Regional studies
Review of opportunities for CCS in Victoria
One year after completing the Latrobe Valley CO2 Storage Assessment (LVCSA) the CO2CRC published a Review of Geological Storage Opportunities for Carbon Capture and by Catherine Gibson-Poole et al. This reports on the results of a study that was conducted by the commercial arm of CO2CRC on behalf of the State of Victoria, Department of Primary Industries.
The Latrobe Valley brown coal resources are crucially important to the future development of the State of Victoria, and the Victorian State Government is committed to developing these resources in an environmentally responsible manner. Carbon capture and storage (CCS) is one possible method for reducing large volumes of greenhouse gas emissions. CO2 can be stored geologically by a variety of different options, of which deep saline formations, depleted oil and gas fields, and coal beds are the three main ones. A regional characterisation process is used to establish the potential of an area for CO2 geological storage before an actual site location is selected. The report provides a technical overview — effectively a “state of knowledge” report — that documents the basin-scale suitability of Victoria for CCS, and identifies and prioritises potential Victorian CO2 geological storage opportunities, in both onshore and offshore geological settings.
The sedimentary basins of Victoria, including the Otway, Gippsland and Murray Basins, plus the underlying Late Palaeozoic infrabasins and the smaller Tertiary basins, have been screened and ranked as to their overall suitability for CO2 geological storage, based on geological, geographical and industrial characteristics. These include factors such as tectonic stability, basin size and depth, reservoir or coal quality, intensity of faulting, existing resources and industry maturity. The criteria relate to either the containment security, the volume of storage capacity achievable, or consider the economic or technological
Map of Victoria, southeast Australia, showing the location of the sedimentary basins assessed for this study
A qualitative comparison between the various basins indicates that the offshore Gippsland Basin has the
best overall potential for CO2 geological storage. This basin is relatively stable tectonically, has a thick and
extensive sedimentary fill with numerous reservoir and seal horizons (including a proven regional seal), has
moderate to limited faulting (generally confined to the deeper stratigraphic intervals), has mature
hydrocarbon fields (many of which are reaching depletion) and has an established infrastructure
framework. The offshore Gippsland Basin was followed in the rankings by the onshore Otway Basin, the
offshore Otway Basin and the onshore Gippsland Basin. The Tertiary and Late Palaeozoic basins show
little potential for CO2 storage opportunities (with the Ovens Graben showing the least potential of all the
areas assessed) because they are variously either too small, too shallow or without suitable geological
horizons. The onshore Otway Basin provides the best potential for CO2 storage within an onshore setting
because its depth range is optimal for CO2 storage capacity and its onshore location means that the
technological and economic feasibility is favourable. A potential downside to the onshore Otway Basin,
however, is its extensive faulting, which may limit the storage capacity to smaller volumes and may pose a
containment risk (although many of the faults are in fact sealing faults as they provide the traps for the
petroleum accumulations and may therefore also provide effective traps for CO2). The onshore Gippsland
Basin has the best potential for opportunities to store CO2 within coal beds in association with enhanced
coal bed methane recovery, as it has coals up to bituminous in rank that are located in the optimum depth
range of 300–800 m.
The basin-scale suitability assessments and the comparative rankings are all based on publicly available reports and data that were available at the time of this study (late 2006). The study is intended to provide a broad overview of the possible geological storage opportunities for CCS that may exist within the State of Victoria but is not an exhaustive study. As new data and information are obtained in the basins from continued exploration or subsequent release from confidential sources, the perceived potential of these basins may change and other opportunities not considered previously might become a possibility.
Overall, the geological settings of the State of Victoria and its adjacent waters show considerable potential for CCS opportunities. The adoption of CCS technologies by Victoria will be an important part of the solution to the problem of reducing large volumes of greenhouse gas emissions to the atmosphere.
