Laboratory Evaluation of Mechanical Properties of Draupne Shale Relevant for CO2 Seal Integrity

The mechanical integrity of caprocks overlying injection formations is one the key factors for safe storage carbon dioxide in geological formations. Undrained effects caused by CO2 on strength and elastic parameters should be properly considered operational design to avoid fracture creation, fault reactivation unwanted surface uplift. This study presents results from eleven undrained triaxial compression tests oedometer test Draupne shale, which main caprock Smeaheia site North Sea, extract relevant seal integrity. Tests have been performed samples oriented perpendicular parallel with horizontal layering rock sample orientation relative loading direction. Results showed only minor friction cohesion. However, when during shearing was (horizontal samples), measured Young’s modulus roughly 1.4 times higher than vertical samples. generated 30–50% more excess pore pressure similar consolidation stress owing volume compaction With apparent pre-consolidation determined a high-stress test, normalized shear found correlate well overconsolidation ratio following SHANSEP (Stress History Normalized Soil Engineering Properties) procedure.