Ambient Seismic Imaging Technology for Low Cost and Effective Geothermal Resource Exploration, Development, and Management

Ambient Seismic Imaging (ASI) technology uses seismic emission tomography methods and passively listens to vibrations due to stress-change-induced fluid-rock interactions. These interactions are episodically created by the earth’s flux of stresses due to tectonic, fluid flow activities, and gravitational forces. Natural rock permeability-associated vibration episodes are common over periods of many minutes. Comparable and larger stresses can also be created during fluid withdrawals and reinjections. With ASI, we can identify and map permeability. In potential and existing geothermal sites, we propose to use ASI technology to significantly lower costs and provide increased accuracy and more robust techniques for characterizing permeability features and fluid flow, thereby lowering risk. AltaRock Energy and Quaise Energy are companies supporting our approach with access, data, and cooperation at the Newberry geothermal field in Oregon. We propose to advance geothermal development by adapting ASI for mapping Newberry’s permeability architecture. Our focus will be on the measurement methods, network designs, and deployment campaigns that underpin the success of ASI technology at this type of site. Of note, in addition to its natural background ASI signals, we anticipate even larger ones when AltaRock injects cold water to stimulate a new reservoir. Geothermal energy is predicted to play a critical role in energy transition. With reduced costs and improved technology, it is expected that geothermal power generation will increase nearly 26-fold from today. With its success, ASI technology can increase the chances for achieving this goal for a broad set of stakeholders: from the public that wants to deal with climate change, to industries, utilities and developers that want to implement geothermal energy—and would be our customers. Geothermal projects face significant risks for reservoir identification, characterization, and management. Developers need to ensure project feasibility and integrity, improve targeting of permeability structures, and control induced seismicity. ASI contrasts with status quo reflection seismology’s use of induced earthquakes and controlled sources, both which add cost and complexity. Reflection seismology is suboptimal for imaging permeability structure and fluid flow. ASI has overcome these limits, but not in geothermal applications, which is the target of our R&D.