MODELING FAULT-RELATED DEFORMATION AND IMPLICATIONS FOR GEOTHERMAL ENERGY POTENTIAL

Geothermal energy is a growing clean energy resource, but limited identification of productive geothermal systems minimizes utilization. However, previous research identifies settings that produce the fracture densities necessary for subsurface fluid flow and thus geothermal production. Normal fault zones are promising geothermal locations, especially between fault segments where interacting stress fields promote deformation. Normal faulting is prevalent in the Basin and Range Province, making it a prime location for exploration.

To better understand geothermal potential in normal fault zones, we collected field-based structural data along the segmented Sevier normal fault in Utah. With this data to validate our computer modeling, we constructed 3D models in the Fault Response Modeling module of MOVE 2022 (by Petex). Our models include a single 6-km long normal fault and a segmented two fault system overlapping by 1 km. Faults dip 70 degrees to the west and cut model stratigraphy with physical properties consistent with the Jurassic Navajo Sandstone that dominates exposure in the study area. With these models, we documented throw, maximum coulomb shear stress, maximum strain, strain dilation, fracture orientation, and fracture intensity, varying observation depths and slip between models to examine impacts on geothermal potential.

Though we noted differences in stress, strain, and fracturing across models, fracture intensity was consistently high near the fault and between interacting fault tips. Fracturing also shifted from high within the hanging wall to high in the footwall as fault depth increased. These results indicate that potential geothermal locations likely lie near normal faults, but may vary in position relative to the fault with depth. Furthermore, results suggest high geothermal potential in transfer zones within segmented normal fault systems like the Sevier, provided that heat flow can sustain energy production.

In future models, we will investigate the implications that different fault propagation models (constant length vs. propagating) hold for geothermal potential in extensional settings. Though 3D computer modeling cannot perfectly locate geothermal energy systems, its implementation could help identify regions for targeted exploration, leading to greater production.