This session is aimed towards different aspects of permeability, including its laboratory and in situ measurement and its critical upscaling required for modeling geological systems. We welcome keen laboratory and in-situ researchers as well as numerical modelers to discuss the challenges in and relevance of permeability assessment, regardless of the type of host rock or barrier material.

Key Laboratory Topics:
• Challenges in Measuring Low Permeability: Explore the pitfalls of measuring the lowest permeability values and how to overcome them.
• Unverified Method Comparability and Round-Robin Tests: Discuss the variability across measurement techniques and how collaborative round-robin testing can pave the way for greater comparability.
• Standardization Procedures for Site Selection: Debate the feasibility of developing standard procedures for permeability measurements, which are crucial for reliable evaluation and eventual site selection.
In Situ Measurement Topics:
• Distinguishing Flow Processes Across Scales: How to measure, distinguish and map fracture and matrix flow?
• Spatial and Volumetric Extrapolation: Discuss how to extrapolate localized permeability measurements to larger, reservoir or disposal-site scales, ensuring representativeness and reliability in assessments.
Numerical Modeling Topics:
• Upscaling Micro-Scale Processes: Delve into how small-scale measurements can be scaled to accurately represent larger geological systems.
• Fracture Networks to Equivalent Porous Media: Examine methods to modify discrete fracture networks into equivalent porous media to support the development of large-scale, realistic digital twins of geological systems.
• Future developments of barriers and geosphere: How to deal with changes of porosity due to mechanical load or precipitation of secondary phases, how (un)certain is pore-clogging?

The session will also provide room to discuss two-phase flow, relative permeability and the material dependency of environmental controls, which might dynamically change throughout the long-term evolution of a repository.