The Lesueur Formation storage complex in South Western Australia: safe, secure long-term storage of CO2

Abstract

Carbon capture, utilisation and storage remain critical components of a decarbonised future. The West Australian Department of Mines, Industry Regulation and Safety with research partners CSIRO, Curtin University and the University of Western Australia, have assessed the suitability of storing carbon dioxide in the deep saline aquifers of the Triassic Lesueur Formation (Southern Perth Basin) through the South West Hub Carbon Storage Project (SW Hub). The SW Hub has now concluded its acquisition of pre-competitive data and research. Extensive evaluation and multiple peer reviews by industry concluded that the site is ready for the next stage of characterisation – drilling and testing to confirm or refine the predictions for a suitable commercial-scale geological storage site, enabling acreage release for commercial exploration and appraisal leading to a storage licence. The data package includes extensive geological and dynamic modelling, providing confidence in the storage complex. Four wells have been drilled and multiple seismic data acquisition surveys (including 115 km2 3D seismic) are supported by four generations of reservoir models of increasing complexity built over the last decade of investigations. The site is unique in that there is no regional shale layer above the reservoir to provide a conventional seal for injected carbon dioxide. Results indicate that secure storage is obtained via vertical trapping across the extensive storage formation thickness; if proven, this mechanism can increase storage options around the world. This paper discusses the significance of the site, the geological setting, technical workflow, monitoring strategy and community and stakeholder management activities undertaken.