• Energy Research

Hydrothermal systems are characterised by complex interactions between heat transfer, fluid flow, deformation, species transport and chemical reactions. Numerical models can provide quantitatively constrained information in regions where acquisition of new data is difficult or expensive thus providing a means for reducing risks, costs, and effort during targeting, production, and management of resources linked to hydrothermal systems. Here we show how numerical simulations of hydrothermal processes can be used to better understand coupled reactive transport in modern geothermal systems and in ancient hydrothermal ore deposits. We give examples based on the Enhanced Geothermal System at Soultz-sous-Forets in France, hydrothermal mineralisation at Mount Isa in Australia, and the geothermal resource at Hamburg-Allermohe in Germany.

AbstractThe general crustal structure of the Youanmi Terrane – a tectonic unit within the Neoarchean Yilgarn Craton – and its relationship to ore deposits are of major interest in Western Australia. To image geological structures, the Geological Survey of Western Australia in collaboration with Geoscience Australia acquired three deep crustal 2D seismic profiles over the region in 2010. In this study, we have reprocessed a 120km long section of one of the seismic profiles, line 10GA-YU1. We reprocessed the data with focus on shallow reflections down to 2 s (about 6km depth). A cross-dip analysis was performed to investigate the dip of the reflections in cross-line direction. The cross-dip analysis showed that there is no significant cross-dip influence, confirming that a 2D interpretation is a valid assumption for this dataset. The seismic image of the reflections was improved after applying dip-moveout correction. Finally, the reflections were migrated to their “true” locations in the subsurface. To better understand the physical properties of the subsurface, we also tried First Arrival Travel-Time Tomography. The tomography results show that low velocities correlate with shear zones and that high velocity zones are common where mineral deposits are located close to the surface.