S-wave Seismic Experiments for Geothermal Exploration of the Upper Jurassic Carbonate Platform in the Bavarian Molasse Basin

2017 ◽  
Author(s):  
B. Wawerzinek ◽  
H. Buness ◽  
R. Thomas
Keyword(s):  
Carbonate Platform ◽  
Upper Jurassic ◽  
Molasse Basin ◽  
S Wave ◽  
Geothermal Exploration

scholarly journals S-wave experiments for the exploration of a deep geothermal carbonate reservoir in the German Molasse Basin

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Britta Wawerzinek ◽  
Hermann Buness ◽  
Hartwig von Hartmann ◽  
David C. Tanner
Keyword(s):  
Upper Jurassic ◽  
Carbonate Reservoir ◽  
P Wave ◽  
Seismic Survey ◽  
Seismic Exploration ◽  
Molasse Basin ◽  
S Wave ◽  
Induced Earthquakes ◽  
Conversion Point ◽  
Facies Classification

AbstractThere are many successful geothermal projects that exploit the Upper Jurassic aquifer at 2–3 km depth in the German Molasse Basin. However, up to now, only P-wave seismic exploration has been carried out. In an experiment in the Greater Munich area, we recorded S-waves that were generated by the conventional P-wave seismic survey, using 3C receivers. From this, we built a 3D volume of P- to S-converted (PS) waves using the asymptotic conversion point approach. By combining the P-volume and the resulting PS-seismic volume, we were able to derive the spatial distribution of the vp/vs ratio of both the Molasse overburden and the Upper Jurassic reservoir. We found that the vp/vs ratios for the Molasse units range from 2.0 to 2.3 with a median of 2.15, which is much higher than previously assumed. This raises the depth of hypocenters of induced earthquakes in surrounding geothermal wells. The vp/vs ratios found in the Upper Jurassic vary laterally between 1.5 and 2.2. Since no boreholes are available for verification, we test our results against an independently derived facies classification of the conventional 3D seismic volume and found it correlates well. Furthermore, we see that low vp/vs ratios correlate with high vp and vs velocities. We interpret the latter as dolomitized rocks, which are connected with enhanced permeability in the reservoir. We conclude that 3C registration of conventional P-wave surveys is worthwhile.

scholarly journals Multiphase, decoupled faulting in the southern German Molasse Basin – evidence from 3-D seismic data

Solid Earth ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 2097-2117
Author(s):  
Vladimir Shipilin ◽  
David C. Tanner ◽  
Hartwig von Hartmann ◽  
Inga Moeck
Keyword(s):  
Carbonate Platform ◽  
Three Dimensional ◽  
Upper Jurassic ◽  
Thrust Fault ◽  
Normal Faults ◽  
Molasse Basin ◽  
Maximum Displacement ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Structural Style

Abstract. We use three-dimensional seismic reflection data from the southern German Molasse Basin to investigate the structural style and evolution of a geometrically decoupled fault network in close proximity to the Alpine deformation front. We recognise two fault arrays that are vertically separated by a clay-rich layer – lower normal faults and upper normal and reverse faults. A frontal thrust fault partially overprints the upper fault array. Analysis of seismic stratigraphy, syn-kinematic strata, throw distribution, and spatial relationships between faults suggest a multiphase fault evolution: (1) initiation of the lower normal faults in the Upper Jurassic carbonate platform during the early Oligocene, (2) development of the upper normal faults in the Cenozoic sediments during the late Oligocene, and (3) reverse reactivation of the upper normal faults and thrusting during the mid-Miocene. These distinct phases document the evolution of the stress field as the Alpine orogen propagated across the foreland. We postulate that interplay between the horizontal compression and vertical stresses due to the syn-sedimentary loading resulted in the intermittent normal faulting. The vertical stress gradients within the flexed foredeep defined the independent development of the upper faults above the lower faults, whereas mechanical behaviour of the clay-rich layer precluded the subsequent linkage of the fault arrays. The thrust fault must have been facilitated by the reverse reactivation of the upper normal faults, as its maximum displacement and extent correlate with the occurrence of these faults. We conclude that the evolving tectonic stresses were the primary mechanism of fault activation, whereas the mechanical stratigraphy and pre-existing structures locally governed the structural style.

scholarly journals The stones of the Sanctuary of Delphi – Northern shore of the Corinth Gulf – Greece

2020 ◽  
Vol 191 ◽  
pp. 11
Author(s):  
Marilou de Vals ◽  
Renaldo Gastineau ◽  
Amélie Perrier ◽  
Romain Rubi ◽  
Isabelle Moretti
Keyword(s):  
Carbonate Platform ◽  
Hanging Wall ◽  
Normal Fault ◽  
Archaeological Site ◽  
Upper Jurassic ◽  
Coarse Grained ◽  
Corinth Gulf ◽  
Gulf Of Corinth ◽  
Tethys Ocean ◽  
Open Question

The choice of stones by the ancient Greeks to build edifices remains an open question. If the use of local materials seems generalized, allochthonous stones are usually also present but lead to obvious extra costs. The current work aims to have an exhaustive view of the origins of the stones used in the Sanctuary of Delphi. Located on the Parnassus zone, on the hanging wall of a large normal fault related to the Corinth Rift, this Apollo Sanctuary is mainly built of limestones, breccia, marbles, as well as more recent poorly consolidated sediments generally called pôros in the literature. To overpass this global view, the different lithologies employed in the archaeological site have been identified, as well as the local quarries, in order to find their origins. The different limestones are autochthons and come from the Upper Jurassic – Cretaceous carbonate platform of the Tethys Ocean involved in the Hellenides orogen. Those limestones of the Parnassus Massif constitute the majority of the rock volume in the site; a specific facies of Maastrichtian limestone called “Profitis Ilias limestone” has been used for the more prestigious edifices such as the Apollo Temple. The corresponding ancient quarry is located few kilometers west of the sanctuary. Then, slope breccia has been largely used in the sanctuary: it crops out in and around the site and is laying on top of the carbonates. Finally, the pôros appear to be very variable and seven different facies have been documented, including travertine, oolitic grainstone, marine carbonates and coarse-grained sandstones. All these recent facies exist in the south-east shore of the Gulf of Corinth, although – except for the grainstone – the quarries are not yet known.

