The origin of deep geothermal anomalies in the German Molasse Basin: results from 3D numerical models of coupled fluid flow and heat transport

Przybycin, Anna M.; Scheck‐Wenderoth, Magdalena; Schneider, Michael

doi:10.1186/s40517-016-0059-3

Cited by 33 publications

(25 citation statements)

References 27 publications

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“…Except for the shale-rich stratigraphic units (Chattian, Rupelian, Lattorf/Sannoisian and Upper Cretaceous), porosity and permeability (Table 3) have been modeled using Athy's depth-porosity relationship (Athy 1930) and a three-point porosity-permeability relationship, respectively, with parameters for both porosity and permeability models provided by Hantschel and Kauerauf (2009). Thereby, the Neogene (Miocene and younger) sections have been modeled as permeable siliciclastic sands, while the Lower Cretaceous and Upper Jurassic have been modeled as a nearly uncompressible limestone to mimic the high permeability present in these carbonates even at depths > 4000 m (Przybycin et al 2017). The Eocene Lithothamnium Limestone has been modeled with chalk properties to represent a fast compacting limestone.…”

Section: Lithological and Petrophysical Constraintsmentioning

confidence: 99%

RETRACTED ARTICLE: Predictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well

et al. 2019

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For the first time, drilling-and velocity-based well analysis and 3D basin modeling were combined to test the predictability and controlling factors of overpressure in the North Alpine Foreland Basin in SE Germany. More specifically, the techniques were tested in the sub-regional context of the deep geothermal well Geretsried GEN-1 (TVD = 4852 m), located in the south of Munich. A 3D basin model based on a total of 20 wells was calibrated to the pressure distribution of four petroleum wells and tested against the Geretsried GEN-1 well. The results demonstrate that overpressure in the North Alpine Foreland Basin SE Germany can be predicted from a simple 3D basin model calibrated to a minimum number of wells. Thereby, disequilibrium compaction likely acts as the main overpressure mechanism in the study area, underpinned by significantly higher sedimentation rates at overpressured locations. 3D basin modeling also confirms the role of Upper Cretaceous shales, which, if present, serve as an important pressure barrier between the under-to normally pressured Jurassic and overpressured Cenozoic basin fill. In addition, overpressure magnitudes of the Chattian might be higher than previously expected. The results of this study have great impact on future drilling campaigns in the North Alpine Foreland Basin in SE Germany. Minimized non-productive time and drilling cost, improved well planning and increased safety are amongst the most important benefits of accurate pore pressure and overpressure prediction. The newly derived insights on the mechanisms of overpressure will greatly influence future geomechanical and tectonic studies, since pore pressure drives rock strength and principle stress magnitudes. Finally, the study is a great example for the importance of an interdisciplinary approach and the incorporation of geological conditions, when investigating drilling-related problems. Open Access© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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Section: Lithological and Petrophysical Constraintsmentioning

confidence: 99%

RETRACTED ARTICLE: Predictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well

et al. 2019

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“…1) and reaches from the ground surface to a depth of 11 km below sea level. The lithology is based on the geological model of Przybycin et al (2017Przybycin et al ( , 2014 that uses freely available lithological information from boreholes and seismic lines to describe the subsurface geometry in the Molasse Basin. Furthermore, the geometry has been constrained by 3D gravity modelling (Przybycin et al 2017).…”

Section: Model Area and Basic Assumptionsmentioning

confidence: 99%

“…The lithology is based on the geological model of Przybycin et al (2017Przybycin et al ( , 2014 that uses freely available lithological information from boreholes and seismic lines to describe the subsurface geometry in the Molasse Basin. Furthermore, the geometry has been constrained by 3D gravity modelling (Przybycin et al 2017). A total of 13 geologic units are distinguished (Table 1) with a focus on the six thin southward dipping Jurassic units of Malm alpha to Malm zeta, which are target formations for geothermal applications (Lemcke 1988;Bachmann et al 1987;Fritzer et al 2012).…”

