The Collaborative Research Centre for Greenhouse Gas Technologies (CO2CRC) Program 3.2 Risk Assessment is working toward a risk assessment procedure that integrates risk across the complete CCS system and can be used to meet the needs of a range of stakeholders. Any particular CCS project will hold the interest of multiple stakeholders who will have varied interests in the type of information and in the level of detail they require. It is unlikely that any single risk assessment tool will be able to provide the full range of outputs required to meet the needs of regulators, the general public and project managers; however, in many cases the data and structure behind the outputs will be the same. In using a suite of tools, a well designed procedure will optimize the interaction between the scientists, engineers and other experts contributing to the assessment and will allow for the required information to be presented in a manner appropriate for each stakeholder. Discussions of risk in CCS, even amongst the risk assessment community, often become confused because of the differing emphases on what the risks of interest are. A key question that must be addressed is: 'What questions is the risk analysis trying to answer?' Ultimately, this comes down to the stakeholders, whose interests can be broken into four target questions: - Which part of the capture-transport-storage CCS system? - Which timeline? (project planning, project lifespan, post closure, 1,000 years, etc) - Which risk aspect? (technical, regulatory, economic, public acceptance, or heath safety and environment) - Which risk metric? (Dollars, CO2 lost, dollars/tonne CO2 avoided, etc.) Once the responses to these questions are understood a procedure and suite of tools can be selected that adequately addresses the questions. The key components of the CO2CRC procedure we describe here are: etc

The Early Cretaceous Gage Sandstone and South Perth Shale formations are one of the most prospective reservoir-seal pairs in the Vlaming Sub-basin. Plays include post-breakup pinch-outs with the South Perth Shale forming a top seal. The Gage reservoir has porosities of 23-30% and permeabilities of 200-1800 mD and was deposited in palaeotopographic lows of the Valanginian breakup unconformity. This is overlain by the thick deltaic South Perth (SP) Supersequence. To characterise the reservoir-seal pair, a detailed sequence stratigraphic analysis was conducted by integrating 2D seismic interpretation, well log analysis and new biostratigraphic data. The palaeogeographic reconstructions for the Gage reservoir are based predominantly on the seismic facies mapping, whereas SP Sequence reconstructions are derived from mapping higher-order prograding sequences and establishing changes in sea level and sediment supply. The Gage reservoir forms part of a sand-rich submarine fan system and was deposited in water depths of > 400 m. It ranges from confined canyon fill to fan deposits on a basin plain. Directions of sediment supply are complex, with major sediment contributions from a northern and southern canyon adjacent to the Badaminna Fault Zone. The characteristics of the SP Supersequence differ markedly between the northern and southern parts of the sub-basin due to variations in palaeotopography and sediment supply. Palaeogeographic reconstructions reveal a series of regressions and transgressions leading to infilling of the palaeo-depression. Seven palaeogeographic reconstructions for the SP Supersequence portray a complex early post-rift depositional history in the central Vlaming Sub-basin. The developed approach could be applicable for detailed studies of other sedimentary basins

Abstract for submission to 11th IEA GHG International Conference on Greenhouse Gas Control Technologies. Conference paper to follow pending selection for oral or poster presentation. Abstract covers the GA-ACCA21 China Australia Geological Storage of CO2 (CAGS) Project run through PMD/ED 2009-2012.

Atmospheric tomography is a monitoring technique that uses an array of sampling sites and a Bayesian inversion technique to simultaneously solve for the location and magnitude of a gaseous emission. Application of the technique to date has relied on air samples being pumped over short distances to a high precision FTIR Spectrometer, which is impractical at larger scales. We have deployed a network of cheaper, less precise sensors during three recent large scale controlled CO2 release experiments; one at the CO2CRC Ginninderra site, one at the CO2CRC Otway Site and another at the Australian Grains Free Air CO2 Enrichment (AGFACE) facility in Horsham, Victoria. The purpose of these deployments was to assess whether an array of independently powered, less precise, less accurate sensors could collect data of sufficient quality to enable application of the atmospheric tomography technique. With careful data manipulation a signal suitable for an inversion study can be seen. A signal processing workflow based on results obtained from the atmospheric array deployed at the CO2CRC Otway experiment is presented.

Between 2009 and 2012, Australia and China successfully completed the first phase of a bilateral project that aimed to build capacity in the area of geological storage of carbon dioxide among Chinese researchers, students, policy makers and professionals from academia, government and industry. This paper details the activities and results of the International CCS CAGS project, Phase I.

