b'AEGC 2023Short abstractssensitivities of this configuration are similar to those of TE-modeintervals (Shipwreck and Sherbrook supersequences), especially MT data. Synthetic 2D modeling results across a conductivein the deep-water areas of the basin where generation is body demonstrate how the host conductivity and the locationpredicted to have ceased at the end of the Cretaceous. Towards of the base station affect the conductor response. The strongthe southeast, source rocks are generally shallower at present-sensitivity of the data to the conductivity structure at the baseday; additionally, this part of the basin was less affected by station results in inversion results being quite sensitive to theLate Cretaceous erosion, resulting in greater post-Cretaceous inversion start models used. hydrocarbon potential. There are areas where Upper Cretaceous source rocks generate hydrocarbons during the Cenozoic. Regular 2D inversion results of survey MobileMT data showThese are located 1) in the far outboard areas of the study area strong conductivity variations from line to line. For betterwhere isolated Cenozoic depocenters exist, and 2) in tilted fault model continuity multiple lines of data are joint inverted withblocks closer to the current shelf edge where they are positively an across-line smoothness constraint applied. MobileMT surveyinfluenced by the late burial of the Heytesbury and Whalers data from the Grindstone Copper-Nickel-Cobalt project, NewBluff supersequences. In the deep-water part of the basin, Brunswick indicate a strong correlation between conductivitywhere postulated source rocks are overmature prior to seal highs and magnetic anomalies. 2D inversions suggesteffectiveness, model results still predict hydrocarbon potential conductivity structures to be detected up to 1000-2000 mdue to the modelled slow migration of hydrocarbons through depth. Model results from a VMS exploration survey across themud-dominated intervals, charging potential traps later when Broken Evil prospect, Northern Ontario show good correlationseals are effective. The regional 2D PSM study represents with conductivity structures derived from a previous VTEMa framework for improved understanding of the dynamic survey, including the location of a suspected VMS body. evolution of the Otway Basin and its complex thermal and charge history. It provides an ideal basis for model refinements, The joint inversion of active-source and natural-fieldand additional sensitivity analyses.EM data.Daniel Sattel and Ken Witherly2 3D seismic feasibility study of Olympic Dam.1 EM SolutionsHeather Schijns 1 Jared Townsend1, David Haddow2, Kathy 2 Condor Consulting Ehrig2, Max Shawcross2, Cheryl Mifflin3, Alex Hao4 and Chi Chen4Active-source and natural-field EM data differ in their sensitivity1 BHP Group Limited to subsurface conductivity structures. Generally, the former2 BHP Olympic Dam offer higher spatial resolution and have a greater sensitivity3 FerVID to near-surface conductivities. The latter are more sensitive4 CGGto broader structures and, for MT data, offer deeper depthOlympic Dam is a world-class IOCG (iron-oxide copper gold) penetration. The applied joint inversion algorithm, based on 2Ddeposit located in Southern Australia, and is the flagship NFEM and 1D active-source EM codes, combines the strengthsdeposit for the IOCG deposit-style. It is one of the largest of both data sets, resulting in more reliable models. Further,known copper deposits and single largest uranium deposit in joint inversion allows for the galvanic distortion affecting MTthe world. Mineralisation at Olympic Dam is disseminated in data to be taken into account, and for MobileMT data thenature, and is hosted in hydrothermal breccia within Roxby electric reference field can be constrained better. Three NorthDowns Granite. Between the gradational nature of the contacts American case studies are discussed to demonstrate thebetween the iron-oxide rich breccia and the altered granite, and benefits of joint inversions: Dighem/ZTEM/MT data acquired forthe small-scale heterogeneity of the breccia itself, few apparent copper porphyry exploration, HeliTEM/ZTEM data for uraniumopportunities exist to generate coherent seismic reflectivity. and VTEM/MobilMT data for VMS exploration. The feasibility of hard rock seismic to effectively image IOCGs, and more broadly, disseminated mineralisation, has been Petroleum system modelling of the deep-water Otwayunclear to date, with few examples in the literature. In 2021, BHP Basin. undertook an in depth 3D surface and VSP seismic feasibility study of Olympic Dam. Utilising a physical property model that Oliver Schenk, Duplo Kornpihl, Emmanuelle Grosjean, Dianneincluded, for the first time, representative 3D geometry and Edwards, Christopher Boreham, Chris Nicholson, Merrie-Ellengeological variability at a 10x10x10m resolution, the feasibility Gunning, Tekena West and Alex Karvelas study allowed detailed examination of the impact of various Geoscience Australia acquisition and processing decisions on successfully imaging this complex geology. Here we present the feasibility study The Otway Basin is a broadly northwest-southeast trendingprocess and results.basin and forms part of a rift system that developed along Australias southern margin. It is an established hydrocarbon province with onshore and shallow-water offshore discoveries.3D inversion of Airborne EM using airborne magnetics The outboard deep-water Otway Basin, in water depths greateras a structural guide.than 500 m, is comparatively underexplored and considered a frontier area. Following the completion of a basin-wide seismicCarsten Scholl, Marianne Parsons and Tom Kimuraprogramme in 2020 and insights from revised regional seismicCGGinterpretation, we undertook a comprehensive 2D petroleum system modelling (PSM) study, integrating these data andThe Airborne Electromagnetic (AEM) method has been widely findings. The modelling results indicate that hydrocarbonadapted in the mining industry to detect a large mineral generation is mainly controlled by burial of Upper Cretaceousdeposit with conductive material. Also magnetic data is usually 137 PREVIEW FEBRUARY 2023'