| Abstract |
Exploring geothermal energy in sedimentary basins is challenging due to complex geology, limited deep thermal data, and a historical focus on hydrocarbons. This study addresses this by integrating 3D geological modelling and heat flow simulation of a section of the onshore Gippsland Basin in southeastern Australia to better understand its thermal structure and identify suitable areas for geothermal development. Using Leapfrog Energy, we built a high-resolution (100 m) 3D geological model integrating topography and prior horizons interpreted from boreholes/wells, seismic, and gravity data. The model covers key stratigraphic units, including the Haunted Hills Formation, Tertiary coal units, Cenozoic sediments, and deeper basement rocks. Special attention was given to a Cenozoic sedimentary unit hosting a regional aquifer with potential for geothermal energy in the 30–70°C range. We mapped this unit’s spatial extent beneath a 61 × 73 km study region to estimate its groundwater storage capacity and heat-in-place. To explore heat movement, the upper 2.6 km of the model was imported into Underworld3, a thermal simulation tool. By assigning realistic rock properties and applying preliminary boundary temperature conditions, a steady-state temperature model of the subsurface was produced. The results revealed zones of elevated temperature, structurally focused heat flow, and areas where target temperatures can be reached at economical drilling depths. This workflow offers a powerful method for assessing geothermal resources using existing geological data and open-source modelling software, providing a foundation for further refinement, resource evaluation, well targeting, and the development of a geothermal energy industry in the Gippsland Basin. |