VGP Technical Report 67 - Well formation tops, 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: As part of the Victorian Gas Program (VGP), the Geological Survey of Victoria (GSV) is studying petroleum systems components (reservoir, seal and source), to assess the hydrocarbon prospectivity of the Victorian Otway Basin and estimate the potential for further onshore and offshore discoveries within Victoria’s jurisdiction. Formation tops are depths in the subsurface at which geological units or formations are intersected; usually in wells and boreholes drilled to understand the geology or a resource such as petroleum or groundwater. Well formation tops are important as they provide the evidence to constrain seismic interpretation, mapping and modelling. In this study, legacy formation tops from 271 petroleum wells and boreholes across the Victorian Otway Basin were compiled, reviewed, and reinterpreted to define a single consistent set of regional formation tops. Formation tops from legacy GSV studies such as the Victorian Initiative for Minerals and Petroleum and from well completion reports were used as a starting point for the interpretation. Wells and boreholes deeper than 500 metres with good quality wireline log data were prioritised. Where there were data gaps, wells and boreholes with shallower total depths were included in the data set. Analysis of wireline log responses and existing tops were integrated with new VGP analysis including palynology (Charles et al., 2019), chemostratigraphy (Forbes et al., 2020), seismic interpretations (Romine et al., 2020) and a review of the Crayfish Subgroup (Eid et al., 2021a). Results from the examination of core and cuttings held at the Werribee Drill Core Library were also integrated along with stratigraphic and lithological descriptions from well completion reports. The analyses have resulted in an updated set of regional well formation tops for the onshore and offshore Victorian Otway Basin (Attachment A1). Further refinements at a local scale may be possible if new data becomes available. Bibliographic reference: Eid, R., Herley, S.S., Vujovic, A. & Guzel, M., 2021. Well formation tops, Otway Basin, Victoria. VGP Technical Report 67. Geological Survey of Victoria, Department of Jobs, Precincts and Regions, Melbourne, Victoria. The downloadable version of this report is supplied in PDF format (4.5 MB) & Att A1 (XLSX 184 KB). Related products:
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