scholarly journals Temporal evolution of fault systems in the Upper Jurassic of the Central German Molasse Basin: case study Unterhaching

2017 ◽  
Vol 107 (2) ◽  
pp. 635-653 ◽  
Author(s):  
Ingmar Budach ◽  
Inga Moeck ◽  
Ewald Lüschen ◽  
Markus Wolfgramm
Keyword(s):  
Temporal Evolution ◽  
Upper Jurassic ◽  
Molasse Basin ◽  
Fault Systems

Jurassic raft tectonics in the northeastern Gulf of Mexico

2014 ◽  
Vol 2 (4) ◽  
pp. SM39-SM55 ◽  
Author(s):  
Robin S. Pilcher ◽  
Ryan T. Murphy ◽  
Jessica McDonough Ciosek
Keyword(s):  
Gulf Of Mexico ◽  
Carbonate Platform ◽  
Upper Jurassic ◽  
Petroleum Exploration ◽  
Original Position ◽  
Smackover Formation ◽  
The North ◽  
Structural Style ◽  
Cotton Valley ◽  
Northeastern Gulf Of Mexico

The northeastern Gulf of Mexico is dominated by the 900–1800-m Florida Escarpment, which forms the bathymetric expression of the Cretaceous carbonate shelf edge. Outboard of the escarpment lies a region of salt-detached raft blocks, which are closely analogous to type examples in the Kwanza Basin, Angola, in terms of structural style, scale, and amount of extension. We undertook the first detailed structural interpretation of an emerging petroleum exploration province. The rafts detached and translated basinward by gravity gliding on the autochthonous Louann salt in the late Jurassic to early Cretaceous. The Upper Jurassic source rock (lime mudstones) of the Smackover Formation and eolian sandstone reservoir intervals of the Norphlet Formation are structurally segmented and entirely contained within the raft blocks. The rafts are separated by salt ridges and/or extensional fault gaps containing expanded uppermost Jurassic and lower Cretaceous strata of the Cotton Valley Group. The main episode of rafting occurred after deposition of the Smackover and Haynesville Formations and broke the Jurassic carbonate platform into raft blocks 2–40 km in length, which were then translated 25–40 km basinward from their original position. Map-view restoration of the raft blocks suggested a minimum extension of 100%, with basinward transport directions indicating a radial divergence of rafts. In the north of the study area, the transport direction was westerly, whereas in the south, translation was southerly. This pattern, which mimics the Florida Escarpment, suggested that the morphology of the Jurassic slope controlled the style of gravitational tectonics and the location of subsequent Cretaceous carbonate buildups. As with other linked systems on mobile substrates, the observed extension and translation must be balanced by downdip contraction. In the case of the northeastern Gulf of Mexico, the contraction is largely cryptic, being accommodated by salt evacuation, compression of salt walls/stocks, and possibly open-toed canopy advance.

scholarly journals Reservoir characterization of the Upper Jurassic geothermal target formations (Molasse Basin, Germany): role of thermofacies as exploration tool

2015 ◽  
Vol 3 (1) ◽  
pp. 41-49 ◽  
Author(s):  
S. Homuth ◽  
A. E. Götz ◽  
I. Sass
Keyword(s):  
Thermal Conductivity ◽  
Reservoir Characterization ◽  
Upper Jurassic ◽  
Dominant Factor ◽  
Physical Parameters ◽  
Minor Effect ◽  
Molasse Basin ◽  
Reservoir Property ◽  
Triaxial Cell ◽  
Reservoir Conditions

<p><strong>Abstract.</strong> The Upper Jurassic carbonates of the southern German Molasse Basin are the target of numerous geothermal combined heat and power production projects since the year 2000. A production-orientated reservoir characterization is therefore of high economic interest. Outcrop analogue studies enable reservoir property prediction by determination and correlation of lithofacies-related thermo- and petrophysical parameters. A thermofacies classification of the carbonate formations serves to identify heterogeneities and production zones. The hydraulic conductivity is mainly controlled by tectonic structures and karstification, whilst the type and grade of karstification is facies related. The rock permeability has only a minor effect on the reservoir's sustainability. Physical parameters determined on oven-dried samples have to be corrected, applying reservoir transfer models to water-saturated reservoir conditions. To validate these calculated parameters, a Thermo-Triaxial-Cell simulating the temperature and pressure conditions of the reservoir is used and calorimetric and thermal conductivity measurements under elevated temperature conditions are performed. Additionally, core and cutting material from a 1600 m deep research drilling and a 4850 m (total vertical depth, measured depth: 6020 m) deep well is used to validate the reservoir property predictions. Under reservoir conditions a decrease in permeability of 2–3 magnitudes is observed due to the thermal expansion of the rock matrix. For tight carbonates the matrix permeability is temperature-controlled; the thermophysical matrix parameters are density-controlled. Density increases typically with depth and especially with higher dolomite content. Therefore, thermal conductivity increases; however the dominant factor temperature also decreases the thermal conductivity. Specific heat capacity typically increases with increasing depth and temperature. The lithofacies-related characterization and prediction of reservoir properties based on outcrop and drilling data demonstrates that this approach is a powerful tool for exploration and operation of geothermal reservoirs.</p>

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