Quantification of leakage into the atmosphere from geologically stored CO2 is achievable by means of atmospheric monitoring techniques if the position of the leak can be located and the perturbation above the background concentration is sufficiently large for discrimination. Geoscience Australia and the CO2CRC have recently constructed a site in northern Canberra for the controlled release of greenhouse gases. This facility enables the simulation of leak events and provides an opportunity to investigate techniques for the detection and quantification of emissions of CO2 (and other greenhouse gases) into the atmosphere under controlled conditions. The facility is modelled on the ZERT controlled release facility in Montana. The first phase of the installation is complete and has supported an above ground, point source, release experiment (e.g. simulating leakage from a compromised well). Phase 2 involves the installation of a shallow underground horizontal well for line source CO2 release experiments and this will be installed during the first half of 2011. A release experiment was conducted at the site to explore the application of a technique, termed atmospheric tomography, to simultaneously determine the location and emission rate of a leak when both are unknown. The technique was applied to the release of two gas species, N2O and CO2, with continuous sampling of atmospheric trace gas concentrations from 8 locations 20m distant from a central release point and measurement of atmospheric turbulence and dispersive conditions. The release rate was 1.10 ± 0.02 g min-1 for N2O and 58.5 ± 0.4 g min-1 for CO2 (equivalent to 30.7 ± 0.2 tonnes CO2 yr-1). Localisation using both release species occurred within 0.5 m (2% error) of the known location. Determination of emission rate was possible to within 7% for CO2 and 5% for N2O.

The CO2CRC Otway Project is Australia's first demonstration of geological storage of CO2 within deep underground reservoirs. The project has undergone many phases of implementation and the latest work program, Phase 2C, is aimed at injecting between 10,000 and 30,000 tonnes of CO2 into the saline Paraatte Formation located around 1,400m below surface. One of the key measures of success for Phase 2C is successful seismic detection of the injected gas stream. The geophysics team from Curtin University of Technology have previously conducted three 3D surface seismic surveys, and numerous smaller experiments, at the Otway CO2 re-injection site. These tests were completed during Phase 1 of the Otway Project whereby an (80-20%) CO2-CH4 gas mixture was re-injected into the depleted Warre-C gas reservoir. The feasibility of seismic monitoring of the CO2-CH4 gas mixture injected into the Paraatte Formation is expected to be improved over the Warre-C reservoir due to the increased fluid property contrast between brine and the CO2-CH4 mixture and the shallower depth of the reservoir. A comprehensive desktop feasibility study has been completed by the Curtin/CSIRO geophysics team to assess the probability of successful seismic detection and the preliminary results are encouraging. A Seismic Assurance Review workshop was completed incorporating seismic expertise from both academia and industry to assess the risk of unsuccessful seismic detection. The workshop was held on the 3rd and 4th of November, 2011, at Curtin University of Technology.

In mid 2011, the Australian Government announced funding of a new four year National CO2 Infrastructure Plan (NCIP) to accelerate the identification and development of sites suitable for the long term storage of CO2 in Australia that are within reasonable distances of major energy and industrial CO2 emission sources. The NCIP program promotes pre-competitive storage exploration and provides a basis for the development of transport and storage infrastructure. The Plan follows on from recommendations of the Carbon Storage Taskforce and the National CCS Council (formerly, the National Low Emissions Coal Council). It builds on the work funded under the National Low Emissions Coal Initiative and the need for adequate storage to be identified as a national priority. Geoscience Australia is providing strategic advice in delivering the plan and will lead in the acquisition of pre-competitive data and geological studies to assess storage potential. Four offshore sedimentary basins (Bonaparte, Browse, Perth and Gippsland basins) and several onshore basins have been identified for pre-competitive data acquisition and study.

In the 2011/12 Budget, the Australian Government announced funding of a four year National CO2 Infrastructure Plan (NCIP) to accelerate the identification and development of suitable long term CO2 storage sites, within reasonable distances of major energy and industrial emission sources. The NCIP funding follows on from funding announced earlier in 2011 from the Carbon Storage Taskforce through the National Carbon Mapping and Infrastructure Plan and previous funding recommended by the former National Low Emissions Coal Council. Four offshore sedimentary basins and several onshore basins have been identified for study and pre-competitive data acquisition.

Geoscience Australia and the CO2CRC have constructed a greenhouse gas controlled release facility at an experimental agricultural station maintained by CSIRO Plant Industry at Ginninderra, Canberra. The facility is designed to simulate surface emissions of CO2 (and other greenhouse gases) from the soil into the atmosphere. CO2 is injected into the soil is via a 120m long slotted HDPE pipe installed horizontally 2m underground. This is fitted with a straddle packer system to partition the well into six CO2 injection chambers with each chamber connected to its own CO2 injection line. CO2 was injected into 5 of the chambers during the first sub-surface release experiment (March - May 2012) and the total daily injection rate was 100 kg/d. A krypton tracer was injected into one of the 5 chambers at a rate of 10 mL/min. Monitoring methods trialled at the site include eddy covariance, atmospheric tomography using a wireless networked array of solar powered CO2 stations, soil flux, soil gas, frequency-domain electromagnetics (FDEM), soil community DNA analysis, and krypton tracer studies (soil gas and air). A summary of the findings will be presented. Paper presented at the 2012 CO2CRC Research Symposium, Sunshine Beach, 27-29 November 2012.

