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.

This geomechanical analysis of the Browse Basin was undertaken as part of the CO2CRC's Browse Basin Geosequestration Analysis. This study aims to constrain the geomechanical model (in situ stresses), and to evaluate the risk of fault reactivation. The stress regime in the Browse Basin is one of strike-slip faulting i.e. maximum horizontal stress (~ 28.3 MPa/km) > vertical stress (22 MPa/km) > minimum horizontal stress (15.7 MPa/km). Pore pressure is near hydrostatic in all wells except for two, which exhibit elevated pore fluid pressures at depths greater than 3500 m. A maximum horizontal stress orientation of 095' was considered to be most appropriate for the Barcoo sub-basin, which was the area of focus in this study. The risk of fault reactivation was calculated using the FAST (Fault Analysis Seal Technology) technique, which determines fault reactivation risk by estimating the increase in pore pressure required to cause reactivation. Fault reactivation risk was calculated using two fault strength scenarios; cohesionless faults (C = 0; ? = 0.6) and healed faults (C = 5; ? = 0.75). The orientations of faults with high and low reactivation risks is almost identical for healed and cohesionless faults. High angle faults striking N-S are unlikely to reactivate in the current stress regime. High angle faults orientated ENE-WSW and ESE-WNW have the highest fault reactivation risk. Due to the fact that the SH gradient was determined using frictional limits, the most unfavourably oriented cohesionless faults cannot sustain any pore pressure increase without reactivating. By contrast, using a cohesive fault model indicates that those same faults would be able to sustain a pore pressure increase (Delta P) of 9.6 MPa. However, it must be emphasized that the absolute values of Delta P presented in this study are subject to large errors due to uncertainties in the geomechanical model, in particular for the maximum horizontal stress. Therefore, the absolute values of Delta-P presented herein should not be used for planning purposes. Fault reactivation risk was evaluated for 10 faults with known orientations. All faults were interpreted as extending from below the Jurassic target reservoir formation to the surface. The dominant fault in the Barcoo sub-basin is the large fault which extends from Trochus 1 to Sheherazade 1 to Arquebus 1. This deeply penetrating, listric fault initially formed as a normal fault and was subsequently reactivated in thrust mode. Most of the faults in the Barcoo sub-basin trend broadly N-S and are therefore relatively stable with respect to increases in pore pressure. However, there are sections within some individual faults where fault orientation becomes close to optimal. In these sections, small increases in pore pressure (<5 MPa) may be sufficient to cause fault reactivation. If this were to occur, then significant risk of CO2 leakage would exist, as these sections cross-cut the regional seal.

Increasing CO2 emissions resulting from the expansion of coal fired power generation capacity and other industry in Queensland suggests that a long-term high capacity storage solution is needed. Despite some relatively large distances (upwards of 500 km) between sources and sinks, a review of the Galilee Basin suggests that it may have the potential to sequester a significant amount of Queensland's stationary CO2 emissions, however a paucity of data in several significant regions do not allow this potential to be fully assessed at the present time. Sandstones with good porosity and permeability characteristics occur within several formations including the Early Permian Aramac Coal Measures, the Late Permian Colinlea Sandstone and the Triassic Clematis Sandstone. Intraformational and local seals as well as a regional seal, the Triassic Moolayember Formation and the Permian Bandanna Formation, appear sufficient although these have not been tested. Stratigraphic and residual/solution trapping are the most likely CO2 storage mechanisms, as low amplitude structures are a feature of the Galilee Basin. Most of the structures targeted by exploration companies are generally too small to store CO2 in the quantities anticipated to be emitted from potential emission nodes such as the Rockhampton-Gladstone region. Regional reconnaissance indicate small 15-20 km2 structures with a 50-125 m net sandstone section are typical for the Clematis Sandstone Formation in the south eastern area of the Galilee Basin. Covering an area of approximately 247,000 km2 and measuring around 700km north-south and 520 east-west, the Galilee Basin is a significant feature of central Queensland. Three main depocentres the Koburra Trough (east), the Lovelle Depression (west) and the Southern Galilee Basin (south) contain several hundred metres of Late Carboniferous to Middle Triassic sediments (up to 3000m, 730m, and 1400m respectively). Most of the low amplitude structures in the basin, generally trending north-easterly to north-westerly, are the result of reactivation of older basement structures in the underlying Drummond and Adavale Basins. Tectonic events were dominantly compressional resulting in uplift and erosion of parts of the basin during the Late Permian and Triassic. A regional south-westerly tilt was later imposed due to downwarping of the overlying Eromanga Basin, which is up to 1200 m thick over the Galilee strata. Sedimentation in the Galilee Basin was dominated by fluvial to lacustrine (and in part glacial) depositional systems. This resulted in a sequence of sandstones, mudstones, siltstones, coals and minor tuff in what was a relatively shallow intracratonic basin. The entire Galilee sequence is saturated with good to excellent quality fresh water in both the Permian and Triassic strata (Hawkins, unpublished) with probable recharge from the north-east into the outcropping Triassic reservoirs. Sediment composition is mixed as a result of a variety of provenances including older sedimentary rock, metasediments and other metamorphic rocks, granites, volcanics and direct volcanic input (tuffs). Climate varied from glacial to warm and humid to temperate. Forty years or more of exploration in the Galilee Basin has failed to discover any economic accumulations of hydrocarbons, despite the presence of apparently good to very good reservoirs and seals in both the Permian and Triassic sequence. Further geological study and in particular the interpretation of seismic data is required to increase the understanding and assess the quality of the basin for CO2 storage including; fully assessing reservoirs, seals and trapping mechanisms; estimating storage capacity; and addressing issues such as the presence of a potentially large fresh water resource.

