Hydrothermal Fluid Flow and Mineral Alteration in a Fractured Rock under Multiphase

The geochemical evolution of hydrothermal fractured rock systems occurs through a complex interplay of multi-phase fluid and heat flow, and chemical transport processes. On the basis of previous work we present simulations of reactive hydrothermal flow that include (1) detailed fracture-matrix interaction for fluid, heat and chemical constituents, (2) gas phase participation in multiphase fluid flow and geochemical reactions, (3) heat effects on thermophysical and chemical properties and processes, and (4) the kinetics of fluid-rock chemical interaction. Results indicate that vapor-CO2 discharges through fractures in rhyolitic caprock, cause strong alteration of the earlier formed primary minerals and lead to the formation of secondary minerals, resulting in changes in physical and chemical properties of the system.