scholarly journals The interplay of Malm carbonate permeability, gravity-driven groundwater flow, and paleoclimate – implications for the geothermal field and potential in the Molasse Basin (southern Germany), a foreland-basin play

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Tom Vincent Schintgen ◽  
Inga Sigrun Moeck
Keyword(s):  
Groundwater Flow ◽  
Heat Transport ◽  
Foreland Basin ◽  
Geothermal Field ◽  
Molasse Basin ◽  
Carbonate Aquifer ◽  
Hydraulic Modelling ◽  
Southern Germany ◽  
Gravity Driven ◽  
The Impact

AbstractThe Molasse Basin in Southern Germany is part of the North Alpine Foreland Basin and hosts the largest accumulation of deep geothermal production fields in Central Europe. Despite the vast development of geothermal energy utilization projects especially in the Munich metropolitan region, the evolution of and control factors on the natural geothermal field, more specifically the time-varying recharge and discharge governing groundwater and heat flow, are still debated. Within the Upper Jurassic (Malm) carbonate aquifer as the main geothermal reservoir in the Molasse Basin, temperature anomalies such as the Wasserburg Trough anomaly to the east of Munich and their underlying fluid and heat transport processes are yet poorly understood. We delineate the two end members of thermal–hydraulic regimes in the Molasse Basin by calculating two contrasting permeability scenarios of the heterogeneously karstified Malm carbonate aquifer along a model section through the Wasserburg Trough anomaly by means of two-dimensional numerical thermal-hydraulic modelling. We test the sensitivity of the thermal-hydraulic regime with regard to paleoclimate by computing the two Malm permeability scenarios both with a constant surface temperature of 9 °C and with the impact of paleo-temperature changes during the last 130 ka including the Würm Glaciation. Accordingly, we consider the hydraulic and thermal effects of periglacial conditions like permafrost formation and the impact of the numerous glacial advances onto the Molasse Basin. Thermal-hydraulic modelling reveals the effect of recurrent glacial periods on the subsurface targets of geothermal interest, which is minor compared to the effect of permeability-related, continuous gravity-driven groundwater flow as a major heat transport mechanism.

The interplay of Malm carbonate permeability, gravity-driven groundwater flow, and paleoclimate – implications for the geothermal field and potential in the Molasse Basin (Southern Germany), a foreland-basin play

2021 ◽  
Author(s):  
Tom Vincent Schintgen ◽  
Inga Sigrun Moeck
Keyword(s):  
Groundwater Flow ◽  
Geothermal Energy ◽  
Foreland Basin ◽  
Geothermal Field ◽  
Molasse Basin ◽  
Carbonate Aquifer ◽  
Foreland Basins ◽  
Gravity Driven ◽  
The Impact ◽  
Subsurface Temperatures

Abstract The Molasse Basin in Southern Germany is part of the North Alpine Foreland Basin and hosts the largest accumulation of deep geothermal production fields in Central Europe. Despite the vast development of geothermal energy utilization projects especially in the Munich metropolitan region, the evolution of and control factors on the natural geothermal field are still debated. Especially seismic and deep well data from extensive oil and gas exploration in the Molasse Basin led to conceptual hydrogeological and thermal-hydraulic models. Corrected borehole-temperature data helped to constrain subsurface temperatures by geostatistical interpolation and facilitated the set-up of 3D temperature models. However, within the geothermally used Upper Jurassic (Malm) carbonate aquifer, temperature anomalies such as the Wasserburg Trough anomaly to the east of Munich and their underlying physical processes are yet poorly understood. From other foreland basins like the Alberta Basin in Western Canada, it is known that climate during the last ice age has a considerable effect even on subsurface temperatures up to two kilometres depth. Therefore, we study the impact of paleoclimatic changes on the Molasse Basin during the last 130 ka including the Würm glaciation. We consider the hydraulic and thermal effects of periglacial conditions like permafrost formation and the impact of the numerous glacial advances onto the Molasse Basin. The major difference between the thermal-hydraulic regime in the western and eastern parts of the Southern German Molasse Basin are delineated by calculating two contrasting permeability scenarios of the heterogeneously karstified Malm carbonate aquifer. Thermal-hydraulic modelling reveals the effect of recurrent glacial periods on the geothermally drillable subsurface, which is minor compared to the effect of permeability-related, continuous gravity-driven groundwater flow as a major heat transport mechanism. Practically, the results might help to reduce the exploration risk for geothermal energy projects in the Molasse Basin. More importantly, this study serves as a reference for the comparison and understanding of the interplay of high permeability aquifers, gravity-driven groundwater flow and paleoclimate in other orogenic foreland basins worldwide.

scholarly journals City-scale groundwater flow and heat transport modeling in the Milan Metropolitan Area

2020 ◽  
Author(s):  
Alberto Previati ◽  
Giovanni Battista Crosta ◽  
Jannis Epting
Keyword(s):  
Groundwater Flow ◽  
Heat Transport ◽  
Metropolitan Area ◽  
Thermal Regime ◽  
Rural Areas ◽  
Anthropogenic Heat ◽  
Heat Sources ◽  
Thermal Potential ◽  
The Impact ◽  
The City

