BASIN MODELING OF MESOZOIC SILICICLASTIC STRATA APPLIED TO SEDIMENTARY GEOTHERMAL EXPLORATION, IRON COUNTY, UT

Extensional sedimentary basins in the Basin and Range Province hold significant potential for increasing baseload power generation in the Intermountain West, thereby supporting a lower-carbon future for urban and rural communities. The Escalante Basin in Iron County, Utah, is the focus of ongoing research into unconventional geothermal exploration. This study aims to predict the thermal regime at depth within high-porosity, high-permeability Mesozoic sandstone reservoirs using basin modeling techniques. Basin modeling integrates well log data, formation thickness and lithology to calculate present-day heat flow and subsurface temperatures at locations with existing wells and to predict thermal and flow properties for potential development sites. Approximately nine hundred meters of Triassic-Jurassic strata were measured from the Shnabkaib Member of the Moenkopi Formation through the Lower Navajo Sandstone near Cedar City, Utah, to characterize lithologic character and to sample prospective reservoirs for porosity and permeability analysis. These data, combined with subsurface petrophysical logs and subsurface formation tops, were used to model three existing wells in the basin and to build a predictive model of a generic future development site near Newcastle, Utah. Resulting models indicate elevated surface heat flow near Table Butte in the basin’s center, ranging from 73.9 to 76.7 mW/m², with present-day subsurface temperatures of 130°C at the top of the Navajo Sandstone and 180°C at the base of the Moenkopi Formation. Forward modeling for the New Castle site predicts subsurface temperatures of 150°C and 220°C at equivalent depths, assuming higher heat flows of 86.0 to 86.3 mW/m² in the southern portion of the basin. These temperatures, combined with favorable reservoir properties, highlight the Escalante Basin’s potential for sedimentary geothermal development. We propose that combining reservoir characterization of outcrop analogs with subsurface thermal forecasting using basin modeling techniques offers predictive power for sedimentary geothermal systems and can be applied across the Basin and Range Province.