As part of the Australian Government National CO2 Infrastructure Plan (NCIP), Geoscience Australia is undertaking CO2 storage assessment of the Vlaming Sub-basin located offshore Western Australia in the southern Perth Basin. The Vlaming Sub-basin is a Mesozoic depocentre containing up to 14 km of sediments. Close proximity of the basin to industrial polluters in the Perth area dictates the need to find CO2 storage solutions in this basin. The main reservoir unit identified as suitable for storage of CO2 is the Early Cretaceous Gage Sandstone deposited in paleo-topographic lows of the Valanginian breakup unconformity. The reservoir unit is laterally extensive (over 1,500 km2) and over most of the area reasonably thick (100 - 300 m). It lies at depths between 1400 and 2000 m below the seafloor, which is suitable for injection of the supercritical CO2 and makes it an attractive target for the long-term storage. The reservoir unit is overlain by a thick deltaic to shallow marine succession of the South Perth Shale, which represents a regional seal in the area. Carbon Storage taskforce estimated that up 1 GT of CO2 can be stored in the Gage Sandstone. The first assessment of the Vlaming Sub-basin undertaken by CO2CRC focused on evaluation of the reservoir unit and overall storage capacity. The current study is based on interpretation and integration of the seismic, well and marine datasets, both existing and acquired since the previous assessment. It includes detailed analysis of reservoir and seal properties and a comprehensive evaluation of the seal integrity risks to allow a more accurate and realistic modeling for CO2 storage.

Introduction This National Carbon Infrastructure Plan study assesses the suitability of the Vlaming Sub-basin for CO2 storage. The Vlaming Sub-basin is a Mesozoic depocentre within the offshore southern Perth Basin, Western Australia (Figure 1). It is around 23,000 km2 and contains up to 14 km of sediments. The Early Cretaceous Gage Sandstone was deposited in paleo-topographic lows of the Valanginian breakup unconformity and is overlain by the South Perth Shale regional seal. Together, these formations are the most prospective reservoir/seal pair for CO2 storage. The Gage Sandstone reservoir has porosities of 23-30% and permeabilities of 200-1800 mD. It lies mostly from 1000 - 3000 m below the seafloor, which is suitable for injection of supercritical CO2 and makes it an attractive target as a long-term storage reservoir. Methods & datasets To characterise the Gage reservoir, a detailed sequence stratigraphic analysis was conducted integrating 2D seismic interpretation, well log analysis and new biostratigraphic data (MacPhail, 2012). Paleogeographic reconstructions of components of the Gage Lowstand Systems Tract (LST) are based on seismic facies mapping, and well log and seismic interpretations. Results The Gage reservoir is a low stand systems tract that largely coincides with the Gage Sandstone and is defined by the presence of the lower G. mutabilis dinoflagellate zone. A palynological review of 6 wells led to a significant revision, at the local scale, of the Valanginian Unconformity and the extent of the G. mutabilis dinoflagellate zones (MacPhail, 2012). G. mutabilis dinoflagellates were originally deposited in lagoonal (or similar) environments and were subsequently redeposited in a restricted marine environment via mass transport flows. Mapping of the shelf break indicates that the Gage LST was deposited in water depths of >400 m. Intersected in 8 wells, the Gage LST forms part of a sand-rich submarine fan system (Figure 2) that includes channelized turbidites, low stand fan deposits, debris flows (Table 1). This interpretation is broadly consistent with Spring & Newell (1993) and Causebrook (2006). The Gage LST is thickest (up to 360 m) at the mouth of large canyons adjacent to the Badaminna Fault Zone (BFZ) and on the undulating basin plain west of Warnbro 1 (Figure 1). Paleogeographic maps depict the evolution of the submarine fan system (Figure 3). Sediment transport directions feeding the Gage LST are complex. Unit A is sourced from the northern canyon (Figure 3a). Subsequently, Unit B (Figure 3b) derived sediment from multiple directions including incised canyons adjacent to BFZ and E-W oriented canyons eroding into the Badaminna high. These coalesce on an undulating basin plain west of Warnbro 1. Minor additional input for the uppermost Unit C (Figure 3c) is derived from sources near Challenger 1. Summary 1: The Gage LST is an Early Cretaceous submarine fan system that began deposition during the G. mutabilis dinoflagellate zone. It ranges from confined canyon fill to outer fan deposits on an undulating basin plain. 2: The 3 units within the Gage LST show multidirectional sediment sources. The dominant supply is via large canyons running north-south adjacent to the Badaminna Fault Zone. 3: Seismic facies interpretations and palaeogeographic mapping show that the best quality reservoirs for potential CO2 storage are located in the outer fan (Unit C sub-unit 3) and the mounded canyon fill (Unit A). These are more likely to be laterally connected. 4: The defined units and palaeogeographic maps will be used in a regional reservoir model to estimate the storage capacity of the Gage LST reservoir.

