There remains considerable uncertainty regarding the location, timing and availability of CO2 storage sites in both southeast Queensland and New South Wales. In New South Wales, the main issues relate to the lack of recent or reliable valid geological information that would permit a complete and comprehensive evaluation. Some sedimentary basins appear to contain potential storage reservoirs although they have low permeabilities, and are therefore likely to have low injection rates. In southeast Queensland, recent work has indicated that in some parts of the Bowen and Surat basins CO2 storage is likely to compete with other resources such as groundwater and hydrocarbons. However, current research on the potential storage in deeper saline formations in the southern and western Bowen Basin has provided encouraging results. Storage in deeper stratigraphic units in the central western part of the basin will rely on injection in low permeability formations, and more correlation work is required to define generally narrow storage targets. The Wunger Ridge, in the southern Bowen Basin, however, has promise with both significant storage potential and relatively low geological risk. One area in which there is some potential in both New South Wales and southeast Queensland is CO2 storage in coal seams, as close technical and economic relationships exist between coal bed methane (CBM) field development and operations and CO2 storage. Substantial collaborative research is still required in this area and is currently a focus of the CO2CRC activities

Sampling, prior to CO2 injection at the CO2CRC Otway Project, southeastern Victoria at the end of 2007 early 2008, provided a stocktake of the molecular and isotopic (carbon and hydrogen) compositions of the subsurface hydrocarbon and non-hydrocarbon gases (and heavier hydrocarbons) at, and in close proximity to, the injection site. This baseline study is also fundamental to the assessment of present sub-surface petroleum components as natural tracers for injected gases arriving at the monitoring well. The CO2CRC Otway Project will use the CO2-rich natural gas (containing 79% CO2 and 20% methane) from the Buttress-1 well; totalling 100,000 tons of gas injected over 2 years. This gas mixture will be injected supercritically into sandstones of the CRC-1 well below the original gas-water contact at ~2000 m in the Waarre Formation. The depleted natural gas well at Naylor-1 is the monitoring well, situated 300 m updip of the injection well. Gas from the Waarre Formation in Naylor-1 observation well contains <1% CO2, which is isotopically depleted in 13C (13C -15.8) by 9 compared to CO2 (13C -6.8) in Buttress-1. Thus the carbon isotopes of CO2 can act as a primary natural tracer for monitoring purposes. Isotopically, the minimum detection limit would result from an increase of ~20 % in the CO2 concentration at Naylor-1 from the Buttress-derived CO2. On the other hand, the carbon and hydrogen isotopes of methane, wet gases and higher hydrocarbons are very similar between Buttress-1, CRC-1 and Naylor-1, requiring addition of external conservative tracers (Boreham et al., 2007) for the monitoring of hydrocarbon components. Although the content of liquid hydrocarbons in the gases is very low (<1%), there is the potential for supercritical CO2 extraction of these high molecular weight components (e.g. black oil in the Caroline-1 CO2 gas field and solid wax at the Boggy Creek CO2 production plant) that can be either advantageous (lubrication) or detrimental (clogging) to monitoring equipment at Naylor-1. The CRC-1 well provided an opportunity to collect downhole mud gases over many formations. Maximum total hydrocarbon concentration of 0.97 % occurred in the Waarre Formation Unit C. Surprisingly, a free gas zone in the overlying Flaxmans Formation had a lower maximum concentration (0.17 %). Carbon isotopes for the hydrocarbon gases from 1907 to 2249 mRT showed little downhole variation, while the 13C CO2 averaged -16, identical to CO2 at Naylor-1. Interestingly, the condensate recovered from a MDT in the Flaxmans Formation showed depletions in 13C for the C11 to C20 n-alkanes of up to 6 for n-C15 compared to n-alkanes of oils and condensates sourced from the Eumeralla Formation of the eastern Otway Basin (Boreham et al., 2004). Water washing is suspected at CRC-1 but is not expected to be a major factor affecting hydrocarbon compositions in the short term. The results of this subsurface petroleum audit have been pivotal in demonstrating the need for the addition of external tracers, especially for the hydrocarbon components, and provide an integral part of the near-surface, soil gas and atmospheric monitoring activities of the CO2CRC Otway Project. References Boreham, C.J., Hope, J.M., Jackson, P., Davenport, R., Earl, K.L., Edwards, D.S., Logan, G.A., Krassay, A.A., 2004. Gas-oil-source correlations in the Otway Basin, southern Australia. In: Boult, P.J., Johns, D.R., Lang, S.C. (Eds.), Eastern Australasian Basins Symposium II, Petroleum Exploration Society of Australia, Special Publication, pp. 603-627. Boreham, C.J., Underschultz, J., Stalker, L., Freifeld, B., Volk, H., Perkins, E., 2007. Perdeuterated methane as a novel tracer in CO2 geosequestration. In: Farrimond, P. et al. (Eds.), The 23rd International Meeting on Organic Geochemistry, Torquay, England 9th-14th September 2007, Book of Abstracts, 713-714.

