Prospectivity and play analysis in the frontier Great Australian Bight: the benefits of a public domain data system and the application of traditional and new technologies
Ian Longley A and James Dirstein BA GIS-Pax Pty Ltd.
B Total Depth Pty Ltd.
The APPEA Journal 56(2) 579-579 https://doi.org/10.1071/AJ15085
Published: 2016
Abstract
The deep water portion of the Great Australian Bight remains an untested basin with the Gnarlyknots–1A well drilled in 2003 not penetrating deep enough to test the well’s targets within the Upper Cretaceous Ceduna Delta section. If an anoxic marine shale source system, that is an effective source in many parts of West Africa, is present beneath the delta, then this could supply a material oil charge into the numerous fault block structures identified on seismic data. With eight wells due to be drilled in the next few years, this area will be one of the most active exploration frontier settings in the region.
Since Australia has an open file system for technical data, the regional Flinders 2000 2D Marine seismic Interpretation report containing five regional Time structure maps is now in the public domain, as is the Gnarlyknots–1A well data and the raw seismic data from the Ceduna 3D survey acquired in 2012. These data were used to evaluate the untested Coniacian play interval with the construction of Reservoir Presence and quality, seal and charge relative probability maps made from various proxies that were then stacked to show areas of relative prospectivity. This traditional approach was supplemented by the an example showing pre-interpretation surfaces from the pre-Cenomanian portion of the 3D volume to help develop a better understanding of the potential prospectivity of deeper intervals not captured on the submitted open file maps. The workflow presented here suggests some parts of the Ceduna Sub Basin are significantly more prospective than others. Moreover, we demonstrate that even in frontier settings with minimal well data, pre-interpretation processing and simple play analysis together can be a useful and efficient approach for delivering significant insights into prospectivity. This workflow will ultimately promote more exploration thinking and activity in the future.
Ian Longley is a regional petroleum geologist with 30 years of experience. He has worked for Lasmo, Woodside, Shell, and Oil Search in various locations around the world. Ian has specialised in plate tectonic evolution, regional petroleum geology, play and prospect analysis, and the hunt for new exploration opportunities. He now runs the industry training course on the Petroleum Geology of SE Asia (www.pgsea.com), and has published extensively on regional petroleum geology. Ian is also working as a consultant. He is joint developer of the Player ArcGIS play analysis software, which is now used by more than 30 international exploration and production companies. Ian also builds multi-client Player Project evaluations of Australia’s North West Shelf basins with other consultants using public domain data. |
James Dirstein studied geology and geophysics at the University of Toronto, graduating in 1980. With more than 30 years of international experience in the oil industry—including the past 20 years as founder and director of Total Depth Pty Ltd—Jim has developed a diverse set of skills, working in a wide range of geological and corporate settings. Aside from his activities with Total Depth, Jim has helped with the commercialisation and application of many new technologies. Recently, this has included the refinement of a patent for a new airborne geophysical technique, a seisnetics-patented processing algorithm, and establishing Geoproxima Pty Ltd. Member: ASEG, SEG, PESA, AAPG, SEPM, EAGE. |
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