Characterization of Petrophysical Properties of Different Host-rock Formations for a Deep Geological Repository

摘要

The candidate host rocks for a deep geological repository in Switzerland are analyzed in terms of correlations between petrophysical and geomechanical properties such as clay content, porosity, permeability and effective stress. The analysis leads to a workflow for estimating formation hydraulic properties for the different host rocks and at different depths based on geophysical log data. Consequently, common empirical relationships for permeability are tested for their ability to predict matrix permeability of the candidate formations. The coupled hydro-mechanical observations are additionally verified with micro-structural investigations of the pore space using nanotomography. The derived physical properties are finally compared to analyses of packer tests, evaluating the predictive ability of the proposed approach for the different host rock formations, and conclusively ranking them according to the predictability of the barrier function of the host rock.