2025 Update to the Utah FORGE Native State Numerical Model

Abstract

This paper presents an updated native state numerical model of the Utah FORGE reservoir, incorporating recent pressure, temperature, and stress data acquired through 2024. The model domain extends 6 km by 6 km laterally and 4.5 km vertically, encompassing the granitic reservoir and overlying sedimentary formations. Mesh refinement has been implemented in the well field region to improve resolution of thermal-hydraulic gradients near injection and production intervals. Temperature calibration incorporates updated thermal gradient measurements from multiple wellbores, with particular attention to convective effects in the fractured granite reservoir. The model demonstrates strong agreement with observed downhole temperature profiles. Pressure boundary conditions have been refined based on recent shut-in pressure measurements and hydraulic monitoring data. In-situ stress parameters have been updated to better represent observed geometrically induced anisotropic stress state and its variation with depth, which is critical for predicting fracture orientation during stimulation operations. Key model parameters including rock thermal conductivity, permeability of both fractures and the surrounding reservoir, and bulk reservoir porosity have been recalibrated using circulation test data from 2024. This updated baseline model provides an improved foundation for simulating enhanced geothermal system development at the Utah FORGE site.