<p>Aquifers beneath big cities are considered a very important resource from an energy and water supply point of view and are increasingly exploited by means of groundwater extraction wells as well as by shallow open- and closed-loop geothermal systems. Moreover, the shallow subsurface of densely populated cities is increasingly hosting underground infrastructures such as tunnels and building foundations. These activities lead to thermal pollution of the shallow urban underground. This phenomenon has already been documented (urban heat island effect) in many cities worldwide with higher ground/groundwater temperatures in the city centers with respect to surrounding rural areas. The local thermal impact of various underground activities has been studied with analytical and local-scale numerical modeling. However, the resulting groundwater thermal regime at the city-scale is yet mostly unexplored.</p><p>In this work the effects of anthropogenic heat sources and subsurface infrastructures in the Milan metropolitan area is presented. To this aim a groundwater head/temperature monitoring network was established in 2016. Groundwater temperatures in the city center are up to 3°C higher with respect to less urbanized areas. A correlation between the urban density and the groundwater thermal regime was observed. In order to evaluate the spatial variability of the groundwater temperatures, a detailed analysis based on a 3D FEM groundwater flow and heat transport numerical model was carried out by means of the commercial code FeFlow. First, the variability of hydraulic and thermal properties as from borehole logs was spatialized into the model by means of 3D geostatistical techniques to account for aquifer heterogeneities. Complex thermal boundary conditions were assigned to the model including the effects of different land cover/sealing materials, building foundations, tunnels, shallow geothermal wells and the canal network. The thermal transport model was calibrated against high-resolution time-lapse groundwater temperature profiles and continuous measurements at fixed depth.</p><p>The modeling of the current thermal regime of the shallow aquifers was essential to understand the hydrogeological and thermal processes that are relevant at the city scale. The numerical results are a valuable tool to assess the impact of specific heat sources as well as of surface/subsurface infrastructures on the overall thermal regime and to test the long-term thermal potential of ground/groundwater heat exchangers under possible urban development scenarios. Thereby, the proposed approach can support the sustainable development of subsurface infrastructures at the city-scale and the management and assessment of the thermal potential of low enthalpy geothermal resources.</p>

Influence of rotating magnetic field on Maxwell saturated ferrofluid flow over a heated stretching sheet with heat generation/absorption

2019 ◽  
Vol 20 (5) ◽  
pp. 502 ◽  
Author(s):  
Aaqib Majeed ◽  
Ahmed Zeeshan ◽  
Farzan Majeed Noori ◽  
Usman Masud
Keyword(s):  
Magnetic Field ◽  
Temperature Field ◽  
Velocity Field ◽  
Differential Equations ◽  
Heat Transport ◽  
Viscous Dissipation ◽  
Heat Generation ◽  
Fluid Motion ◽  
Numerical Procedure ◽  
The Impact

This article is focused on Maxwell ferromagnetic fluid and heat transport characteristics under the impact of magnetic field generated due to dipole field. The viscous dissipation and heat generation/absorption are also taken into account. Flow here is instigated by linearly stretchable surface, which is assumed to be permeable. Also description of magneto-thermo-mechanical (ferrohydrodynamic) interaction elaborates the fluid motion as compared to hydrodynamic case. Problem is modeled using continuity, momentum and heat transport equation. To implement the numerical procedure, firstly we transform the partial differential equations (PDEs) into ordinary differential equations (ODEs) by applying similarity approach, secondly resulting boundary value problem (BVP) is transformed into an initial value problem (IVP). Then resulting set of non-linear differentials equations is solved computationally with the aid of Runge–Kutta scheme with shooting algorithm using MATLAB. The flow situation is carried out by considering the influence of pertinent parameters namely ferro-hydrodynamic interaction parameter, Maxwell parameter, suction/injection and viscous dissipation on flow velocity field, temperature field, friction factor and heat transfer rate are deliberated via graphs. The present numerical values are associated with those available previously in the open literature for Newtonian fluid case (γ 1 = 0) to check the validity of the solution. It is inferred that interaction of magneto-thermo-mechanical is to slow down the fluid motion. We also witnessed that by considering the Maxwell and ferrohydrodynamic parameter there is decrement in velocity field whereas opposite behavior is noted for temperature field.

Groundwater Lowering for Construction of the Kilsby Tunnel – Geological and Geotechnical Interpretation

2021 ◽  
pp. 1-14
Author(s):  
Martin Preene ◽  
Mike Chrimes
Keyword(s):  
Groundwater Flow ◽  
Theoretical Understanding ◽  
Stress Theory ◽  
Glacial Origin ◽  
Buried Channel ◽  
Geological Information ◽  
Ground Conditions ◽  
Glacial Processes ◽  
The Impact ◽  
Groundwater Lowering

