Numerical analysis of spatial - Temporal changes of argillite alteration zoning based on dynamic function of solid - Fluid interface

Hydrothermal alteration in geothermal system causes altered mineral zoning structure and is reflected by fluid chemistry. In situ, metastable clay, and zeolite are difficult, however to numerically simulate in accord with their actual distributions. The argillite alteration in drillhole IT-2 in the eastern part of Sengan geothermal area is analyzed using numerical models based on a dynamic function describing the solid - liquid interface. The model is sensitive to the fluid velocity and temperature conditions that directly reflect borehole fluid chemistry. The numerical analysis can simulate the precipitation and cation exchange of montmorillonite, and the transition from Na-montmorillonite to illite via mixing layers. Additionally, the difference between analytical result and field samples presumed the decline of geothermal activity in this region.