VGP Technical Report 11 - A review of the preliminary Underground Gas Storage site ranking Onshore Otway Basin, Victoria.
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Product description:About the Victorian Gas Program: The Victorian Gas Program (VGP) is a comprehensive science-led program, incorporating geoscientific and environmental research to assess the risks, benefits and impacts of potential onshore conventional gas exploration and production. The program is also investigating the potential for further discoveries of onshore conventional and offshore gas in the Otway and Gippsland geological basins and assessing the feasibility of additional onshore underground gas storage in depleted reservoirs around the Port Campbell area. The VGP includes an extensive, proactive and phased community and stakeholder engagement program, through which the results of the scientific studies are being communicated. Executive summary: The opportunity for further Underground Gas Storage (UGS) in depleted gas fields in the onshore Otway Basin has been investigated as part of the Victorian Gas Program (VGP). Buschkuehle et al. (2019) completed a preliminary ranking to assess the suitability of 13 depleted or unproduced gas fields (sites) for potential UGS. The purpose of this study was to review the preliminary ranking and refine data inputs to confirm the ranking results before proceeding with further detailed modelling studies as part of the Victorian Gas Program UGS project. The preliminary study used three criteria: capacity, injectivity and containment, to rank 13 potential UGS sites. The existing UGS fields (Iona, Wallaby Creek and North Paaratte) were included in the ranking to verify the methodologies applied. The results of the preliminary study indicated that the depleted gas fields Mylor, Tregony, McIntee and Penryn were the most prospective sites for further detailed technical studies, whilst Wild Dog Road, Lavers and Seamer were identified as the least prospective sites. The Geological Survey of Victoria (GSV) engaged SEAL Energy Pty Ltd (SEAL Energy) to carry out a suite of technical studies to investigate the potential for further underground gas storage at existing depleted gas fields and known unproduced fields in the onshore Otway Basin. The first study carried out by SEAL Energy is this review of the preliminary ranking. The results of this study confirmed that the preliminary study was fit-for-purpose. Refinement of capacity and injectivity values were undertaken to resolve inconsistencies in the data sets used for the preliminary ranking. In addition, the method applied in this assessment did not consider containment as all fields have successfully trapped gases over geological time. For this study, injectivity and capacity were equally weighted. The results of this report confirm that McIntee and Mylor are the most suitable sites, whilst Tregony, Croft, Langley, Fenton Creek, Penryn and Seamer are suitable, with Grumby, Skull Creek, Wild Dog Road, Dunbar and Lavers ranked least suitable. On this basis, Mylor, McIntee, Tregony, Croft, Fenton Creek and Penryn are recommended for full static and dynamic modelling. Langley was discounted for further analysis as the high carbon dioxide content still present in the field would necessitate application of an additional modelling workflow to account for the carbon dioxide. Prior to geological modelling work on the top six ranked sites, to ensure consistency in field capacities, a probabilistic Original Gas in Place (OGIP) calculation for all sites will be completed. This will be based on geological structures determined by operators at the time of field discovery with probabilistic properties derived from a revised petrophysical analysis of field data and an additional study to review the Penryn field. Bibliographic reference: Bagheri, M., 2019. A review of the preliminary Underground Gas Storage site ranking Onshore Otway Basin, Victoria. Victorian Gas Program Technical Report 11. Geological Survey of Victoria. Department of Jobs, Precincts and Regions. Download: The downloadable version of this report is supplied in PDF format (1.6 MB) and accessible version (DOCX 953 KB). Related products:
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