Well-based Monitoring Schemes for the South West Hub Project, Western Australia

The South West Hub CCS project (SW Hub) in Western Australia is proceeding to reduce uncertainties related to injectivity, capacity and containment through a well drilling, coring and logging program. This study provides reviews of well designs for in situ tests and well-based monitoring methods at CO₂ storage sites. Wells are expensive and complex engineering undertakings, and their design including size, geometry and materials, greatly impacts on the type of data that can be collected and techniques for monitoring that can be performed at a site. There is no 'one size-fits-all' monitoring well, but there is a tool-box or ensemble of solutions that can achieve a broad range of relevant monitoring objectives given constraints of site characteristics and budgetary limitations. For the SW Hub, a multi-well, multi-use and multi-completion monitoring scheme is proposed that combines the benefit of four different types of monitoring wells in addition to equipping the injector: 1) a well completed in the reservoir for conformance monitoring with additional completion above the storage complex, 2) a well completed above the confining layer for ensuring containment, 3) a well completed in the reservoir in the vicinity of an identified fault for monitoring potential across-fault migration and fault re-activation risks and 4) a well for fault leakage surveillance above the storage complex.