VGP Technical Report 28 - A static geological model of the Croft gas field, 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 is being investigated as part of the Victorian Gas Program (VGP). There are currently three depleted gas fields used for UGS in Victoria. These sites are in the Port Campbell area in the onshore Otway Basin. 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 in the onshore Otway Basin. Six sites (depleted gas fields) were selected through a ranking process (Bagheri, 2019) for static and dynamic modelling. The sites are Croft, Fenton Creek, McIntee, Mylor, Penryn and Tregony. This report details how the 3D static geological model of the Croft gas field was built using PETRELTM software following the static modelling workflow (SEAL Energy 2020a). Three structural surfaces were used to model the Croft gas field: the top of the Belfast Mudstone, top of the Waarre Formation and top of the Eumeralla Formation. These represent the top of the seal, and the top and base of the reservoir, respectively. Zone modelling was performed to capture the structural features between these surfaces, including the Flaxman Formation and Waarre Formation units B and A. The model was then populated with reservoir properties following two different methods, to provide the dynamic simulators with a suite of static models to carry out fluid flow simulations. For each approach, porosity, permeability and water saturation was calculated from well cores and wireline logs to allow for volumes of the original gas in place to be calculated to assist in understanding the storage capacity of the Croft gas field during dynamic simulation as part of the Underground Gas Storage project. The final static model indicated that original gas in place volumetrics range from 2.7 to 8.5 Bcf for the two model types. A portion of this volume (roughly 0.2 Bcf) remains in the field as attic gas following production. Bibliographic reference: SEAL ENERGY, 2020. A static geological model of the Croft gas field, Onshore Otway Basin, Victoria. Victorian Gas Program Technical Report 28. Geological Survey of Victoria. Download: The downloadable version of this report is supplied in PDF format (63.6 MB) & Att A1 (ZIP 79.2 MB). Related products: | ||||||
