Replication Data for: \"Laboratory Evaluation of Mechanical Properties of Draupne Shale Relevant for CO2 Seal Integrity\"

The dataset provides experimental data used in the analysis leading up the publication \"Laboratory Evaluation of Mechanical Properties of Draupne Shale Relevant for CO2 Seal Integrity\". Data provided is from triaxial compression tests and one incremental loading oedometer test on the Draupne shale from the Ling depression.
Results are presented from one oedometer and eleven triaxial compression tests on vertical and horizontal samples of the North Sea Draupne shale aimed at deriving me-chanical caprock properties relevant for seal integrity evaluation during CCS operations. Important findings from the laboratory study are: • For the intact vertical samples an apparent cohesion of 7.5 MPa and a friction angle of 18.7° was estimated based on constructed Mohr Coulomb failure envelope. Rela-tively similar values were found for the horizontal samples (cohesion 8.4 MPa and friction 19.4°). In terms of residual strength, the constructed failure envelopes showed a significant reduction in cohesion, whereas the reduction in friction angles was less significant. Both intact and residual strengths are important in operational design of CO2 injection operations to avoid fracture creation or reactivation of pre-existing weakness planes. • Secant undrained Young's modulus measured between 40 and 60 % of peak stress was between 4.2 and 4.7 GPa for vertical samples and 5.7 – 7.1 GPa for horizontal samples. Average secant Poisson's ratio for samples of both principal directions were close to 0.5. • Whereas the measured constrained modulus from oedometer testing showed little or no stress dependency, the consolidation coefficient decreased with increasing effec-tive vertical stress. Hydraulic permeability estimated from constrained modulus and consolidation coefficient therefore also decreased with increasing effective vertical stress. Increasing effective vertical stress from 33 to 75 MPa caused a reduction in hy-draulic permeability of nearly 50 %. • The apparent pre-consolidation stress determined from oedometer incremental loading was 36.5 MPa. Consequently, the tested Draupne shale is considered nor-mally consolidated to lightly overconsolidated. The measured undrained strength from triaxial normalized against the effective vertical consolidation stress correlated quite well with overconsolidation ratio following the SHANSEP normalization pro-cedure developed for clays.