Investigating Reinjection Strategies to Optimise Lithium Production from the Salton Sea Geothermal Field

Abstract

The Salton Sea Geothermal Field (SSGF) is one of the largest geothermal resources in the world with an estimated resource potential of nearly 3 GW (Kaspereit et al., 2016). It has only been partially exploited due to its high salinity and partial coverage by the Salton Sea. Stakeholders are now focused on better exploiting the field for geothermal energy production and using the lithium-rich geothermal brine as a source of lithium for battery production. This modeling study uses our existing numerical model of the SSGF to investigate different options for optimising the extraction of lithium from the system. Our model of the SSGF has a chloride-NCG-water equation of state with lithium represented as a passive tracer (Araya and OSullivan, 2022, Dobson et al., 2023, OSullivan et al., 2023a). The model uses a dual porosity approach for the production history and future scenarios to provide an accurate representation of reinjection returns and chemical breakthrough by dilute lithium reinjection fluid. Publicly available data has been used to calibrate both the natural state and production history models. Future scenarios were run to investigate the influence of the location of reinjection wells on both pressure support and lithium concentrations in produced geothermal brine. They show that lithium production can be enhanced without adversely affecting energy production by careful targeting of reinjection. The results of the simulations show the importance of careful monitoring, robust modelling and detailed planning in supporting the extraction of lithium from the SSGF.