Paper No. 9
Presentation Time: 10:35 AM
LEVERAGING THERMAL-HYDROLOGICAL SCIENCE AND TECHNOLOGY AT YUCCA MOUNTAIN TO ACTIVE MANAGEMENT OF INTEGRATED GEOTHERMAL CO2-STORAGE RESERVOIRS
BUSCHECK, Thomas A., Atmospheric, Earth, and Energy Division, Lawrence Livermore National Laboratory, P.O. Box 808, L-184, Livermore, CA 94550, SUN, Yunwei, Atmospheric, Earth, and Energy Division, Lawrence Livermore National Laboratory, P. O. Box 808, L-184, Livermore, CA 94551, HAO, Yue, Atmospheric, Earth, and Energy Division, Lawrence Livermore National Laboratory, P.O. Box 808, L-184, Livermore, CA 94551 and BLINK, James A., Global Security E Program, Lawrence Livermore National Laboratory, P.O. Box 808, L-090, Livermore, CA 94550, buscheck1@llnl.gov
Geothermal energy and CO
2 capture and sequestration (CCS) in deep geological formations can play increasingly important roles in reducing CO
2 emissions to the atmosphere and thereby mitigate global climate change. Nuclear power, also a contributor to CO
2 reductions, requires safe and reliable radioactive waste management, which in turn requires sound thermal management of heat-generating waste. The Yucca Mountain Project supported major science and technology advances in unsaturated-zone thermal hydrology, including the development of flow and reactive transport codes, such as TOUGH2, FEHM, and NUFT, as well as modeling approaches, such as the Multiscale Thermohydrologic Model. Resulting validated models were used to support the design of the repository, based on thermal-management principles, as well as support the total system performance assessment. This work is currently being leveraged in science and technology development of geothermal and CCS systems.
For industrial-scale CO2 injection in saline formations, pressure buildup can be the limiting factor in storage capacity and security, while geothermal energy production is often limited by pressure depletion. These two complementary systems can be integrated synergistically, with CO2 injection providing pressure support to maintain the productivity of geothermal wells, while brine production provides pressure relief and improved injectivity for CO2 injection wells. Active CO2 Reservoir Management (ACRM) combines brine production with CO2 injection to relieve pressure buildup, increase injectivity, manipulate CO2 migration, constrain brine leakage, and enable beneficial utilization of produced brine. Useful products include freshwater, cooling water, make-up water for oil, gas, and geothermal reservoir operations, and electricity generated from geothermal energy. In addition to reducing costs and risks associated with CO2 storage, ACRM minimizes interactions with neighboring subsurface activities, which reduces pore-space competition and allows independent assessment and permitting of neighboring subsurface operations. These benefits can help achieve public acceptance.
This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