This report is part of the results of a study into the potential for the geological storage of carbon dioxide within the Triassic Formations of the Galilee Basin in central Queensland carried out in Geoscience Australia on behalf of the CO2CRC. A review of the geological potential of the area has been issued as a separate report (Marsh et al., 2008) and this document describes the construction of a static geological model of one of the potential reservoirs in one area of the basin, while the results of a preliminary dynamic simulation study based on this model will be presented in a separate report by the reservoir engineer Yildiray Cinar of UNSW.

A geomechanical assessment of the Naylor Field, Otway Basin has been undertaken by the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) to investigate the possible geomechanical effects of CO2 injection and storage. The study aims to: - further constrain the geomechanical model (in-situ stresses and rock strength data) developed by van Ruth and Rogers (2006), and; - evaluate the risk of fault reactivation and failure of intact rock. The stress regime in the onshore Victorian Otway Basin is: - strike-slip if maximum horizontal stress is calculated using frictional limits, and; - normal if maximum horizontal stress is calculated using the CRC-1 leak-off test. The NW-SE maximum horizontal stress orientation (142ºN) determined from a resistivity image log of the CRC-1 borehole is broadly consistent with previous estimates and verifies a NW-SE maximum horizontal stress orientation in the Otway Basin. The estimated maximum pore pressure increase (Delta-P) which can be sustained within the target reservoir (Waarre Formation Unit C) without brittle deformation (i.e. the formation of a fracture) was estimated to be 10.9 MPa using maximum horizontal stress determined by frictional limits and 14.5 MPa using maximum horizontal stress determined using CRC-1 extended leak-off test data. The maximum pore pressure increase which can be sustained in the seal (Belfast Mudstone) was estimated to be 6.3 MPa using maximum horizontal stress determined by frictional limits and 9.8 MPa using maximum horizontal stress determined using CRC-1 extended leak-off test data. The propensity for fault reactivation was calculated using the FAST (Fault Analysis Seal Technology) technique, which determines fault reactivation propensity by estimating the increase in pore pressure required to cause reactivation (Mildren et al., 2002). Fault reactivation propensity was calculated using two fault strength scenarios; cohesionless faults (C = 0; ? = 0.60) and healed faults (C = 5.4; ?= 0.78). The orientations of faults with high and low reactivation propensity are similar for healed and cohesionless faults. In addition, two methods of determining maximum horizontal stress were used; frictional limits and the CRC-1 extended leak-off test. Fault reactivation analyses differ as a result in terms of which fault orientations have high or low fault reactivation propensity. Fault reactivation propensity was evaluated for three key faults within the Naylor structure with known orientations. The fault segment with highest fault reactivation propensity in the Naylor Field is on the Naylor South Fault near the crest of the Naylor South sub-structure. Therefore, leakage of hydrocarbons from the greater Naylor structure may have occurred through past reactivation of the Naylor South Fault, thus accounting for the pre-production palaeo-column in the Naylor field. The highest reactivation propensity (for optimally-orientated faults) ranges from an estimated pore pressure increase (Delta-P) of 0.0 MPa to 28.6 MPa depending on assumptions made about maximum horizontal stress magnitude and fault strength. Nonetheless, the absolute values of Delta-P presented in this study are subject to large errors due to uncertainties in the geomechanical model. In particular, the maximum horizontal stress and rock strength are poorly constrained.

