do we do with a leak? Can we use shallow leakage experiments to test mitigation? Discussion: Impacts of Induced seismicity Question: Can seismic separate pressure and saturation? How, and what data is needed? Question: Should MEQ monitoring be required? Question: on use of nanoparticles Question: How to best use InSAR other information needed?

References Al Hosni, M Vialle, S., Gurevich, B., Daley, T. M., 2016, Estimation Of Rock Frame Weakening Using Time Lapse Crosswell: The Frio Brine Pilot Project, Geophysics, 81, B235 B245, DOI: 10.1190/GEO2015 0684.1 Börner, J.H., Herdegen, V., Repke, J. U. and Spitzer, K., The electrical conductivity of CO2 bearing pore waters at elevated pressure and temperature: A laboratory study and its implications in CO2 storage monitoring and leakage detection, 2015, Geophys. J. Int., 203 Daley, T. M., L. Myer, J. E. Peterson, E. L. Majer, and G. M. Hoversten, 2008, Time lapse crosswell seismic and VSP monitoring of injected CO2 in a brine aquifer: Environmental Geology, 54, 1657 1665, doi: 10.1007/ s00254 007 0943 z. Daley, Thomas M., Jonathan B. Ajo Franklin, Christine Doughty, (2011). Constraining the reservoir model of an injected CO 2 plume with crosswell CASSM at the Frio II brine pilot, International Journal of Greenhouse Gas Control, 5, pp. 1022 1030, DOI information: 10.1016/j.ijggc.2011.03.002 Jeanne, P., Y.Guglielmi, J.Rutqvist, C.Nussbaum and J. Birkholzer (in review) Permeability variations associated with fault reactivation in a claystone formation Investigated by field experiments and numerical simulations, In review at Journal of Geophysical Research. Guglielmi, Y., J.Birkholzer, J.Rutqvist, P.Jeanne, C.Nussbaum (2017) Can fault leakage occur before or without reactivation. Results from an in situ fault reactivation experiment at Mt Terri. Energy Procedia 114, 3167 3174. Harbert, W., T M. Daley, G Bromhal, C Sullivan, and L Huang, 2016, Progress in monitoring strategies for risk reduction in geologic CO 2 storage, International Journal of Greenhouse Gas Control, pp. 260 275. DOI: 10.1016/j.ijggc.2016.05.007 Mathieson, A., Midgley, J., Dodds, K., Wright, I., Ringrose, P., and Saoul, N., 2010. CO 2 sequestration monitoring and verification technologies applied at Krechba, Algeria. Leading Edge 29 (2), 216 222. Nakagawa, Seiji, Timothy J. Kneafsey, Thomas M. Daley, Barry M. Freifeld, and Emily V. Rees, 2013, Laboratory seismic monitoring of supercritical CO2 flooding in sandstone cores using the Split Hopkinson Resonant Bar technique with concurrent x ray CT imaging, Geophysical Prospecting, 61, 254 269. Peters, D., 2007. CO 2 geological storage methodology and risk management process. NHA Hydrogen Conference March 20, 2007. Smith, T. M., Sondergeld, C.H., and Rai, C. S., (2003). Gassmann fluid substitutions: A Tutorial, Geophysics, 68, p430 440. Vanorio, T., G. Mavko, S. Vialle, and K. Spratt, (2010). The rock physics basis for 4D seismic monitoring of CO 2 fate: Are we there yet?: The Leading Edge, 29, 156 162. Vanorio, T., Nur, A., and Ebert Y., 2011, Rock physics analysis and time lapse rock imaging of geochemical effects due to the injection of CO2 into reservoir rocks, GEOPHYSICS. VOL. 76, 5, 10.1190/GEO2010 0390.1 Xue, Z.; J. Kim, S. Mito and K. Kitamura, T. Matsuoka, 2009, Detecting and Monitoring CO2 with P wave Velocity and Resistivity from Both Laboratory and Field Scales, SPE International Conference on CO2 Capture, Storage, and Utilization, SPE 126885. Zhang, R., Vasco, D., Daley, T.M., 2015, Characterization of a fracture zone using seismic attributes at the InSalah CO2 storage project, Interpretation, SM37 46. DOI:10.1190/INT 2014 0141.1.

Issue: Geochemical Alteration Geochemical alteration can be first order affect, especially on carbonates Invalidates Gassmann assumption of constant frame properties and constant porosity With multi physics data (e.g. P and S wave seismic data) we can reduce uncertainty P Wave S Wave Vanorio, et al., 2010

Need Laboratory Calibration of Seismic Response Difference between measured data and Gassmann model attributed to the softening of the mineral grains and grain contacts. Compressional Shear Nakagawa, et al, 2013. Tuscaloosa Formation, Cranfield