In this paper, we present a high resolution study focussed mainly on the Gorgon field and associated Rankin Trend gas fields, Carnarvon Basin, Australia (Figure 1). These gas fields are characterized by numerous stacked reservoirs with varying CO2 contents and provide a relevant natural laboratory for characterizing CO2 migration, dissolution and reaction by looking at chemical characteristics of the different reservoirs (Figure 2). The data we present reveal interesting trends for CO2 mol% and -13C both spatially and with each other as observed by Edwards et al. (2007). Our interpretation of the data suggests that mineral carbonation in certain fields can be significant and relatively rapid. The Gorgon and Rankin Trend fields natural gases may therefore be a unique natural laboratory, which give further insights into the rates and extent of carbonate mineral sequestration as applied to carbon storage operations.

This paper briefly summaries how intrinsic uncertainties in reservoir characterization, at the proposed Otway Basin Naylor Field carbon-dioxide geo-sequestration site, were risk managed by a process of creation and evaluation of a series of geo-models (term to describe the geo-cellular geological models created by PETREL software) that cover the range of plausible geological possibilities, as well as extreme case scenarios. Optimization methods were employed, to minimize simulation run time, whilst not compromising the essential features of the basic geo-model. For four different Cases, 7 geo-models of the reservoir were created for simulation studies. The reservoir simulation study relies primarily on production history matching and makes use of all available information to help screen and assess the various geo-models. The results suggest that the bulk reservoir permeability is between 0.5 - 1Darcy, the original gas-water-contact was about 2020 mSS and there is a strong aquifer drive.

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.

Many industries and researchers have been examining ways of substantially reducing greenhouse gas emissions. No single method is likely to be a panacea, however 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. In Australia geological sequestration has been the subject of research for the last 2? years 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. 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.

No abstract available

The study provides a comprehensive analysis of the natural gases from the Bonaparte, Browse, Carnarvon and Perth basins (in 4 modules). Geochemical analyses for the molecular and carbon isotope composition were performed on 96 gases and associated liquids, and these data are interpreted in a geological context. Additional non-exclusive data from the AGSO database have been used for correlation/interpretation purposes. The study addresses factors influencing the composition of gaseous and other light hydrocarbons in natural gas (and associated oil accumulations) including; - primary source and maturity controls, - secondary alteration processes, e.g. migration fractionation, water washing, biodegradation, and - multiple charge histories, including deep dry gas inputs.

The middle to lower Jurassic sequence in Australia's Surat Basin has been identified as a potential reservoir system for geological CO2 storage. The sequence comprises three major formations with distinctly different mineral compositions, and generally low salinity formation water (TDS<3000 mg/L). Differing geochemical responses between the formations are expected during geological CO2 storage. However, given the prevailing use of saline reservoirs in CCS projects elsewhere, limited data are available on CO2-water-rock dynamics during CO2 storage in such low-salinity formations. Here, a combined batch experiment and numerical modelling approach is used to characterise reaction pathways and to identify geochemical tracers of CO2 migration in the low-salinity Jurassic sandstone units. Reservoir system mineralogy was characterized for 66 core samples from stratigraphic well GSQ Chinchilla 4, and six representative samples were reacted with synthetic formation water and high-purity CO2 for up to 27 days at a range of pressures. Low formation water salinity, temperature, and mineralization yield high solubility trapping capacity (1.18 mol/L at 45°C, 100 bar), while the paucity of divalent cations in groundwater and the silicate reservoir matrix results in very low mineral trapping capacity under storage conditions. Formation water alkalinity buffers pH at elevated CO2 pressures and exerts control on mineral dissolution rates. Non-radiogenic, regional groundwater-like 87Sr/86Sr values (0.7048-0.7066) indicate carbonate and authigenic clay dissolution as the primary reaction pathways regulating solution composition, with limited dissolution of the clastic matrix during the incubations. Several geochemical tracers are mobilised in concentrations greater than found in regional groundwater, most notably cobalt, concentrations of which are significantly elevated regardless of CO2 pressure or sample mineralogy.

Geoscience Australia and CO2CRC have constructed a greenhouse gas controlled release reference facility to simulate surface emissions of CO2 (and other GHG gases) from an underground slotted horizontal well into the atmosphere under controlled conditions. The facility is located at an experimental agricultural station maintained by CSIRO Plant Industry at Ginninderra, Canberra. The design of the facility is modelled on the ZERT controlled release facility in Montana. The facility is equipped with a 2.5 tonne liquid CO2 storage vessel, vaporiser and mass flow controller unit with a capacity for 6 individual metered CO2 gas streams (up to 600 kg/d capacity). Injection of CO2 into soil is via a shallow (2m depth) underground 120m horizontally drilled slotted HDPE pipe. This is equipped with a packer system to partition the well into six CO2 injection chambers. The site is characterised by the presence of deep red and yellow podsolic soils with the subsoil containing mainly kaolinite and subdominant illite. Injection is above the water table. The choice of well orientation based upon the effects of various factors such as topography, wind direction, soil properties and ground water depth will be discussed. An above ground release experiment was conducted from July - October 2010 leading to the development of an atmospheric tomography technique for quantifying and locating CO2 emissions1. This technique will be applied to the first sub-surface experiment held in January-March 2012 in addition to soil flux surveys, microbiological surveys, and tracer studies. An overview of monitoring experiments conducted during the subsurface release and preliminary results will be presented. Additional CO2 releases are planned for late 2012 and 2013. Abstract for "11th Annual Conference on Carbon Capture Utilization & Sequestration" April 30 - May 3, 2012, Pittsburgh, Pennsylvania