The Australian Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) is planning a pilot project to inject, store, and monitor carbon dioxide in a depleted gas field (Naylor Field) in the Otway Basin, Victoria, in Southeast Australia. Approximately 100,000 tonnes of CO2 are planned to be injected over a 2 year period in a new well to be located down dip of the existing crestal well. An accurate and detailed geological assessment and characterization is essential to the selection/evaluation of any potential carbon storage site, as this provides the inputs for the reservoir models that are needed to design the monitoring and verification programs. For the proposed Otway Basin Pilot Project, the stratigraphy and structure of the Early Cretaceous Waarre Formation in the Port Campbell Embayment has been studied. Detailed geological models for reservoir simulation have been established based on geological, geophysical and history matching studies. Particular emphasis has been placed on the Early Cretaceous Waarre Formation (the main regional and proposed injection reservoir) in the Naylor Field. Uncertainties in the geological model (based on good 3D seismic but poor well data) will be ultimately minimized through the drilling and logging of a new well and the re-logging of the existing well. Prior to this, there is a need to understand the geological uncertainties as they stand, so that an effective well location and well testing program can be defined. Based on limited palynological control (from neighboring wells) the Waarre Formation is not notably time transgressive within the study area; beyond this only a broad breakdown is possible. The Waarre Formation is divisible into units A, B, C and D, A being the oldest. Only the Waarre C reservoir unit is of immediate interest. From regional work it is interpreted that the top of unit B is associated with minor erosion and incision, prior to the onset of significant growth faulting associated with continental breakup. Initial Waarre C deposition is sandy incised valley fill deposits on this eroded surface. The configuration of these basal Waarre C deposits has been seismically mapped. Core interpretation establishes that subsequent Waarre C deposition occurred on a sandy low sinuosity fluvial braid plain. study area; although there are indications that the upper Waarre C was partially eroded prior to transgression of the overlying marine Waarre D unit. The Waarre C section is characterized by clean high permeability sandstones, interpreted as abandoned channel fill ~2m thick, within which there are thin shales. These shales form the only significant flow barriers within this upper unit; and appear to comprise less than 10% of the section, but mapping their distribution is difficult. Several PETREL reservoir models were created to capture the uncertainty and potential reservoir heterogeneity of the Waarre C in the Naylor Field; key parameters (for example: porosity, permeability, channel orientation, shale content, connectivity, and gradient of the top structure) have been systematically varied to provide the most likely and extreme cases for the subsequent reservoir simulation studies. The reservoir properties have been characterized through history matching of the well-head pressure and water-cut data over the 18-month production history of the well using systematic numerical simulation approaches. The results indicate that the reservoir has an average permeability of 500-1000 mD, the original gas-water contact was at 2020 meters depth and that there was a significant aquifer support to the reservoir. This reservoir characterization and history matching study has provided additional and essential knowledge of the field and helped to constrain the injection location. The study establishes a sensible current reservoir condition, which will subsequently be used as the initial condition in the simulation of CO2 injection in the depleted gas field.

This invited contribution reviews applications of small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) to study the microstructure of sedimentary and igneous rocks in the last two decades. It is demonstrated how SANS can be used to explore the microstructure of rocks and help gain insights into internal specific surface area, porosity, pore size distribution, mercury intrusion porosimetry, compaction, subsurface generation of oil and gas, adsorption of gases, imbibition of water, distribution of crystalline precipitates and the microstructural effects of heat treatment. The article is intended to provide both a comprehensive introduction for newcomers to the subject and a reference text for those already familiar with small angle scattering techniques. Individual sections are self-contained and can be read in isolation.The article includes a review of theoretical results, worked examples, description of experimental procedures, examples of interpreted data for various types of rocks and references to original work.

GA contribution to CO2CRC. Report describes the work done to create a PETREL model of the Naylor Field proposed injection reservoir; eighteen appendicies.