Abstract
A numerical model was developed to predict permeability change due to the interaction between fractured granite rock and NaCl solution. The NaCl solution was employed to replicate the composition of seawater, where Na and Cl are the major elemental components. During the flow-through experiment conducted at a temperature of 20°C (E-28), secondary minerals were precipitated on the fracture surfaces. As a result, there was a significant decrease in fracture permeability. This significant decrease in permeability cannot be replicated by our proposed model because only one secondary mineral was formed during the simulation. In this simulation, three minerals, such as calcite, dawsonite, and halite, are expected to precipitate. Although additional element concentration has been provided by pressure dissolution and free-face dissolution, the oversaturated condition of the calcite and halite mineral has not yet been reached. However, the oversaturated condition of calcite and/or halite might be reached at specific area, for which the underlying mechanism is still unknown.