Imaging and Monitoring Enhanced Geothermal Systems
As facilitated by my joint appointment with PNNL and working relationship with several other lab-based groups, my students frequently spend summers working on geothermal system imaging problems namely to study fracture propagation and changes in scattering structures inherent in fluid injection sites. Responding to the urgency of the need for future renewal energy infrastructure, DOE initiatives like GENESIS Mission have clearly highlighted the need for rapid development of both geothermal energy production and, in tandem, imaging and monitoring of these systems.
Several student-led collaborations over the last several years (and this summer) are seeking to develop next generations methods to exploit both local induced seismicity and, where available, repeated man-made seismicity to detect subtle changes in scattering.
We developed for instance a novel algorithm seeking to invert small decorrelations in repeating coda for fracture plane structures through the imposition of a parametric intermediary and radiative transfer scattering kernels, and we are applying the method to the EGS Collab dataset collected by PNNL (https://www.energy.gov/hgeo/geothermal/egs-collab). We are furthermore leveraging full 3D radiative transfer simulations (as developed for Erebus volcano!) to study azimuthal variations in scattering in fractured bodies, as well as leveraging direct inversions of simplified isotropic scattering approximations for comparison at full scale sites (collaboration with LBNL).
We are currently on our third iteration of the NSF/DOE Geothermal Intern program (https://www.energy.gov/hgeo/geothermal/nsf-intern-program) and anticipate continued participation in the program in years to come.
Variation of firn resonance modes as impacted by winds and steady state conditions. Right panel: Spectrogram of resonances modified by passing storms.