Dynamic Evolution Mechanism of Hydraulic Conductivity in Heterogeneous Salt Lake Brine Aquifers during Artificial Solution Mining

Artificial solution mining technology, which converts evaporite minerals in brine aquifers into brine, is crucial for the sustainable development of salt lake resources. However, the dynamic evolution of aquifer hydraulic conductivity induced by mineral dissolution during water injection remains insufficiently understood, hindering accurate process prediction. In this study, a Python-based modeling tool, MF6PQC, coupling MODFLOW6 and PhreeqcRM, was developed to systematically investigate the effects of reactive transport on the hydraulic conductivity of brine aquifers and the overall solution mining process. Simulation results show that aquifer heterogeneity governs the spatiotemporal evolution of hydraulic conductivity. During the early stage of dissolution mining, hydrogeochemical reactions preferentially occur in high permeability zones. The dissolution of highly reactive minerals such as carnallite significantly enhances porosity and hydraulic conductivity, ultimately forming preferential flow paths driven by positive advection-dispersion feedback. Relatively homogeneous aquifers or those with extensive, well-connected high-permeability zones facilitate uniform lixiviant distribution and achieve higher solid-to-liquid conversion efficiency. In contrast, strongly preferential or poorly connected formations interrupted by low permeability barriers limit mineral contact and dissolution, thereby reducing overall solution mining efficiency. This study deepens the understanding of hydraulic conductivity evolution in brine aquifers during water injection and provides a theoretical basis for optimizing salt lake brine resource exploitation.