South West Hub Project, Western Australia: appraising ‘migration-assisted' containment for carbon storage in sandstone strata

The South West Hub project (SW Hub) managed by the Department of Mines and Petroleum (DMP) Carbon Strategy Branch, is continuing to build confidence in storage associated with migration assisted trapping (MAT) in unconfined saline aquifers. The area of interest is in the Harvey and Waroona Shires near large CO2 emission sources in the industrial centres of Kwinana and Collie. The injection target is the Lower Lesueur sandstone, a 1500 m thick reservoir with varying permeability layers that should support residual and solubility trapping. The storage complex has no regional shale layer and depends on MAT for primary containment, with the 600 m thick Upper Lesueur with its numerous paleosol baffles as the lower confining layer and the basal shale part of the Eneabba Formation as the upper confining layer. Detailed models have been built based on new 2D/3D seismic surveys and core/log data from the drilling of four wells over a five year period. The results, which include extensive sensitivity analysis, indicate that commercial quantities of CO2 may be injected safely with the plume remaining within the injection reservoir. Uncertainties do remain and the next stage of the program is aimed at reducing these. Significant technical work has also been done through research projects executed by the National Geosequestration Laboratory (NGL) and funded by the Australian National Low Emissions Coal research and development program (ANLEC R&D). This paper will summarise the geological setting, the technical workflow/activities and assurance processes together with the significant community and stakeholder management efforts undertaken.