GEG Group
CPG
TANGO
ETH Zurich

Fully coupled hydro-mechanical–chemical continuum modeling of fluid percolation through rock salt

2025Journal ArticleInternational Journal of Rock Mechanics and Mining Sciences 186, pp. 105985105985

Abstract

In domal and bedded rock salt geothermal reservoirs, geochemical dissolution of the in-situ rock salt formation can alter fluid transport properties, thus impacting fluid flow. Coupled Hydro-mechanical–chemical (HMC) modeling is a useful tool to evaluate fluid transport through rock salt geothermal systems and to assess their economic potential. Existing continuum-based numerical simulation of fluid transport through rock salt relies on the polyhedral orientation of rock salt crystal boundaries as potential fluid pathways, employing a deformation-dependent permeability model to depict pressure-driven fluid flow through rock salt. However, this numerical approach is exclusively HM-coupled and overlooks the influence of halite dissolution/precipitation on the permeability model. This study extends the deformation-dependent permeability model to account for halite dissolution by adopting a reverse mineral growth approach. Using this extended (HMC-coupled) model, we capture the relevance of geochemical reactions on the response of rock salt formations undergoing pressure-driven fluid percolation. The resulting simulations predict a lower fluid pressure than the HM-coupled scenario, highlighting the impact of halite dissolution on fluid flow through rock salt.