In 2011 as part of the National CO2 Infrastructure Plan (NCIP), Geoscience Australia started a three year project to provide new pre-competitive data and a more detailed assessment of the Vlaming Sub-basin prospectivity for the storage of CO2. Initial assessment by Causebrook 2006 of this basin identified Gage Sandstone and South Perth Shale (SPS) formations as the main reservoir/seal pair suitable for long-term storage of CO2. SPS is a thick (1900 m) deltaic succession with highly variable lithologies. It was estimated that the SPS is capable of holding a column of CO2 of up to 663m based on 6 MICP tests (Causebrook, 2006). The current study found that sealing capacity of the SPS varies considerably across the basin depending on what part of the SPS Supersequence is present at that location. Applying a sequence-stratigraphic approach, the distribution of mudstone facies within the SPS Supersequence, was mapped across the basin. This facies is the effective sub-regional seal of the SPS. Analysis of the spatial distribution and thickness of the effective seal is used for characterisation of the containment potential in the Vlaming Sub-basin CO2 storage assessment.

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.

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.

In May 2013, Geoscience Australia (GA) and the Australian Institute of Marine Science (AIMS) undertook a collaborative seabed mapping survey (GA0340/ SOL5754) on the Leveque Shelf, a distinct geological province within the Browse Basin, offshore Western Australia. The purpose of the survey was to acquire geophysical and biophysical data on seabed environments over a previously identified potential CO2 injection site to better understand the overlying seabed habitats and to assess potential for fluid migration to the seabed. Mapping and sampling was undertaken across six areas using multibeam and single beam echosounders, sub-bottom profilers, sidescan sonar, underwater towed-video, gas sensors, water column profiler, grab samplers, and vibrocorer. Over 1070 km2 of seabed and water column was mapped using the multibeam and single beam echosounder, in water depths ranging between 40 and 120 m. The sub-surface was investigated using the multichannel and the parametric sub-bottom profilers along lines totalling 730 km and 1547 km in length respectively. Specific seabed features were investigated over 44 line km using the sidescan sonar and physically and sampled at 58 stations. Integration of this newly acquired data with existing seismic data will provide new insights into the geology of the Leveque Shelf. This work will contribute to the Australian Government's National CO2 Infrastructure Plan (NCIP) by providing key seabed environmental and geological data to better inform the assessment of the CO2 storage potential in this area of the Browse Basin. This dataset contains identifications of Polychaetes collected from 64 Smith-McIntyre grabs deployed during GA0340/SOL5754.

This report provides an analysis and evaluation of fluid seepage and habitats in two targeted areas of the Petrel Sub-basin, Bonaparte Basin, northern Australia, and provides scientific information on the seabed and shallow sub-surface geology as part of a study on the potential of this area for CO2 sequestration. The Petrel Sub-basin, located beneath the modern Joseph Bonaparte Gulf, has been assessed by Geoscience Australia as part of the Australian Government funded National Low Emissions Coal Initiative (NLECI) to accelerate the development and deployment of low emissions coal technologies including geological sequestration of CO2. This study is the first undertaken by Geoscience Australia that integrates seafloor and shallow sub-surface geology data to provide information on the potential to sequester CO2 in sub-surface geological reservoirs and their suitability for purpose. In particular, this work involved the integration of data from seabed habitat characterisation studies and sub-surface geological studies to determine if evidence for fluid seepage from depth to the seabed exists at the two study sites within the Petrel Sub-basin. No evidence for hydrocarbons from depth were found. However, fluid seepage at the seabed has been and potentially is occurring; this result stemming from observations on seabe geomorphology, sedimentology, chemistry, and acoustic sub-bottom profiles.

