Use of rock mechanics laboratory data in geomechanical modelling to increase confidence in CO2 geological storage

One of the many challenges facing carbon capture and storage will be to provide convincing evidence of the geomechanical integrity of any proposed geological storage site. Contrary to storage in depleted hydrocarbon fields, storage in saline aquifer presents many more unknowns in this respect because there will probably be no known previous pressure response history or rock property characterisation. The work presented here was carried out as part of a project investigating the improvement in levels of confidence in all aspects of site selection and characterisation that could be expected with increasing data availability for saline aquifers. Attention here was focused on geomechanical modelling and the rock mechanics data used to populate these models. The models initially used generic geomechanical property data and the potential for shear failure of the intact rock and (fault) reactivation of fractured rock investigated. The models were then updated with laboratory measured rock mechanical properties for actual rock from the proposed storage system locality. The modelled results were changed marginally but did not identify any significant issues of criticality because of the relative geomechanical “benignness” of the storage site.