Section: Model Area and Basic Assumptionsmentioning

confidence: 99%

“…Thus, the geologic model is discretised with 2.95 × 10 6 8-node hexahedron elements. Each element has a lateral extend of 1500 × 1500 m 2 which approximately corresponds to the resolution of the geologic model (Przybycin et al 2017(Przybycin et al , 2014. Despite this comparably The resulting high vertical resolution allows resolving the mechanical differences between the six thin Malm units.…”

Section: Model Area and Basic Assumptionsmentioning

confidence: 99%

“…Depths (b.s.l.) of top Malm delta is indicated by coloured isolines(Przybycin et al 2017). Model area is indicated by the rectangular box.…”

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The 3D stress state from geomechanical–numerical modelling and its uncertainties: a case study in the Bavarian Molasse Basin

Ziegler

Heidbach

2020

Geotherm Energy

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Knowledge of the undisturbed stress state is a key parameter for borehole stability, productivity and induced seismicity hazard assessment. Due to the sparse and incomplete availability of data records, 3D geomechanical–numerical modelling is applied to estimate the stress state in a volume. To assess the quality of the model results, the model uncertainties have to be quantified. We present an approach that provides the uncertainties of the six independent stress tensor components at each location in the model volume by an average value and its standard deviation. We explore the uncertainties introduced to the model results with respect to the stress magnitude data used for model calibration. We test our approach on a model of the Bavarian Molasse Basin which includes the area around Munich with many geothermal projects. In the test area, we find large uncertainties in the modelled magnitude of the maximum horizontal stress ($$\text{S}_\text {Hmax}$$SHmax) in the order of 15–30%. The uncertainties in the magnitude of the minimum horizontal stress ($$\text{S}_\text {hmin}$$Shmin) are smaller between 5 and 20%. In connection with an adequate failure criterion, we compare our model results to the seismological observations at two neighbouring geothermal projects. Whilst Aschheim/Feldkirchen/Kirchheim remained seismically quiet, induced seismicity was recorded in Poing. Our modelled undisturbed stress state was confirmed by these observations by showing in average a stable stress state in Aschheim/Feldkirchen/Kirchheim and a critical stress state in Poing. If the uncertainties in terms of two standard deviations are considered, this does not change. This demonstrates the increase in model significance when uncertainties are available.

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In Situ Stress State of the Ruhr Region (Germany) and Its Implications for Permeability Anisotropy

et al. 2021

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In this study, we carried out reactivation potential analysis of discontinuities revealed from four exploration boreholes penetrating heavily faulted and folded Upper Carboniferous rock strata of the Ruhr region. We performed this study based on the notion that slip is controlled by the ratio of shear to effective normal stresses acting on a pre-existing plane of weakness in the prevailing stress field configuration. The results of this analysis were supported by indicators of localized fluid flow, both on micro- and macro-scales, which confirm relationship between secondary permeability and in situ stress state in the Ruhr region. Findings from this study, in conjunction with results of destructive laboratory testing, indicate that the steep NW–SE- and NNE–SSW-striking planar discontinuities are likely to be either close to the critical state or critically stressed in the in situ stress configuration in the Ruhr region. These planar structures, as evidenced by indicators of localized permeability, are the main fluid pathways in the studied region. The NE–SW-striking discontinuities, on the other hand, are most likely to be closed and hydraulically inactive in the prevailing stress state. Based on results gained from this study, implications for utilization of deep geothermal energy in the region were discussed.

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The origin of deep geothermal anomalies in the German Molasse Basin: results from 3D numerical models of coupled fluid flow and heat transport

Cited by 33 publications

References 27 publications

RETRACTED ARTICLE: Predictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well

RETRACTED ARTICLE: Predictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well

The 3D stress state from geomechanical–numerical modelling and its uncertainties: a case study in the Bavarian Molasse Basin

In Situ Stress State of the Ruhr Region (Germany) and Its Implications for Permeability Anisotropy

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