Geoscience Australia undertook a marine survey of the Leveque Shelf (survey number SOL5754/GA0340), a sub-basin of the Browse Basin, in May 2013. This survey provides seabed and shallow geological information to support an assessment of the CO2 storage potential of the Browse sedimentary basin. The basin, located on the Northwest Shelf, Western Australia, was previously identified by the Carbon Storage Taskforce (2009) as potentially suitable for CO2 storage. The survey was undertaken under the Australian Government's National CO2 Infrastructure Plan (NCIP) to help identify sites suitable for the long term storage of CO2 within reasonable distances of major sources of CO2 emissions. The principal aim of the Leveque Shelf marine survey was to look for evidence of any past or current gas or fluid seepage at the seabed, and to determine whether these features are related to structures (e.g. faults) in the Leveque Shelf area that may extend to the seabed. The survey also mapped seabed habitats and biota to provide information on communities and biophysical features that may be associated with seepage. This research, combined with deeper geological studies undertaken concurrently, addresses key questions on the potential for containment of CO2 in the basin's proposed CO2 storage unit, i.e. the basal sedimentary section (Late Jurassic and Early Cretaceous), and the regional integrity of the Jamieson Formation (the seal unit overlying the main reservoir). This dataset comprises sparker sub bottom profiles processed as shallow, high resolution, multichannel seismic reflection data (SEG-Y format), navigation files (P190) and stacking velocities.

Phase two of the China Australia Geological Storage of CO2 (CAGS2) project aimed to build on the success of the previous CAGS project and promote capacity building, training opportunities and share expertise on the geological storage of CO2. The project was led by Geoscience Australia (GA) and China's Ministry of Science and Technology (MOST) through the Administrative Centre for China's Agenda 21 (ACCA21). CAGS2 has successfully completed all planned activities including three workshops, two carbon capture and storage (CCS) training schools, five research projects focusing on different aspects of the geological storage of CO2, and ten researcher exchanges to China and Australia. The project received favourable feedback from project partners and participants in CAGS activities and there is a strong desire from the Chinese government and Chinese researchers to continue the collaboration. The project can be considered a highly successful demonstration of bi-lateral cooperation between the Australian and Chinese governments. Through the technical workshops, training schools, exchange programs, and research projects, CAGS2 has facilitated and supported on-going collaboration between many research institutions and industry in Australia and China. More than 150 experts, young researchers and college students, from over 30 organisations, participated in CAGS2. The opportunity to interact with Australian and international experts at CAGS hosted workshops and schools was appreciated by the participants, many of whom do not get the opportunity to attend international conferences. Feedback from a CAGS impact survey found that the workshops and schools inspired many researchers and students to pursue geological storage research. The scientific exchanges proved effective and often fostered further engagement between Chinese and Australian researchers and their host organisations. The research projects often acted as a catalyst for attracting additional CCS funding (at least A$700,000), including two projects funded under the China Clean Development Mechanism Fund. CAGS sponsored research led to reports, international conference presentations, and Chinese and international journal papers. CAGS has established a network of key CCS/CCUS (carbon capture, utilisation and storage) researchers in China and Australia. This is exemplified by the fact that 4 of the 6 experts that provided input on the 'storage section of the 12th Five-Year plan for Scientific and Technological Development of Carbon Capture, Utilization and Storage, which laid out the technical policy priorities for R&D and demonstration of CCUS technology in China, were CAGS affiliated researchers. The contributions of CAGS to China's capacity building and policy CCUS has been acknowledged by the Chinese Government. CAGS support of young Chinese researchers is particularly noted and well regarded. Letters have been sent to the Secretary of the Department of Industry and Science and to the Deputy CEO of Geoscience Australia, expressing China's gratitude for the Australian Government's support and GA's cooperation in the CAGS project.

As part of Australian Government's National Low Emission Coal Initiative (NLECI) and National CO2 Infrastructure Plan (NCIP), Geoscience Australia (GA) has been assessing offshore sedimentary basins for their CO2 storage potential. These studies, scheduled for completion by 30 June 2015, aim to identify potential sites for the geological storage of CO2 and provide pre-competitive information for the development of CO2 transport and storage infrastructure near major emission sources. The basins targeted for these studies are the Bonaparte Basin (Petrel Sub-basin), Browse Basin, Perth Basin (Vlaming Sub-basin) and Gippsland Basin. GA completed a series of marine surveys over the Petrel and Vlaming sub-basins and the Browse Basin during 2012-2013, that acquired 2D reflection seismic, multibeam bathymetry/backscatter and sub-bottom profiling data, and seabed samples and video footages. The datasets have been analysed to inform the assessment of potential CO2 storage capacity and containment for each study area. Integrated interpretation of the seabed, shallow subsurface and deep basin data has assisted the identification of potential fluid migration features that may indicate seal breach and the presence of migration pathways. Data on seabed environments and ecological habitats will provide a baseline for an assessment of the potential impacts of CO2 injection and storage, and associated infrastructure development.