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

As part of the National CO2 Infrastructure Plan (NCIP) Geoscience Australia is undertaking evaluation of the Gage Sandstone and the overlying South Perth Shale for the long-term storage of CO2. Initial assessment of the seismic data identified widespread fault reactivation and seismic anomalies potentially indicating hydrocarbon seepage. Some of the seismic anomalies clearly correlate with reactivated faults, but not all of them. The study highlights the importance of developing a detailed understanding of spatial variability in seal quality and history of fault reactivation both for petroleum exploration and CO2 storage assessments.

The 2011 United Nations climate change meeting in Durban provided an historic moment for CCS. After five years without progress, the Cancun Decision (2010) put in place a work program to address issues of concern before CCS could be included under the Kyoto Protocol's Clean Development Mechanism (CDM) and so allow projects in developing countries to earn Certified Emission Reductions (CERs). The program - consisting submissions, a synthesis report and workshop - concluded with the UNFCCC Secretariat producing draft 'modalities and procedures describing requirements for CCS projects under the CDM. The twenty page 'rulebook' provided the basis for negotiations in Durban. The challenging negotiations, lasting over 32 hours, concluded on 9th December with Parties agreeing to adopt final modalities and procedures for CCS under the CDM. These include provisions for participation requirements (including host country regulations), site selection and characterisation, risk and safety assessment, monitoring, liabilities, financial provision, environmental and social impact assessments, responsibilities for long term non-permanence, and timing of the CDM-project end. A key issue was the responsibility for any seepage of CO2 emissions in the long-term (non-permanence). The modalities and procedures separate responsibility for non-permanence from the liability for any local damages resulting from operation of the storage site. In relation to the former, they allow for the host country to determine the responsible entity, either the host country or the country purchasing the CERs. Note that a CER which incorporates responsibility for seepage will be less attractive to buyers. Thus a standard is established for managing CCS projects in developing countries, which will ensure a high level of environmental protection and is workable for projects. It sets an important precedent for the inclusion of CCS into other support mechanisms.

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.

Between March 2008 and August 2009, 65,445 tonnes of ~75 mol% CO2 gas were injected in a depleted natural gas reservoir approximately 2000 m below surface at the Otway project site in Victoria, Australia. Groundwater flow and composition were monitored biannually in 2 near-surface aquifers between June 2006 and March 2011, spanning the pre-, syn- and post-injection periods. The shallow (~0-100 m), unconfined, porous and karstic aquifer of the Port Campbell Limestone and the deeper (~600-900 m), confined and porous aquifer of the Dilwyn Formation contain valuable fresh water resources. Groundwater levels in either aquifer have not been affected by the drilling, pumping and injection activities that were taking place, or by the precipitation increase observed during the project. In terms of groundwater composition, the Port Campbell Limestone groundwater is fresh (electrical conductivity = 801-3900 ?S/cm), cool (temperature = 12.9-22.5 °C), and near-neutral (pH 6.62-7.45), whilst the Dilwyn Formation groundwater is fresher (electrical conductivity 505-1473 ?S/cm), warmer (temperature = 42.5-48.5 °C), and more alkaline (pH 7.43-9.35). Evapotranspiration and carbonate dissolution control the composition of the groundwaters. Comparing the chemical and isotopic composition of the groundwaters collected before, during and after injection shows either no sign of statistically significant changes or, where they are statistically significant, changes that are generally opposite those expected if CO2 addition had taken place. The monitoring program demonstrates that the physical and chemical integrity of the groundwater resources has been preserved in the area.

This 2D deep crust seismic reflection survey is part of the joint project between the Geological Survey of Western Australia and Geoscience Australia and is a base study of the South Perth Basin linked to possible future geo-sequestration in the region. It consists of recording seismic signals down to 8 seconds two-way-time depth to image the rock layers below the earths surface. This geophysical method allows the upper crust to be imaged and assists in providing an understanding of the crustal architecture of the study region. Terrex Seismic, a sub-contractor, undertook the geophysical data acquisition. The data were processed to produce industry standard 2D land seismic reflection data. Raw data for this survey are available on request from clientservices@ga.gov.au

No abstract available

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 precipitation 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 North West Shelf. The gas data we present here display clear trends for CO2 abundance (mole %) and %- C CO2 both areally and vertically. 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 indicates that the late stage carbonate cements are related to the CO2 in the natural gases. The results suggest that a certain amount of CO2 may be sequestered in mineral form over short migration distances of the plume.

