The Potential for Geological Sequestration of Co2 in Australia: Preliminary Findings and Implications for New Gas Field Development

Abstract

Many industries and researchers have been examining ways of substantially reducing greenhouse gas emissions. No single method is likely to be a panacea, although some options do show considerable promise. Geological sequestration is one option that utilises mature technology and has the potential to sequester large volumes of CO2. This technology may have particular relevance to some of Australia’s major gas resources that are relatively high in CO2. In Australia, geological sequestration has been the subject of research within the Australian Petroleum Cooperative Research Centre’s GEODISC program. A portfolio of potential geological sequestration sites (sinks) has been identified across all sedimentary basins in Australia, and these have been compared with nearby known or potential CO2 emission sources, including natural gas resources. These sources have been identified by incorporating detailed analysis of the national greenhouse gas emission databases with other publicly available data, a process that resulted in recognition of eight regional emission nodes. An earlier generic economic model for geological sequestration in Australia has been updated to accommodate the changes arising from this process of source to sink matching. Preliminary findings have established the relative attractiveness of potential injection sites through a ranking approach. It includes the ability to accommodate the volumes of sequesterable greenhouse gas emissions predicted for the adjacent region, the costs involved in transport, sequestration and ongoing operations, and a variety of technical geological risks. Some nodes with high volumes of emissions and low sequestration costs clearly appear to be suitable, whilst others with technical and economic issues appear to be problematic. This assessment may require further refinement once findings are completed from the GEODISC site-specific research currently underway.

Investigation of offshore thermal power plant with carbon capture as an alternative to carbon dioxide transport

“…The Australian offshore gas fields are mostly located off the west coast in the Carnarvon, Browse and Bonaparte basins (AER, 2010). The suitability of the Australian offshore sedimentary basins for geological storage of CO 2 has been extensively mapped by the Geodisc project (Bradshaw et al, 2002). As can be seen in Fig.…”

Basin-scale Assessment of the Geological CO2 Sequestration Potential of the Sydney Basin, Australia: Part One

“…Each of the identified potential storage sites can then be compared and ranked using five key risk factors Rigg et al, 2001;Bradshaw et al, 2002;CO2CRC, 2008 With respect to the hydrogeological assessment, the pressure data were allocated within the hydrostratigraphic framework and corresponding hydraulic-head values were mapped for different aquifer units to establish the direction of formation water flow. Vertical pressure profiles can be used to assess the integrity of intervening aquitards between aquifers.…”

“…Possible drawbacks may be the physical size of the structural/stratigraphic trap (i.e. potential storage capacity may be limited) and the timing of availability of depleted fields with respect to the source of CO 2 Bradshaw et al, 2002). In EOR or EGR, the CO 2 is used to incrementally increase the cumulative volume of hydrocarbons extracted by either immiscible or miscible flooding, thus providing an economic benefit while CO 2 is stored.…”

“…They have been identified by many studies as one of the best potential options for CO 2 geological storage because they are widespread and have a large potential volume for storage (e.g. Bachu, 2000;Bradshaw et al, 2002). CO 2 is best injected into saline formations as a dense, supercritical fluid rather than as a gas, as in this compressed supercritical form more than 100 times as much CO 2 can be stored within the pore spaces.…”

“…Technical and economic constraints will reduce this number even further. The majority of stationary CO 2 emitters in NSW lie within the Sydney Basin, which represents the biggest CO 2 emissions node in Australia with the largest concentration of major stationary emitters in Australia (Bradshaw et al, 2002). The largest CO 2 emitters in the Sydney Basin are the major power stations located near Lake Macquarie, in the Hunter Valley and in the western Sydney Basin as well as the Port Kembla Steelworks near Wollongong.…”