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Project Research Application: Geothermal Energy

  • Seismic Imaging, Inversion and Uncertainty Quantification

    The algorithmic workhorse for creating a map of the subsurface from seismic surveys is full waveform inversion. Many fundamental questions remain wide open about it, including how to deal with the lack of convexity in optimization, how to make use of AI to speed it up or supersede it, and how to quantify the uncertainty inherent in its predictions. Among the various projects that the Imaging and Computing group has led over the years, one current topic of great interest is the convergence of AI and uncertainty quantification. We provide the first method for sampling the “epistemic” posterior of a neural network that is consistent with the Bayesian setting. The upshot is for the practitioner to have correct, not arbitrary, error bars on the seismic image.

    Sponsored by: TotalEnergies

    ERL Personnel: Laurent Demanet

  • Modeling Supershear Earthquakes to Forecast Induced Seismicity Hazard

    While the potential for subsurface fluid injection and extraction to trigger earthquakes has long been recognized, the sharp increase in the extent and vigor of injection-induced seismicity calls for much deeper understanding than is currently available. One of the features of some highly destructive earthquakes is their supershear rupture propagation, with velocities faster than the shear wave speed that typically lead to large magnitude events. The intensity and the patterns of strong ground motion for supershear earthquakes have been shown to be inherently different from those of regular (sub-Rayleigh) ones, calling for a need to elucidate the controlling factors behind rupture speed to understand. Fluids fill the pore space of crustal rocks, and pore pressures are essential to understand the stability of geologic fault. However, poro-mechanical effects are often neglected in the analysis and interpretation of earthquake rupture speeds. Here we address the overarching question: what is the role of pore fluids in the generation of supershear earthquakes? We break this down into two fundamental questions: (1) How does pressurization rate from injection impact rupture speeds? (2) Can heterogeneity in frictional properties elicit a transition between rupture regimes (e.g., from slow-slip, to regular earthquake, to supershear earthquake)? We address these fundamental questions through a combination of high-resolution computational modeling and theoretical stability analyses that probe the regime transitions of the coupled fluid/porous solid system.  We anticipate that our results will shed new light in our understanding of supershear earthquakes, paving the way for improved forecasting of earthquake hazards.

    Sponsored by: MIT-Spain UPM Seed Fund

    ERL Personnel: Ruben Juanes (PI)

    Collaborators: Luis Cueto-Felgueroso (co-PI, UPM Spain)

  • Developing Adaptive Traffic Light Systems For Enhanced Geothermal Systems

    Induced seismicity is both a valuable reservoir management tool and a significant challenge, particularly for enhanced geothermal system (EGS) projects. While carefully managed seismic activity can help create and maintain fluid pathways, large earthquakes—such as those that occurred at the Basel and Pohang EGS sites—have raised public concern and highlighted the risks of large-scale deployment.

    Beyond avoiding damaging earthquakes, geothermal operators also aim to keep reservoir stimulation within a defined radius—typically a few hundred meters around the injection well—to maximize heat extraction from a controlled volume of rock. Effective seismic monitoring must therefore balance two key objectives: mitigating the risk of large events and optimizing reservoir performance.

    Our research focuses on developing anadaptive traffic light system that combines seismicity forecasting, ground motion modeling, real-time observations, and machine-learning techniques. This integrated approach is designed to improve seismic hazard management. The system is being tested and calibrated using both natural seismicity and controlled experimental data. 

    Sponsored by: DOE-BES, Utah FORGE

    ERL Personnel: Matej Pec, Hoagy O’Ghaffari, Ulrich Mok, Nori Nakata

  • Electric Stimulation Model Development

    Conventional geothermal energy needs pre-existing fracture networks to conduct heat from rock to water and thence convect heat to surface turbines or other uses. Very few locations, less than 10% of Earth’s land area provide this. Enhanced geothermal systems (“hot dry rock”) can be created anywhere, but require new networks to be fractured. Hydrofracturing uses enormous amounts of pressurized water to fracture rock. Electrofracturing creates an electric plasma channel, essentially subterranean lightning, to fracture rock. Replacing most of the hydrofracturing by electrofracturing promises to save hundreds of millions of liters of water per typical well. This project models the plasma-channel effect by numerically simulating electric-current generation and heating, and nonlinear feedback of voltage and temperature on electric conductivity. It also models the advection of proppant in fracture liquids, and how proppant prevents fracture closure.

    Sponsor: Eden GeoPower, Inc

    ERL Personnel: Aimé Fournier (PI), Laurent Demanet

    Collaborators: Davis Evans, Chunfang Meng, Adrian Moure, Paris Smalls (Eden); Robert Egert, Wencheng Jin, Vuong Van Pham, Ming Yang, Chunhui Zhao (Idaho National Laboratory)

  • Coupled flow-geomechanical models applied to assess earthquake triggering in tectonically active regions – The Los Angeles basin, CA

    Earthquakes caused by human activities are a growing societal concern affecting hydrocarbon and geothermal energy production, gas storage, and subsurface carbon sequestration efforts in the Unites States and throughout the world. Distinguishing between tectonic and induced earthquakes in tectonically active regions is extremely challenging. Moreover, induced seismicity in these regions pose greater risks, as human activities may trigger larger and more destructive earthquakes. Our project is developing state-of-the-art, physics-based models to investigate how nearly a century of production and waste-water injection in hydrocarbon fields of the Los Angeles basin, California, have impacted the stability of faults in the area. These models consider stress changes on faults caused both by tectonic and anthropogenic processes, thus helping to distinguish between tectonic and induced events. The project will advance methodologies to investigate and manage triggered seismicity in Los Angeles and other tectonically active regions.

    Sponsored by: NSF Geology and Geophysics

    ERL Personnel: Ruben Juanes (PI)

    Collaborators: John Shaw (PI, Harvard), Lluis Salo-Salgado (Harvard)