Recent Advances in Well-Based Monitoring of CO2 Sequestration Barry Freifeld1, Tom Daley1, Susan Hovorka2, and Sandeep Sharma3 1Lawrence Berkeley National Laboratory 2Bureau of Economic Geology, The University of Texas at Austin 3CO2CRC, Schlumberger Carbon Services ABSTRACT FRIO CONTINUOUS ACTIVE SOURCE SEISMIC MONITORING New instruments and methodologies have been developed to improve monitoring CO2 storage in the subsurface. The U-tube geochemical sampling system facilitates acquisition of uncontaminated aliquots of multiphase fluids from deep boreholes. The Continuous Source Seismic Monitoring system permits imaging of the moving plume between wells. The Frio Brine Pilot and CO2CRC Otway Project have provided testing grounds for these tools under a wide range of conditions. To maximize the information obtained from each wellbore we typically deploy multi-functional integrated monitoring completions to provide a comprehensive set of data to evaluate subsurface conditions. Below Packer Above Packer FRIO BRINE PILOT Injection interval: 24-m-thick, mineralogically complex Oligocene reworked fluvial sandstone Porosity 35%, Permeability 2.3 Darcys 6m perforated zone Seals  numerous thick shales, small fault block Depth 1,500 m Brine-rock system, no free-phase hydrocarbons 143 bar, 63 degrees C, supercritical CO2 . CO2CRC OTWAY PROJECT, VICTORIA, AUSTRALIA U-TUBE FLUID SAMPLING 5000 ft CO2 Storage in a depleted gas reservoir. Injection started April 2008 and concluded August 2009 with ~65,000 tonnes gas injected. Naylor-1 Monitoring Completion: Gas-lift line for borehole purging Pneumatic packer 3-level U-tube geochemical samplers 21 Geophones / 3 Hydrophones 3 levels 3 component geophones 9 vertical geophones for VSP In reservoir phones for high resolution travel time 2 Pressure/Temperature Sensors WVSP and HRTT data is obtained using dynamite shots to image the CO2 plume 1 year of planning, 11 control lines & 4 days of 24 hour operations to install the monitoring equipment in Naylor-1 REFERENCES Daley, T.M., Myer, L.R., Peterson, J.E., Majer, E.L., Hoversten, G.M., 2007a, Time-lapse crosswell seismic and VSP monitoring of injected CO2 in a brine aquifer, Environmental Geology, DOI :10.1007/s00254-007-0943-z. Freifeld, B.M., Trautz, R.C., Yousif K.K., Phelps, T.J., Myer, L.R., Hovorka, S.D., and Collins, D., The U-Tube: A novel system for acquiring borehole fluid samples from a deep geologic CO2 sequestration experiment, J. Geophys. Res., 110, B10203, doi:10.1029/2005JB003735, 2005. ACKNOWLEDGMENTS Samples collected using high pressure N2 gas drive Large volume ~50 L Maintains sample integrity – no degassing during recovery High purity – no contamination from air Collection of multiphase fluids This work was supported by the National Energy Research Laboratory, US Department of Energy, Office of Fossil Energy, under DOE Contract Number DE-AC02-05CH11231 and by the Australian Cooperative Research Centre for Greenhouse Gas Technologies. bmfreifeld@lbl.gov, tmdaley@lbl.gov , sharma2@slb.edu, susan.hovorka@beg.utexas.edu