Fault Gouge Permeability Characterization and Implications for Fluid Migration During Fault Reactivation

Summary Fault zone permeability remains a challenging parameter to address both in outcrop and subsurface. Limited experimental data providing permeability measurements on natural fault rock samples from sealing parts of the fault are available. More data is needed to improve our understanding of fluid migration in faults and dynamic changes related to subsurface injection and the risk of fault reactivation and alteration of the seal capacity. In this work we measure permeability for a natural fault gouge sample from Little Grand Wash Fault zone in Utah using a novel direct shear device. The low permeability measured is in line with a sealing fault core and supports field observations of the damage zone as the main pathway for CO2 migration. The shear loading phase of the experiment suggest a reduction in permeability during shearing and provides key data for improving our understanding of fault reactivation and effects on fluid migration.