Estimating the permeability of crystalline rocks from geological data in remote northern environments: advantages and limitations

Permeability is a key parameter for geothermal feasibility studies; however, this parameter is difficult to determine in regions where complex field logistics hinder the completion of hydraulic tests during the early stages of projects. This highlights the need to develop simple, yet reliable methods to characterize hydraulic properties from geological assessments other than hydraulic testing. The aim of this work was to develop a comprehensive method for a first-order permeability assessment in the context of geothermal energy development in regions where conventional methods are difficult to deploy. Permeability estimates suggest that methods based on the fracture network connectivity and fracture aperture prediction models outperform traditional cubic law approaches. The resulting permeability estimates are comparable with Porchet test results and global databases of bedrock permeability. Although hydraulic testing is necessary to validate the permeability estimates, the methodology presented here provides an effective preliminary tool that can assist in future geothermal studies in crystalline basement rocks within remote regions.