1. 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 : /s 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: /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. ,