A major concern for regulators and the public with geologically storage of gas is the potential for the migration of gas (e.g. CO2) via a leaky fault or well into potable groundwater supplies. Given sufficient CO2, an immediate effect on groundwater would be a decrease in pH which could lead to accelerated weathering, an increase in alkalinity and the release of major and minor ions. Laboratory and core studies have demonstrated that on contact with CO2 heavy metals can be released under low pH and high CO2 conditions (particularly Pd, Ni and Cr). There is also a concern that trace organic contaminants could be mobilised due to the high solubility of many organics in supercritical CO2. These scenarios could potentially occur under a high CO2 leakage event but a small leak might be barely perceptible yet could provide an important early warning for a subsequent and more substantial impact. Different approaches are required for the detection and quantification of these low level leaks and are the subject of this paper. A 3 year groundwater survey was recently completed in the Surat Basin, which forms part of the Triassic-Cretaceous, Great Artesian Basin (GAB) aquifer sequence. In addition to a comprehensive water and isotopic analysis of samples from groundwater wells, gases were collected from groundwater samples and analysed for composition, '13CCO2, '13CCH4 and '2HCH4. Methane is prevalent in the major aquifers in the Surat Basin (e.g. Mooga, Gubbermunda and Hutton sandstones) and is invariably associated with a bacterial (methanogenic) carbonate reduction source, evident from its isotopic signature ('13CCH4 ~ -70', '2HCH4 ~ 220'). In addition to methane and low levels of CO2, trace levels of ethane are often detected.

Geoscience Australia has recently completed the Bonaparte CO2 Storage project, an assessment of the CO2 storage potential of the Petrel Sub-basin. In 2009, two greenhouse gas assessment leases were released, PTRL-01 and PTRL-02, under the Offshore Petroleum and Greenhouse Gas Storage Act of 2006. Both are proximal to the developing LNG market in Darwin, as well as a number of hydrocarbon accumulations in the Bonaparte Basin. A key phase of the project was geological modelling to test CO2 injection scenarios. Initial 3D seismic horizon surfaces were generated to create a 'simple' geological model. A 'complex' geological model was built by integrating a structure model, which was depth converted. Subsequently, models were populated with reservoir properties such as Vshale, porosity and permeability. Palaeogeography maps were generated for all key stratigraphic units and were used to populate the model where well control was lacking. Using Permedia', CO2 migration simulations with randomly located injection wells were run on a high resolution model to study the migration pathways, major accumulations and the effects of vertical anisotropy. Smaller areas of interest were then identified to reduce the size of the model and allow fluid flow reservoir simulations study using Permedia' and CMG-GEM'. The later study estimated the practical injectivity, storage volume, reservoir pressure during and after CO2 injection.

Carbon capture and storage is a mitigation strategy that could rapidly reduce CO2 emissions from high emission sources. However, the exploration and assessment of reservoirs for the geological storage of CO2 is a complicated science commonly hampered by large uncertainties. The major hurdles lie in correctly assessing the prospectivity of basin plays, and ultimately of play fairways suitable for CO2 storage. On the North West Shelf of Australia, turbidite deposits are a common depositional system and many are considered prospective for CO2 storage in this emission intensive part of Australia. Using an integrated reservoir modelling approach, this study assessed the storage potential of the Caswell Fan turbidite in the Browse Basin, Western Australia. A detailed seismic interpretation utilising both 2D and 3D seismic and four previously drilled wells, provided the sequence stratigraphic framework for a detailed reservoir evaluation. The Fan was deposited in a basin floor fan setting within a lowstand systems tract, which provided optimal conditions for sequestration due to the sandstone's extended geometry, sorting, and high net-to-gross ratios, all overlain by a regional marine claystone seal. Through 3D static geological modelling it was determined that the Caswell Fan had an estimated storage capacity of approximately 300 million tonnes of CO2. This largely unconfined basin floor fan represents one of several plays along the North West Shelf of Australia, which could provide suitable CO2 storage formations for the carbon capture and storage industry.

A question and answer style brochure on geological storage of carbon dioxide. Questions addressed include: - What is geological storage? - Why do we need to store carbon dioxide? - How can you store anything in solid rock? - Could the carbon dioxide contaminate the fresh water supply? - Could a hydrocarbon seal leak? - Are there any geological storage projects in Australia?

Identification of major hydrocarbon provinces from existing world assessments for hydrocarbon potential can be used to identify those sedimentary basins at a global level that will be highly prospective for CO2 storage. Most sedimentary basins which are minor petroleum provinces and many non-petroliferous sedimentary basins will also be prospective for CO2 storage. Accurate storage potential estimates will require that each basin be assessed individually, but many of the prospective basins may have ranges from high to low prospectivity. The degree to which geological storage of CO2 will be implemented in the future will depend on the geographical and technical relationships between emission sites and storage locations, and the economic drivers that affect the implementation for each source to sink match. CO2 storage potential is a naturally occurring resource, and like any other natural resource there will be a need to provide regional access to the better sites if the full potential of the technology is to be realized. Whilst some regions of the world have a paucity of opportunities in their immediate geographic confines, others are well endowed. Some areas whilst having good storage potential in their local region may be challenged by the enormous volume of CO2 emissions that are locally generated. Hubs which centralize the collection and transport of CO2 in a region could encourage the building of longer and larger pipelines to larger and technically more viable storage sites and so reduce costs due to economies of scale.