Updated Modelling of the Salton Sea Geothermal Field

Abstract

The Salton Sea Geothermal Field (SSGF) is one of the world largest geothermal resource with an estimated resource potential of nearly 3 GW and dissolved minerals such as lithium of high interest. Despite a long history of producing and reinjecting into the deep geothermal system, the brine's complex high salinity and dissolved solid content are challenging in assessing future operations and forecasting the management of the SSGF. New developments on the SSGF are ongoing to exploit the deep geothermal system for geothermal energy production and use the lithium-rich geothermal brine as a source of lithium for battery production. We present an updated numerical model of the SSGF field using a chloride-NCG-water equation of state with lithium as a passive tracer (Araya and O Sullivan, 2022, Dobson et al., 2023, O Sullivan et al., 2023a). Based on our previous modelling approach representing the production history and future scenarios, we have refined the model grid to provide a more accurate match of the reinjection returns and chemical breakthrough by diluted lithium reinjection fluid. Publicly available data was used to calibrate the updated model for both the natural state and production history. A preliminary uncertainty quantification of the updated model has been carried out varying the key unknown parameters (porosities, permeabilities, upflows). The results provide a refined understanding of the SSGF and demonstrate the capability of uncertainty quantification for providing robust ranges of forecasts including rates of lithium extraction. The results highlight the need for robust, integrated geothermal reservoir modelling with uncertainty quantification to support planning the sustainable utilization of geothermal energy and extraction of lithium from the SSGF.