Mechanical Anisotropy Characterization of the Draupne Formation, North Sea

Anisotropy is an important characteristic for the mechanical characterization of shale. Both strength and elastic parameters vary with orientation of material due to the lithological anisotropy in the material. A triaxial test program on varying plug orientation was designed to investigate the mechanical anisotropy in the Draupne Formation. From the triaxial experiments, clear strength anisotropy is observed especially in certain range of orientation. Post-test CT images shows that the strength anisotropy is mainly related to failure in bedding planes. The observed strength anisotropy implies that orientation dependent failure criteria should be considered for realistic geomechanical modelling of seal integrity.