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to Autonomous Underwater Vehicle (AUV) still image data acquired during survey GA0345/GA0346/TAN1411. Following mapping with the shipboard multibeam, higher-resolution multibeam data were acquired in targeted areas using a Kongsberg Simrad EM2000 system mounted to the Fugro Echo Surveyor V (ES-5) AUV. This instrument had a depth rating of 3000 m, and surveyed the seafloor according to a pre-programmed mission plan. The AUV was fitted with a camera and light system designed to produce images of equal width and height (in the context of this survey, the images comprised 8 m by 8 m of seafloor). The equipment consisted of a light sensitive NEO 11 Megapixel 35 mm monochrome CCD (4008 x 2672) camera and two LED panels, each comprising 360 LEDs. High-resolution multibeam bathymetric data was collected together with side scan sonar and sub bottom profile data at an elevation of 30 m above the seafloor, and at line spacing's of 100 m. Overlapping high-resolution still photographs (captured every second) were then acquired on the survey lines at an elevation of 8 m above the seafloor. The AUV was equipped with an advanced real-time Aided Inertial Navigation System, which calculated the position, velocity and altitude of the vehicle and a HiPAP 500 USBL system was used to acoustically position the AUV. Underwater imagery was collected from two AUV missions in study Areas 3 and 4. During the 2nd AUV mission on 22 October, the vehicle encountered an obstruction on the seabed and became trapped despite commencing an emergency ascent sequence. The AUV was subsequently recovered from the seabed during salvage operations incorporated into the ROV phase of survey operations. A total of 24 877 still images were acquired in Area 3 and 20 743 in Area 4 over 58 and 56 line kilometres, respectively. Still images (.jpg files) are located in folder 'TAN1411_AUV_STILLS' with sub-folders named according to gear code (AUV= Autonomous Underwater Vehicle), mission and study Area (e.g. AUV_M2_A3 = still images acquired during AUV mission 2 in Area 3). USBL (Ultra-short baseline) text files (`TileCam.idx) are located in each sub-folder and provide continuous navigational information on location, time (UTC) and depth of AUV still imagery transect lines.

A geomechanical assessment of the Naylor Field, Otway Basin, Australia has been undertaken to investigate the possible geomechanical effects of CO2 injection and storage. The study aims to evaluate the geomechanical behaviour of the caprock/reservoir system and to estimate the risk of fault reactivation. The stress regime in the onshore Victorian Otway Basin is inferred to be strike-slip if the maximum horizontal stress is calculated using frictional limits and DITF (drilling induced tensile fracture) occurrence, or normal if maximum horizontal stress is based on analysis of dipole sonic log data. The NW-SE maximum horizontal stress orientation (142 degrees N) determined from a resistivity image log is broadly consistent with previous estimates and confirms a NW-SE maximum horizontal stress orientation for the Otway Basin. An analytical geomechanical solution is used to describe stress changes in the subsurface of the Naylor Field. The computed reservoir stress path for the Naylor Field is then incorporated into fault reactivation analysis to estimate the minimum pore pressure increase required to cause fault reactivation (Pp) The highest reactivation propensity (for critically-oriented faults) ranges from an estimated pore pressure increase (Pp) of 1MPa to 15.7MPa (estimated pore pressure of 18.5-233. MPa) depending on assumptions made about maximum horizontal stress magnitude, fault strength,reservoir stress path and Biot's coefficient. The critical pore pressure changes for known faults at Naylor Field range from an estimated pore pressure increase (Pp) of 2MPa to 17MPa (estimated pore pressure of 19.5-34.5 MPa).