Numerical modeling of solid precipitation from multicomponent hydrothermal solutions

Geothermal energy is gaining increasing attention as a promising alternative to fossil fuels. The advantage of geothermal power plants over thermal power plants that operate by burning fossil fuels is considered to be the low level of greenhouse gas emissions, primarily carbon dioxide. Another advantage of geothermal power plants is their stable electricity generation, unaffected by time of day or seasonal fluctuations. This distinguishes the use of geothermal resources for electricity generation from solar or wind energy.

At the same time, implementing geothermal energy projects is fraught with a number of challenges. A common problem with geothermal power plants is the precipitation of solids from hydrothermal solutions. Hydrothermal solutions are aqueous solutions that are chemically rich in various substances. When temperature or pressure changes, when minerals dissolve further, or when pH changes, solid precipitates may fall out of such solutions. These processes can have a negative effect and occur in production and reinjection wells, in surface equipment and heat exchangers, as well as in the porous rocks of the geothermal reservoir. Since all of this affects the ultimate efficiency of geothermal energy projects, it is important to study these geochemical processes, including through numerical modeling.

We discuss a mathematical model that can describe the process of solid precipitation from multicomponent hydrothermal solutions moving under the action of a pressure gradient (in a wellbore or in a porous reservoir rock). We show that the considered mathematical model allows us to draw correct conclusions about the growth of solid deposits in wells of a geothermal field in Kamchatka (Russia), consistent with empirical data.

This work is supported by the Russian Science Foundation under grant 24-77-10022.