In mid 2011 the Australian Government announced funding of a new four year National CO2 Infrastructure Plan (NCIP) to accelerate the identification and development of sites suitable for the long term storage of CO2 in Australia that are within reasonable distances of major energy and industrial CO2 emission sources. The NCIP program promotes pre-competitive storage exploration and provides a basis for the development of transport and storage infrastructure. The Plan follows on from recommendations from the Carbon Storage Taskforce and the National CCS Council (formerly, the National Low Emissions Coal Council). It builds on the work funded under the National Low Emissions Coal Initiative and the need for adequate storage to be identified as a national priority. Geoscience Australia is providing strategic advice in delivering the plan and will lead in the acquisition of pre-competitive data. Four offshore sedimentary basins (Bonaparte, Browse, Perth and Gippsland basins) and several onshore basins have been identified for pre-competitive data acquisition and study. The offshore Petrel Sub-basin is located in Bonaparte Basin, in NW Australia, has been identified as a potential carbon storage hub for CO2 produced as a by-product from future LNG processing associated with the development of major gas accumulations on the NW Shelf. The aim of the project is to determine if the sub-basin is suitable for long-term storage, and has the potential capacity to be a major storage site. The project began in June 2011 and will be completed by July 2013. As part of the project, new 2D seismic data will be acquired in an area of poor existing seismic coverage along the boundary of the two Greenhouse Gas Assessment Areas, which were released in 2009.

The critical success factors which control hydrocarbon prospectivity in the Otway Basin have been investigated using petroleum systems approaches. Greater than 99% of the hydrocarbon inventory within the Victorian Otway Basin has been sourced from Austral 2 (Albian-Aptian) source rocks and these accumulations are typically located either within, or within approximately 3,000 m of source rock kitchens which are at peak thermal maturity at present day. Importantly, the zones of greatest prospectivity are located where these source rocks have been actively generating and expelling hydrocarbons throughout the Late Tertiary, primarily as a result of sediment loading associated with progradation of the Heytesbury shelfal carbonates. This peak generation window occurs at an average depth of approximately 2,500-3,500 m 'sub-mud' across much of the basin, which has allowed prospective hydrocarbon fairways to be mapped out, thereby highlighting areas of greatest prospectivity. It is believed that the spatial proximity of the actively generating source rocks to the accumulations is due to several factors, which includes overall poor fault seal in the basin (success cases occur where charge rate exceeds leakage rate) and relatively complex and tortuous migration fairways (which means that large volumes of hydrocarbons are only focussed and migrate for relatively short distances). etc

High-CO2 gas fields serve as important analogues for understanding various processes related to CO2 injection and storage. The chemical signatures, both within the fluids and the solid phases, are especially useful for elucidating preferred gas migration pathways and also for assessing the relative importance of mineral dissolution and/or solution trapping efficiency. In this paper, we present a high resolution study focused on the Gorgon gas field and associated Rankin trend gases on Australia's Northwest Shelf of Australia. The gas data we present here display correlate-able trends for mole %-CO2 and %C CO2 both areally and vertically. Generally, CO2 % decreases and becomes depleted in %C (lighter) upsection and towards the north; a trend which also holds true for the greater Rankin trend gases in general. The strong spatial variation of CO2 content and %C and the interrelationship between the two suggests that processes were active to alter the two in tandem. We propose that these variations were driven by the precipitation of a carbonate phase, namely siderite, which is observed as a common late stage mineral. This conclusion is based on Rayleigh distillation modeling together with bulk rock isotopic analyses of core, which confirms that CO2 in gases are genetically related to the late stage carbonate cements. The results from this study have important implications for carbon storage operations and suggest that significant CO2 may be reacted out a gas plume over short migration distances.

Atmospheric monitoring of CO2 geological storage has developed from a concept to reality over less than a decade. Measurements of atmospheric composition and surface to air fluxes are now being made at onshore test sites, pilot projects, operational projects and likely future storage regions around the world. The motivation for atmospheric monitoring is usually to detect potential leakage from CO2 storage activities that might affect health and safety or to test the efficacy of carbon capture and storage (CCS) as a climate mitigation option. We have focused on the mitigation requirement, which involves determining whether potential leakage is below a maximum acceptable rate. Climatic considerations suggest that the maximum leakage rate of stored CO2 should be very small, of the order of 0.01% of that stored per year, globally averaged. Monitoring operational CO2 storage sites to confirm that potential leakage to the atmosphere is below this rate and to locate and quantify the any leakage flux can be a challenge, mainly because of the large and variable CO2 concentrations and fluxes in ecosystems and urban environments. We have developed and assessed atmospheric techniques during field experiments, during 4 years of monitoring the CO2CRC Otway Project, and by using model simulations. From this experience we are able to make recommendations about suitable technologies and strategies to optimise the capability of atmospheric monitoring of CCS in different environments. Abstract for paper to be presented at CO2CRC Research Symposium 2010, 1-3 December 2010, Melbourne

Geological storage of CO₂ requires fundamental knowledge and predictive capabilities on the transport and reactions of injected CO₂ and associated gases to assess the short and long term consequences. CO₂ can be stored in the subsurface through various mechanisms including structural trapping, solubility trapping and by precipitation of carbonate minerals. While mineral strapping is considered to be the safest storage mechanism as it permanently immobilizes the CO₂, the reaction rates and the likely importance for geosequestration is poorly understood. This project has five objectives, which aim to make CO₂ storage more predictable and safer. A range of approaches will be used including desk top studies, laboratory and field experiments and geochemical modelling.