Seismic Monitoring for the Multi-Month Circulation at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE)

Abstract

The Utah Frontier Observatory for Research in Geothermal Energy (FORGE) is a U. S. Department of Energy funded, field-scale laboratory dedicated to developing and testing technologies for the commercialization of Enhanced Geothermal Systems (EGS). Past operational hydraulic fracturing activities at Utah FORGE have included stimulations in 2019, 2022, and 2024 and a month-long circulation test in 2024. Each of these activities has been seismically monitored. Seismic monitoring is focused on both implementation of the Traffic Light System and imaging microseismic fractures in the reservoir. Seismic monitoring has evolved from operation to operation with the advent of new tools and advances in seismic processing. For the planned 2026 three-plus month-long circulation test, we propose to integrate data from deep borehole DAS, geophones in three deep boreholes, and data from geophones in three shallow (~300 m) boreholes to generate a real-time catalog. Separately, we will integrate data from the surface and shallow posthole and borehole stations into a machine-learning based algorithm to build an independent catalog. This catalog together with regional seismic monitoring efforts will be used to implement the Utah FORGE Traffic Light System and together with the hydraulic pumping data will be used to test an Adaptive Traffic Light System. We will also deploy a temporary geophone network. The geophone network will build on past temporary geophone experiments and deploy a mix of patches and single element geophones to enhance post-processing efforts.