EESA will lead one of those projects, with David Alumbaugh as lead PI, and will participate in a second FORGE-sponsored project led by EGD faculty scientist Jonathan Ajo-Franklin of Rice University, with Julia Correa as LBNL PI.
The research will explore enhanced geothermal systems (EGS) technologies that are different from conventional geothermal resources which, like The Geysers in northern California, are naturally occurring and geographically limited due to the need for underground heat and fluids. These man-made geothermal reservoirs could be engineered in most parts of the country to increase geothermal energy production and potentially transform the domestic energy portfolio. Although the U.S. leads the world in installed geothermal capacity, power generation from conventional geothermal systems accounts for just two percent of the country’s renewable energy portfolio. The DOE GeoVision study indicates that advances in technology will permit EGS to provide a significant contribution to renewable power generation in the U.S. over the next few decades.
EESA has broad expertise in EGS research, namely as lead of EGS Collab, an effort involving nine other DOE national labs and eight universities focused on gaining advanced understanding of rock fractures through field experimentation.
The two projects led by Alumbaugh and Ajo-Franklin both encompass one of the five topics designated by GTO and FORGE in their selection process: Field-scale characterization of reservoir stimulation and evolution over time, including thermal, hydrological mechanical, and chemical (THMC) effects.
The project that Berkeley Lab will lead is entitled, “Joint Electromagnetic/Seismic/InSAR Imaging of Spatial-Temporal Fracture Growth and Estimation of Physical Fracture Properties During EGS Resource Development.” The objective of this project is to estimate spatiotemporal fracture growth and fracture properties during the engineered geothermal system (EGS) experiment at the Utah FORGE site. To that effect, LBNL scientists along with researchers at the Colorado School of Mines and Array Information Technologies will use electromagnetic, seismic, and Interferometric Synthetic Aperture Radar (InSAR) data in a novel joint inversion scheme that includes coupled temperature, hydrological, mechanical, and chemical (THMC) parameter estimation.
David Alumbaugh said, “This project leverages Berkeley Lab’s leadership and expertise in acquiring and interpreting seismic and electromagnetic geophysical measurements with InSAR data analysis, along with recent advances and developments in computationally demanding THMC numerical modeling. The ultimate goal is to provide the FORGE site operators with specific information about the reservoir fracturing processes including fracture location and orientation, and the volume of the reservoir that has been stimulated.”
The second project, led by Ajo-Franklin at Rice University and Correa as Berkeley Lab PI, is entitled “Fiber-Optic Geophysical Monitoring Of Reservoir Evolution at the FORGE Milford Site.” The project aims to apply continuous monitoring using an array of sensors, including fiber-optic strain sensors and permanent seismic sources, to understand the flowing fracture network. It will involve mapping the zones of mechanical stimulation, resolving the locations of newly formed fractures, as well as mapping the zones of flowing fractures. Continuous monitoring can be an important asset for EGS projects as it could help improve the location of new target injection and production wells, as well as plan stimulation activities, leading to optimized thermal recovery.
Correa said, “This project gives us the opportunity to apply EESA’s unique expertise in distributed fiber-optic sensing and permanent sources to an area that hasn’t really seen a substantial industry application of geophysical techniques.
“By improving our monitoring capabilities of EGS projects, we can better understand the fracture network affecting long-term geothermal energy production.”
