VGP Technical Report 39 - Regional velocity modelling and depth conversion, Otway Basin.
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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 the Otway Basin’s petroleum systems components (reservoir, seal and source), to assess its petroleum prospectivity and to estimate the potential for further conventional gas discoveries onshore and offshore within Victoria’s jurisdiction. A velocity model was built to convert time surfaces to depth as part of the Otway Basin three- imensional (3D) geological framework model (Romine et al., 2020). Further work was required to extend the model across the Penola Trough in South Australia and south to the base of the continental slope offshore so that these key areas could be included in petroleum systems analysis. This new model will ensure that all available seismic interpretations are depth converted for use in petroleum systems modelling across the full extent of the VGP study area and over known hydrocarbon accumulations and associated source rocks onshore and offshore. These key areas are important to petroleum systems modelling. Each area has been identified as either: a) having potential to contribute to gas accumulations within the Victorian part of the Otway Basin; b) an analogue for significant Otway Basin petroleum system components; or c) a distal element of an active petroleum system in the Otway Basin. This updated velocity model was built using a single best fit depth of burial velocity equation derived from well data to closely approximate the vertical seismic velocities across the study area. This approximation of the velocity field was then modified using direct measurement at wells to match the velocity at each well location. This study provides a relatively simple and robust methodology for later refinement and extension of the velocity model as required for future basin analysis. Bibliographic reference: Dunne, J. & Boyd, M., 2020. Regional velocity modelling and depth conversion, Otway Basin. Victorian Gas Program Technical Report 39. Geological Survey of Victoria. Download: The downloadable version of this report is supplied in PDF format (19 MB) & Att A1 (ZIP 319 MB). | ||||||
