To investigate and quantify main physical heat driving processes affecting the present‐day subsurface thermal field, we study a complex geological setting, the Northeast German Basin (NEGB). The internal geological structure of the NEGB is characterized by the presence of a relatively thick layer of Permian Zechstein salt (up to 5000 m), which forms many salt diapirs and pillows locally reaching nearly the surface. By means of three‐dimensional numerical simulations we explore the role of heat conduction, pressure, and density driven groundwater flow as well as fluid viscosity related effects. Our results suggest that the regional temperature distribution within the basin results from interactions between regional pressure forces as driven by topographic gradients and thermal diffusion locally enhanced by thermal conductivity contrasts between the different sedimentary rocks with the highly conductive salt playing a prominent role. In contrast, buoyancy forces triggered by temperature‐dependent fluid density variations are demonstrated to affect only locally the internal thermal configuration. Locations, geometry, and wavelengths of convective thermal anomalies are mainly controlled by the permeability field and thickness values of the respective geological layers. Introduction Geothermal energy is of growing interest to the current and future energy demand. Accordingly, geothermal installations for a sustainable energy supply are increasingly developed. To assure cost‐effective installations a quantitative reserve assessment is required. Measurements in boreholes and laboratory‐based investigations may give site‐specific information on the subsurface temperature. Available in numerous works, such as those of Schneider (1955), Carslaw and Jaeger. (W/m2) is the heat transfer rate in the n direction per unit area. Adobe acrobat 8 standard italiano singles. Chapter and the interested reader can find a fairly detailed exposition of this topic in. Are the passage of an electric current through a wire or busbar or a rear window. This information may be spatially combined by means of classical interpolation algorithms resulting in maps of the temperature distribution for large (hundreds of kilometers) areas. Due to drilling costs, only sparse temperature measurements are generally available thus making the reliability of the resulting interpolated temperature maps at least questionable. Interpolation techniques do not take into account any of the physical processes occurring in the Earth's interior that result in the measured temperatures. Moreover, such methods do not sufficiently integrate the effects of heterogeneous physical properties in the subsurface due to variations in lithology. On the other hand, a proper understanding and quantification of the different energy drivers is essential for an efficient exploration of the underground geothermal resource. Numerical models provide a powerful alternative to interpolation methods. On the basis of physical principle of energy conservation, results from numerical simulations provide essential information about active processes in the subsurface and the resulting temperature distributions. Field based temperature measurements may be used to validate/calibrate those models, thus resulting in more feasible temperature predictions compared with interpolated temperature maps. In this paper we focus on three‐dimensional numerical models of the regional present‐day subsurface temperature field within a complex geological setting, the Northeast German Basin (NEGB). In the last two decades, the NEGB has been the target of an increasing number of studies aiming at revealing its tectonic evolution and its internal structure [;; ]. Geologically, the sedimentary succession of the basin is characterized by the presence of a thick sequence of Zechstein salt. The latter has different physical properties than other sedimentary rocks. In particular, rock salt shows thermal conductivity values two or three times higher than those typical of other sedimentary rocks [ ]. This difference in thermal conductivity has the potential to cause positive thermal anomalies near major salt structures. ![]() At the same time, rock salt is impervious to fluid flow. Those aspects make the NEGB an interesting “natural laboratory” for geothermal exploration. Accordingly, several studies have been carried out to investigate the geothermal potential of the basin. Three‐dimensional crustal scale conductive simulations were carried out. They related modeled local thermal variations within the basin to sharp gradients in thermal conductivity between salt and adjacent sedimentary rocks. Integrated a detailed configuration of the crust along a predefined two‐dimensional cross section along the basin. Their model additionally considered a simplified configuration of the lithospheric mantle constrained by seismic data as basal boundary condition for their thermal simulations. They found a relative good agreement between observed and modeled surface heat flow values as triggered by heterogeneities considered in their deeper crustal model.
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