Evolution of permeability in siliceous rocks induced by mineral dissolution and precipitation

Yasuhara, Hideaki*; Kinoshita, Naoki*; Kurikami, Hiroshi ; Nakashima, Shinichiro*; Kishida, Kiyoshi*

A conceptual model is presented to follow the evolution of permeability in diatomaceous rocks mediated by pressure solution. Specifically, the main minerals of diatomaceous rocks that are quartz, cristobalite, and amorphous silica, are focused to examine differences of the permeability evolutions among them at effective pressures of 1, 5, 10 MPa, and temperatures of 20 and 90 degrees. The rates and magnitudes of permeability reduction increase with increases of the pressures and temperatures applied. Ultimate permeabilities reduced by the order of 90 % at the completion of dissolution-mediated compaction at 10 MPa and 90 degrees. Precipitation may augment more degradation of flow transport in time.