Influence of the Main Border Faults on the 3D Hydraulic Field of the Central Upper Rhine Graben

The Upper Rhine Graben (URG) is an active rift with a high geothermal potential. Despite being a well-studied area, the three-dimensional interaction of the main controlling factors of the thermal and hydraulic regime is still not fully understood. Therefore, we have used a data-based 3D structural model of the lithological configuration of the central URG for some conceptual numerical experiments of 3D coupled simulations of fluid and heat transport. To assess the influence of the main faults bordering the graben on the hydraulic and the deep thermal field, we carried out a sensitivity analysis on fault width and permeability. Depending on the assigned width and permeability of the main border faults, fluid velocity and temperatures are affected only in the direct proximity of the respective border faults. Hence, the hydraulic characteristics of these major faults do not significantly influence the graben-wide groundwater flow patterns. Instead, the different scenarios tested provide a consistent image of the main characteristics of fluid and heat transport as they have in common: (1) a topography-driven basin-wide fluid flow perpendicular to the rift axis from the graben shoulders to the rift center, (2) a N/NE-directed flow parallel to the rift axis in the center of the rift and, (3) a pronounced upflow of hot fluids along the rift central axis, where the streams from both sides of the rift merge. This upflow axis is predicted to occur predominantly in the center of the URG (northern and southern model area) and shifted towards the eastern boundary fault (central model area).

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Influence of fluid flow and heat transport on predictions of geothermal potentials in sedimentary layers of Hesse (Germany)

10.5194/egusphere-egu2020-4685 ◽

2020 ◽

Author(s):

Nora Koltzer ◽

Maximilian Frick ◽

Magdalena Scheck-Wenderoth ◽

Björn Lewerenz ◽

Kristian Bär ◽

...

Keyword(s):

Fluid Flow ◽

Heat Transport ◽

Thermal Model ◽

Transport Processes ◽

Heating Power ◽

Upper Rhine Graben ◽

Reservoir Temperature ◽

Rhine Graben ◽

Geothermal Potential ◽

Upper Rhine

For the sustainable utilization of deep geothermal resources it is essential to predict the exploitable potential thermal energy from the subsurface. One main parameter influencing the geothermal potential is the reservoir temperature that may vary locally or regionally in response to fluid flow and heat transport processes.This study aims at combining highly complex 3D thermo-hydraulic numerical simulations of heat transport and fluid flow with predictions of the geothermal potential for the application case of a hydrothermal doublet. Quantifying the influences of conductive, advective and convective heat transport mechanisms on the thermal field and moreover on the predicted heating power requires fundamental numerical investigations. We use the Federal State of Hesse in Germany as study area where heat transport processes have been quantified in recently published studies. There, the heterogeneous geology consists of outcropping Variscan Crust and up to 3.8 km and 1.8 km thick sedimentary deposits of the Upper Rhine Graben and the Hessian Depression, respectively. This geological complexity is expressed by areas of different hydraulic and thermal configurations: in the flat, but tectonically active Upper Rhine Graben high heat flow from below the graben sediments is in contrast to the variable topography of the Hessian Depression with low heat input from the Rhenohercynian Basement.The heating power in the three reservoir units (I) Cenozoic, (II) Buntsandstein and (III) Rotliegend is only predicted to be high in the Upper Rhine Graben. There the reservoir temperature is high enough and varies between 50 &#176;C in the convective thermal model of the Cenozoic reservoir and 170 &#176;C in the conductive thermal model of the Buntsandstein reservoir. Predicted low temperatures in the Hessian Depression lead to negligible low heating power, but as production mass flux is above ~6 kg s-1 investigations should continue to assess the geothermal potential for other applications like seasonal energy storage or low enthalpy geothermal utilization.

