Uncertainty Analysis of Chemically Induced Scale Formation in Low to Medium Enthalpy Geothermal Reservoirs

In this study, we conducted a thorough uncertainty analysis to identify key factors influencing chemically induced scale formation in geothermal systems. Using a CCD with minimum-run resolution V design, we assessed the impact of nine common water components and temperature on total precipitated solid minerals. Each modeling run based on the DOE schedule was implemented using PHREEQC, an open-source software dedicated to aqueous chemistry calculations. Employing this model in conjunction with DOE analysis, an extensive exploration of the impact of chemical formulations and temperature variations was conducted. Our findings suggest that geothermal reservoirs with minimal HCO3 and Si ions and either very low or significantly high Ca ion levels are prone to lower solid precipitation. Temperature has a limited effect within the specified range, but caution is needed regarding SO4 ion presence. Results indicate that below 20 degrees, high SO4 concentration negatively impacts solid precipitation, while at higher temperatures, low SO4 values may also have a negative impact. Our study presents the potential for total precipitated solids based on fluid composition and temperature across different geothermal plants, and a discussion on associated clogging risks.