The Geological Storage Potential Of Supercritical CO2 In The Arckaringa Basin, South Australia
Fry, Clayton L. S.
Geoscience Honours Degree, 2011
University of Adelaide
The Arckaringa Basin is situated in central-northern South Australia, and extends for over 80,000 square kilometres. Very little research has been done in the Arckaringa and, while no significant oil or gas reserves have been discovered, the search for unconventional resources, most notably coal seam gas, has become more intensive in recent years. This study investigates whether or not the Arckaringa Basin has the potential for storage of CO2 in its supercritical state. The storage of CO2 will help to limit the amount of CO2 released in to the atmosphere. Geological storage within the Arckaringa Basin is investigated in this study.
The findings have revealed that the Arckaringa Basin has the potential to store supercritical CO2 at depth in certain formations within the Arckaringa Basin. The depth to supercritical CO2 in the Arckaringa Basin is 752 m, assuming normal hydrostatic and lithostatic conditions. Due to the high geothermal gradient of the Arckaringa Basin, the storage density of CO2 will be reduced noticeably. Storage density is the property by which the supercritical CO2 is denser at lower temperatures, compared to being less dense at warmer temperatures. The warm geothermal gradient can cause complications for further studies in the Arckaringa Basin, however further research will be needed to determine if the Arckaringa Basin is both economically and environmentally feasible as a permanent project. Such research includes; mercury injected capillary pressure (MICP) for reservoir and seal quality analysis, additional dense (closely spaced) seismic surveys would also aid in further studies. Economically, the distance from Port Augusta to the Arckaringa basin, opens the potential to transport CO2 emissions from Port Augusta from industrial sites and power stations via pipeline. The distance to the basin from Port Augusta, is approximately 450 km to the Arckaringa Basin. There is also the possibility of CO2 emissions from mine sites in the Roxby Downs being connected via pipeline as well.
Further investigations should look into the formations that underlie the Arckaringa Basin, such as the Cootanoorina Formation, which is believed to be part of the Officer Basin. This formation is a carbonate rock with excellent secondary vugular porosity and open stylolite fractures, indicating the potential for residual gas trapping of supercritical CO2 at depth.