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Evolution and structure of the Upper Rhine Graben: insights from three-dimensional thermomechanical modelling

International Journal of Earth Sciences ◽

10.1007/s00531-004-0451-2 ◽

2004 ◽

Vol 94 (4) ◽

pp. 732-750 ◽

Cited By ~ 27

Author(s):

Michael Schwarz ◽

Andreas Henk

Keyword(s):

Three Dimensional ◽

Upper Rhine Graben ◽

Rhine Graben ◽

Upper Rhine

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A structural model from local earthquake tomography: Application to present-day tectonics of the Upper Rhine Graben

Global and Planetary Change ◽

10.1016/j.gloplacha.2007.03.008 ◽

2007 ◽

Vol 58 (1-4) ◽

pp. 270-286 ◽

Cited By ~ 2

Author(s):

Tristan Cornu ◽

Gideon Lopes Cardozo ◽

Sierd Cloetingh ◽

Fred Beekman

Keyword(s):

Structural Model ◽

Upper Rhine Graben ◽

Local Earthquake Tomography ◽

Rhine Graben ◽

Local Earthquake ◽

Upper Rhine

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Three-dimensional basin analysis of the Heidelberg Basin, Upper Rhine Graben

Quaternary International ◽

10.1016/j.quaint.2012.08.1640 ◽

2012 ◽

Vol 279-280 ◽

pp. 484

Author(s):

David Tanner

Keyword(s):

Three Dimensional ◽

Basin Analysis ◽

Upper Rhine Graben ◽

Rhine Graben ◽

Upper Rhine

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Anatomy and kinematics of oblique continental rifting revealed: A three-dimensional case study of the southeast Upper Rhine graben (Germany)

AAPG Bulletin ◽

10.1306/02180300153 ◽

2003 ◽

Vol 87 (7) ◽

pp. 1105-1121 ◽

Cited By ~ 26

Author(s):

Jan H. Behrmann ◽

Oliver Hermann ◽

Mathias Horstmann ◽

David C. Tanner ◽

Guillaume Bertrand

Keyword(s):

Three Dimensional ◽

Dimensional Case ◽

Upper Rhine Graben ◽

Continental Rifting ◽

Rhine Graben ◽

Upper Rhine

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3D Modelling of the Northern Upper Rhine Graben Crystalline Basement by Joint Inversion of Gravity and Magnetic Data

10.5194/egusphere-egu21-477 ◽

2021 ◽

Author(s):

Matthis Frey ◽

Sebastian Weinert ◽

Kristian Bär ◽

Jeroen van der Vaart ◽

Chrystel Dezayes ◽

...

Keyword(s):

High Resolution ◽

Heat Transport ◽

Joint Inversion ◽

Transport Processes ◽

Crystalline Basement ◽

Magnetic Data ◽

Moho Depth ◽

Upper Rhine Graben ◽

Rhine Graben ◽

Upper Rhine

The crystalline basement of the Upper Rhine Graben presents an attractive target for deep geothermal projects due to its favourable temperatures and its high potential as a fractured and faulted reservoir system. It is already exploited at several sites, e.g. Soultz-sous-For&#234;ts or Landau, and further projects are currently planned or under development. The crystalline units are furthermore the main source of radiogenic heat production and thus, together with the shallow Moho depth and convective heat transport along large fault zones, significantly contributing to the crustal temperature field. For these reasons, we developed the most detailed 3D geological model of the basement in the northern Upper Rhine Graben to date within the Interreg NWE DGE-ROLLOUT and Hesse 3D 2.0 projects. Due to the small number of very deep boreholes as well as seismic profiles reaching the basement beneath the locally more than 5 km thick sedimentary cover, we additionally used high-resolution magnetic and gravity datasets. In contrast to common deterministic modelling approaches, we performed a stochastic joint inversion of the geophysical data by applying a Monte Carlo Markov Chain algorithm. This method generates a large set of random but valid models, which enables a statistical evaluation of the results, e.g. concerning the model uncertainties. For a realistic attribution of the model, we used existing petrophysical databases of the region and measured the magnetic susceptibility of more than 430 rock samples. As a result of the inversion, high-resolution voxel models of the density and susceptibility distribution were generated, allowing conclusions about the composition and structure of the crystalline crust, which leads to a reduction of uncertainties and risks associated with deep geothermal drillings in the northern Upper Rhine Graben. Furthermore, our model will serve as a basis for realistic simulations of heat transport processes in the fractured basement and a meaningful assessment of the deep geothermal potential in the future.

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