The Kilsby Tunnel, constructed in the 1830s, faced severe problems when a section of the tunnel, almost 400 m long, encountered unstable ‘quicksand’ conditions. The engineer for the project, Robert Stephenson, developed an extensive groundwater lowering scheme, unique for the time, using steam engines pumping from multiple shafts, to overcome the quicksand. Modern geological information indicates most of the tunnel was in Middle Lias bedrock, but the ‘quicksand’ section passed through a buried channel of water-bearing sand of glacial origin. In the early 19th century the impact of glacial processes on British geology was not widely accepted and, based on contemporary geological knowledge, Stephenson’s problems appear to be genuine unforeseen ground conditions, not predicted by his experienced advisers. It seems just random chance that trial borings missed the buried channel of sand. The work at Kilsby was two decades before Darcy’s law established the theoretical understanding for groundwater flow, and 90 years before Terzaghi’s effective stress theory described how reducing pore water pressures changed ‘quicksand’ into a stable and workable material. Despite the lack of existing theories, Stephenson used careful observations and interpretation of groundwater flow in the ‘quicksand’ to navigate the tunnel project to a successful conclusion.

scholarly journals Groundwater flow and heat transport for systems undergoing freeze-thaw: Intercomparison of numerical simulators for 2D test cases

2018 ◽  
Vol 114 ◽  
pp. 196-218 ◽  
Author(s):  
Christophe Grenier ◽  
Hauke Anbergen ◽  
Victor Bense ◽  
Quentin Chanzy ◽  
Ethan Coon ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Heat Transport ◽  
Test Cases ◽  
Freeze Thaw

scholarly journals Numerical Modeling of the Interference of Thermally Unbalanced Aquifer Thermal Energy Storage Systems in Brussels (Belgium)

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6241
Author(s):  
Manon Bulté ◽  
Thierry Duren ◽  
Olivier Bouhon ◽  
Estelle Petitclerc ◽  
Mathieu Agniel ◽  
...  
Keyword(s):  
Energy Storage ◽  
Groundwater Flow ◽  
Heat Transport ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Cold Water ◽  
Cooling System ◽  
Joint Operation ◽  
Groundwater Temperature ◽  
Aquifer Thermal Energy Storage

A numerical model was built using FEFLOW® to simulate groundwater flow and heat transport in a confined aquifer in Brussels where two Aquifer Thermal Energy Storage (ATES) systems were installed. These systems are operating in adjacent buildings and exploit the same aquifer made up of mixed sandy and silty sublayers. The model was calibrated for groundwater flow and partially for heat transport. Several scenarios were considered to determine if the two ATES systems were interfering. The results showed that a significant imbalance between the injection of warm and cold water in the first installed ATES system led to the occurrence of a heat plume spreading more and more over the years. This plume eventually reached the cold wells of the same installation. The temperature, therefore, increased in warm and cold wells and the efficiency of the building’s cooling system decreased. When the second ATES system began to be operational, the simulated results showed that, even if the heat plumes of the two systems had come into contact, the influence of the second system on the first one was negligible during the first two years of joint operation. For a longer modeled period, simulated results pointed out that the joint operation of the two ATES systems was not adapted to balance, in the long term, the quantity of warm and cold water injected in the aquifer. The groundwater temperature would rise inexorably in the warm and cold wells of both systems. The heat plumes would spread more and more over the years at the expense of the efficiency of both systems, especially concerning building’s cooling with stored cold groundwater.

scholarly journals Estimating uncertainties in hydraulicallymodelled rating curves for discharge time series assessment

2018 ◽  
Vol 40 ◽  
pp. 06013
Author(s):  
Valentin Mansanarez ◽  
Ida K. Westerberg ◽  
Steve W. Lyon ◽  
Norris Lam
Keyword(s):  
Time Series ◽  
Hydraulic Model ◽  
Observation Data ◽  
Rating Curve ◽  
Hydraulic Modelling ◽  
Discharge Time ◽  
High Flows ◽  
Rating Curves ◽  
Hydrometric Station ◽  
The Impact

Establishing a reliable stage-discharge (SD) rating curve for calculating discharge at a hydrological gauging station normally takes years of data collection. Estimation of high flows is particularly difficult as they occur rarely and are often difficult to gauge in practice. At a minimum, hydraulicallymodelled rating curves could be derived with as few as two concurrent SD and water-surface slope measurements at different flow conditions. This means that a reliable rating curve can, potentially, be developed much faster via hydraulic modelling than using a traditional rating curve approach based on numerous stage-discharge gaugings. In this study, we use an uncertainty framework based on Bayesian inference and hydraulic modelling for developing SD rating curves and estimating their uncertainties. The framework incorporates information from both the hydraulic configuration (bed slope, roughness, vegetation) using hydraulic modelling and the information available in the SD observation data (gaugings). Discharge time series are estimated by propagating stage records through the posterior rating curve results. Here we apply this novel framework to a Swedish hydrometric station, accounting for uncertainties in the gaugings and the parameters of the hydraulic model. The aim of this study was to assess the impact of using only three gaugings for calibrating the hydraulic model on resultant uncertainty estimations within our framework. The results were compared to prior knowledge, discharge measurements and official discharge estimations and showed the potential of hydraulically-modelled rating curves for assessing uncertainty at high and medium flows, while uncertainty at low flows remained high. Uncertainty results estimated using only three gaugings for the studied site were smaller than ±15% for medium and high flows and reduced the prior uncertainty by a factor of ten on average and were estimated with only 3 gaugings.

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