TY - JOUR A1 - Bauer, Klaus A1 - Moeck, Inga A1 - Norden, Ben A1 - Schulze, Alexander A1 - Weber, Michael H. A1 - Wirth, Holger T1 - Tomographic P wave velocity and vertical velocity gradient structure across the geothermal site Groß Schoenebeck (NE German Basin) : relationship to lithology, salt tectonics, and thermal regime N2 - Seismic wide-angle data were collected along a 40-km-long profile centered at the geothermal research well GrSk 3/90 in the Northeast German Basin. Tomographic inversion of travel time data provided a velocity and a vertical velocity gradient model, indicative of Cenozoic to Pre-Permian sediments. Wide-angle reflections are modeled and interpreted as top Zechstein and top Pre-Permian. Changes in velocity gradients are interpreted as the transition from mechanical to chemical compaction at 2-3 km depth, and localized salt structures are imaged, suggesting a previously unknown salt pillow in the southern part of the seismic profile. The Zechstein salt shows decreased velocities in the adjacent salt pillows compared to the salt lows, which is confirmed by sonic log data. This decrease in velocity could be explained by the mobilization of less dense salt, which moved and formed the salt pillows, whereas the denser salt remained in place at the salt lows. We interpret a narrow subvertical low-velocity zone under the salt pillow at GrSk 3/ 90 as a fault in the deep Permian to Pre-Permian. This WNW-ESE trending fault influenced the location of the salt tectonics and led to the formation of a fault-bounded graben in the Rotliegend sandstones with optimal mechanical conditions for geothermal production. Thermal modeling showed that salt pillows are related to chimney effects, a decrease in temperature, and increasing velocity. The assumed variations in salt lithology, density, and strain must thus be even higher to compensate for the temperature effect. Y1 - 2010 UR - http://www.agu.org/journals/jb/ U6 - https://doi.org/10.1029/2009jb006895 SN - 0148-0227 ER - TY - JOUR A1 - Cherubini, Yvonne A1 - Cacace, Mauro A1 - Scheck-Wenderoth, Magdalena A1 - Moeck, Inga A1 - Lewerenz, Björn T1 - Controls on the deep thermal field - implications from 3-D numerical simulations for the geothermal research site Groß Schönebeck JF - Environmental earth sciences N2 - The deep thermal field in sedimentary basins can be affected by convection, conduction or both resulting from the structural inventory, physical properties of geological layers and physical processes taking place therein. For geothermal energy extraction, the controlling factors of the deep thermal field need to be understood to delineate favorable drill sites and exploitation compartments. We use geologically based 3-D finite element simulations to figure out the geologic controls on the thermal field of the geothermal research site Gro Schonebeck located in the E part of the North German Basin. Its target reservoir consists of Permian Rotliegend clastics that compose the lower part of a succession of Late Carboniferous to Cenozoic sediments, subdivided into several aquifers and aquicludes. The sedimentary succession includes a layer of mobilized Upper Permian Zechstein salt which plays a special role for the thermal field due to its high thermal conductivity. Furthermore, the salt is impermeable and due to its rheology decouples the fault systems in the suprasalt units from subsalt layers. Conductive and coupled fluid and heat transport simulations are carried out to assess the relative impact of different heat transfer mechanisms on the temperature distribution. The measured temperatures in 7 wells are used for model validation and show a better fit with models considering fluid and heat transport than with a purely conductive model. Our results suggest that advective and convective heat transport are important heat transfer processes in the suprasalt sediments. In contrast, thermal conduction mainly controls the subsalt layers. With a third simulation, we investigate the influence of a major permeable and of three impermeable faults dissecting the subsalt target reservoir and compare the results to the coupled model where no faults are integrated. The permeable fault may have a local, strong impact on the thermal, pressure and velocity fields whereas the impermeable faults only cause deviations of the pressure field. KW - Thermal field KW - Coupled fluid and heat transport KW - Faults KW - Groß beta Schönebeck Y1 - 2013 U6 - https://doi.org/10.1007/s12665-013-2519-4 SN - 1866-6280 SN - 1866-6299 VL - 70 IS - 8 SP - 3619 EP - 3642 PB - Springer CY - New York ER - TY - JOUR A1 - Reiter, Karsten A1 - Heidbach, Oliver A1 - Schmitt, Douglas A1 - Haug, Kristine A1 - Ziegler, Moritz O. A1 - Moeck, Inga T1 - A revised crustal stress orientation database for Canada JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - The Canadian database on contemporary crustal stress has not been revised systematically in the past two decades. Here we present the results of our new compilation that contains 514 new data records for the orientation data of maximum compressive horizontal stress and 188 data records that were re-assessed. In total the Canadian stress database has now 1667 data records, which is an increase of about 45%. From these data, a new Canadian Stress map as well as one for the Province of Alberta is presented. To analyse the stress pattern, we use the quasi median on the circle as a smoothing algorithm that generates a smoothed stress map of the maximum compressive horizontal stress orientation on a regular grid. The newly introduced quasi interquartile range on the circle estimates the spreading of the data and is used as a measure for the wave-length of the stress pattern. The result of the hybrid wavelength analysis confirms that long spatial wavelength stress patterns (>= 1000 km) exist in large areas in Canada. The observed stress pattern is transmitted through the intra-plate regions. The results reveal that shorter spatial wave length variation of the maximum compressive horizontal stress orientation of less than 200 km, prevails particularly in south-eastern and western Canada. Regional stress sources such as density contrasts, active fault systems, crustal structures, etc. might have a significant impact in these regions. In contrast to these variations, the observed stress pattern in the Alberta Basin is very homogeneous and mainly controlled by plate boundary forces and body forces. The influence of curvature of the Rocky Mountains salient in southern Alberta is minimal. The present-day horizontal stress orientations determined herein have important implications for the production of hydrocarbons and geothermal energy in the Alberta Basin. (C) 2014 Elsevier B.V. All rights reserved. KW - Stress pattern KW - Tectonic stress KW - Canada KW - Alberta KW - Database KW - Circular statistics Y1 - 2014 U6 - https://doi.org/10.1016/j.tecto.2014.08.006 SN - 0040-1951 SN - 1879-3266 VL - 636 SP - 111 EP - 124 PB - Elsevier CY - Amsterdam ER -