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.

Underground gas storage (UGS) facilities provide a wealth of information, which can be used to better understand various aspects of CO2 storage in depleted reservoirs. In some cases UGS facilities can provide important site specific information for carbon storage projects that are planned in similar formations in close proximity. In this paper, we discuss the various ways in which UGS facilities can be used to extract important information, and when possible we draw upon information from the Iona gas storage facility in Australia's Otway basin. The Iona facility is located 20 km away from the CO2CRC Otway Project, in which CO2 65445 tonnes of 77 mole% carbon dioxide, 20 mole% methane and 3 mole% other gas components (containing about 58000 tonnes of carbon dioxide) was injected into the Waarre C formation over a 17 month period. In this paper, we compare the factors that control CO2 seal capacity and discuss how UGS facilities can provide information on sustainable column heights either limited by faults or by cap rocks. We also present dynamic modeling results in which information is gained regarding injectivity, pressure evolution of the reservoir, storage capacity and maximum fluid pressures sustained by the faults. Understanding such parameters is important for the safe operation of any carbon storage project, be it on a demonstration or industrial scale.

Poster for 2008 CO2CRC Symposium.

The release of fluid to the seabed from deeper sources is a process that can influence seabed geomorphology and associated habitats, with pockmarks a common indicator. In May 2012, Geoscience Australia led a multidisciplinary marine survey in Joseph Bonaparte Gulf, to facilitate an assessment of the potential for fluid leakage associated with geological storage of CO2 at depth within the Petrel Sub-basin. Multibeam bathymetry and backscatter mapping (652 km2), combined with acoustic sub-bottom profiling (655 line-km) and geomorphological and sediment characterisation of the seabed was undertaken. Seabed geomorphic environments identified from 2 m resolution bathymetry include carbonate banks and ridges, palaeochannels, pockmark fields and fields of low amplitude hummocks. This paper focuses on pockmarks as indicators of fluid seepage from the subsurface. Three principal pockmark morphologies (Type I, II and III) are present with their distribution non-random. Small unit (Type I) depressions occur on plains and in palaeochannels, but are most commonly within larger (Type II) composite pockmarks on plains. Type III pockmarks, intermediate in scale, are only present in palaeochannels. The timing of pockmark formation is constrained by radiocarbon dating to 14.5 cal ka BP, or later, when a rapid rise in sea-level would have flooded much of outer Joseph Bonaparte Gulf. Our data suggest the principal source of fluids to the seabed is from the breakdown of organic material deposited during the last glacial maxima lowstand of sea-level, and presently trapped beneath marine sediments. These results assist in ameliorating uncertainties associated with potential CO2 storage in this region.

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 sediment oxygen demand measurements undertaken on seabed sediments (0-2 cm).

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 chlorophyll a, b, c and phaeophytin a conentrations in the upper 2 cm of seabed sediments.

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 total sediment metabolism, bulk carbonate and mineral specific surface area measurements, and major and minor trace elements and carbon and nitrogen concentrations and isotopes in the upper 2 cm of seabed sediments.

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 porosity, total chlorin and chlorin index data from the upper 2 cm of seabed sediments.

The Petrel Sub-basin Marine Survey (GA0335/SOL5463) was undertaken in May 2012 by Geoscience Australia in collaboration with the Australian Institute of Marine Science (AIMS), as part of the Australian Government's National Low Emission Coal Initiative (NLECI). Its purpose was to acquire pre-competitive geophysical and biophysical data on shallow seabed environments within two targeted areas to support assessment of CO2 storage potential. The geophysical acquisition consisted of multibeam sonar mapping of sea floor morphology and multi-channel sub bottom profiling of the shallow sub surface geology. The aim of sub bottom profiling was to investigate regional seal breaches and potential fluid pathways by providing high resolution images connecting the sea floor map to regional seismic reflection data acquired concurrently in the area. The sub bottom profiler data were acquired aboard the AIMS research vessel (RV) Solander along 51 lines, totalling 654 line km in the Petrel Sub-basin of the Bonaparte Basin. Acquisition employed a Squid 2000 sparker as the source and a 24 channel Microeel streamer for the receivers. Group interval was 3.125 m and shot interval 6.25 m, resulting in 6 fold data. Record length was 500 ms with a sample interval of 0.25 ms. Some problems in acquisition needed to be addressed in processing. Firstly, sea conditions were far from smooth for most of the voyage. Obvious relative motion occurred between the source and the streamer, and along the streamer itself, due to the ocean swell. In some cases, acquisition commenced while the vessel was still turning onto the line and the streamer was not straight in line behind the stern. Finally, malfunction of the sparker on some half dozen lines resulted in gaps in the coverage, which could not be filled in later, due to bad weather reducing the time for the survey. Multichannel seismic reflection processing was able to compensate for some of the limitations of sparker acquisition. Mutes and filters were necessary to remove the worst of the noise, including leaked timing pulse and swell noise. Surface related multiple elimination (SRME) successfully attenuated the water bottom and later multiples. Non surface consistent trim statics were able to correct for the relative motion of the sparker and the streamer, thereby allowing alignment of reflections prior to stack, which improved the signal to noise. Minimum entropy deconvolution was a critical step in both suppressing ghosting and enhancing latent high frequencies in the data, thus improving the resolution. Migration was necessary to correctly image small channels by collapsing diffractions. Finally tidal static corrections were essential to remove mis-ties in high frequency data. The processing stream has been well documented, along with scripts employed to handle the large amount of data efficiently and consistently. This record is a manual for a much more rigorous way of processing multi-channel sparker data, and details a work flow that can be implemented within Geoscience Australia and used for future surveys. The final migrated seismic data proved to be very high resolution, allowing delineation of multiple episodes of channelling in the top 100 m of sediment. Comparison of the sub bottom profiles with older regional seismic reflection data showed just how much more detail is available in the region critical for mapping deeper faults and fluid pathways to features on the sea floor. Acquisition and processing of the sub bottom profiler data surpassed the survey expectations.

This report details the suitability of two identified sites in the Browse Basin for the geological storage of carbon dioxide: the Carbine Ponded Turbidite and the Leveque Shelf long migration dissolution trap. Detailed site assessments were completed by undertaking detailed geophysical interpretation of the top and base of each site, combined with a comprehensive structural, stratigraphic and sedimentological analysis, in order to construct a series of static 3D reservoir models for each potential storage site. These were submitted for CO2 injection simulation in order to better estimate the potential storage capacity, the potential injectivity volumes, and identify any containment-related issues of each site. Therefore this reports aims to provide technical recommendations regarding the viability of the long-term geological storage of CO2 in the Browse Basin.