South West Hub CCS Project in Western Australia – Characterisation of a Greenfield Site.

The South West Hub Project (SWH) is undergoing pre-feasibility assessment through a stage-gated program of data acquisition, managed currently by the Western Australia Department of Mines and Petroleum (WA DMP). Undergoing assessment for potential to store commercial quantities of CO2 is an area of approximately 150 km2 north of the town of Harvey in south west Western Australia. The emissions hub of Collie (∼ 70 km to the SE) is the home to some likely users of the pore space if the site proves up. In contrast to many potential storage projects, the area under investigation had undergone only limited geological evaluation prior to this project's initiation in 2007. Therefore a program of data acquisition has had to be developed and undertaken to populate an essentially greenfield site, to provide sufficient information to make informed decisions prior to proceeding through each stage gate. Activities to date have included: A 2D seismic survey (2011) along local roads, which enabled the placement of a stratigraphic well. The drilling of the Harvey-1 stratigraphic well (2012) to a depth of 2920.5 m TVDSS. Research projects have then been commissioned to utilise these new materials and provide additional site characterisation. A small scale 2D seismic survey (December, 2013) to aid in definition of acquisition parameters for a subsequent 3D seismic survey conducted, taking in 115 km2 of the approximate 150 km2 area (February – March, 2014). Results from these activities so far have not presented the project with any “show-stoppers”. The key intervals of interest, the Yalgorup and Wonnerup members of the Triassic Lesueur Formation show suitable rock properties for purposes of carbon storage. Fault identification and their modeled transmissivity do not indicate extensive compartmentalization in the storage region. Whilst the key to this project is residual trapping (Wonnerup as the primary containment interval and Yalgorup as the secondary containment interval) there is improved evidence to suggest the presence of potential baffles and seals in the area to retain the CO2. As at mid-2014, the plan forward will include: 3D seismic processing, interpretation and the building of a new geological model (underway mid - 2014). Drilling of three shallow wells to better characterise the upper layers (2014 - 2015). Flow testing of one of those three wells to better assess the potential baffles (2015). Drilling of a deeper well(s) to characterise the reservoir properties off the Harvey Ridge Structure (late 2015). Related research activities using the new materials generated from the upcoming well drilling and testing program. The recently acquired 3D seismic survey is already providing valuable information to constrain the main formations distribution and aiding in the location of the likely areas for further data acquisition. Complementary research projects are ongoing to facilitate the valuation of the site with the aim of reducing risk and uncertainty as the project proceeds to the next stage gate. It is hoped that by using a stage-gate approach, the pre-feasibility data acquisition will be focused and provide a lower cost and more rapid approach to assessing sites in future.