Geological Processes to Consider for Modeling the Distribution of Hydrogeological Properties in Fractured Crystalline Rocks on a Site Scale

2020 ◽  
Author(s):  
Peter Achtziger-Zupancic ◽  
Simon Loew
Keyword(s):  
Crystalline Rocks ◽  
Influential Factors ◽  
Contact Metamorphism ◽  
Main Process ◽  
Depth Range ◽  
Geological Processes ◽  
Wide Range ◽  
Fracture Closure ◽  
Fractured Crystalline Rocks ◽  
Hydrogeological Properties

<p>Reliable predictions of the distribution of permeabilities on site scale are economically relevant in a wide range of geoscientific disciplines. Not only are predictions important for modeling hydrogeological conditions at site scale but also for using the underground safely and sustainably.</p><p>Scale dependent, different geological processes are influencing the distribution of hydrogeological properties. A dataset of about 5000 inflows from individual transmissive fractures draining to about 660 km of drifts and 57 km of boreholes has been compiled into depths of 2000 mbgs of the Variscan age German Ore Mountains (Erzgebirge/Krušné hory). Fracture closure with increasing depth is a main process controlling the distribution of transmissivities. Additionally, orientation, age and mode of fault zones exert a major control on the local distribution of inflows. These factors are locally overprinted by with the presence of contact metamorphic aureoles around Variscan granitic intrusions as seen from transmissivity reversals with depth. However, as seen from a decreasing trend of mean log hydraulic conductivity and permeability, the contact metamorphism exerts minor control on the rock mass hydrology with depth than the decreasing secondary porosity provided by fractures.</p><p>These findings are in accordance with results deduced from a worldwide permeability compilation of about 30000 single in-situ permeability measurements to depths of 2000 mbgs. Geological influences on the distribution have been analyzed on permeability-depth relationships using log-log regressions. Depth is generally the most important geological factor, resulting in a permeability decrease of three to four orders of magnitude in the investigated depth range. Beside depth, most influential factors are the long-term tectono-geological history described by geological province which locally is overprinted by current seismotectonic activity as determined by peak ground acceleration. Although petrography might be of local importance, only a low impact has been observed for the global dataset, besides lithologies allowing for karstification.</p><p>In summary, the multi-variate analysis of the datasets has improved our generic understanding of the distribution of hydrogeological properties and provides a basis to model hydrogeological processes in fractured crystalline rocks.</p>

Environmental impacts of tunnels in fractured crystalline rocks of the Central Alps

2007 ◽  
pp. 507-526
Author(s):  
Keith Evans ◽  
Christian Zangerl ◽  
Volker Luetzenkirchen ◽  
Simon Loew ◽  
Erik Eberhardt ◽  
...  
Keyword(s):  
Environmental Impacts ◽  
Crystalline Rocks ◽  
Central Alps ◽  
Fractured Crystalline Rocks

scholarly journals The Relationship between Fluid Flow, Structures, and Depositional Architecture in Sedimentary Rocks: An Example-Based Overview

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-19 ◽  
Author(s):  
Vilde Dimmen ◽  
Atle Rotevatn ◽  
Casey W. Nixon
Keyword(s):  
Fluid Flow ◽  
Sedimentary Rocks ◽  
Structure Type ◽  
Mineral Dissolution ◽  
Rock Properties ◽  
Hydrocarbon Migration ◽  
Geological Processes ◽  
Wide Range ◽  
Depositional Architecture ◽  
The Relationship

Fluid flow in the subsurface is fundamental in a variety of geological processes including volcanism, metamorphism, and mineral dissolution and precipitation. It is also of economic and societal significance given its relevance, for example, within groundwater and contaminant transport, hydrocarbon migration, and precipitation of ore-forming minerals. In this example-based overview, we use the distribution of iron oxide precipitates as a proxy for palaeofluid flow to investigate the relationship between fluid flow, geological structures, and depositional architecture in sedimentary rocks. We analyse and discuss a number of outcrop examples from sandstones and carbonate rocks in New Zealand, Malta, and Utah (USA), showing controls on fluid flow ranging from simple geological heterogeneities to more complex networks of structures. Based on our observations and review of a wide range of the published literature, we conclude that flow within structures and networks is primarily controlled by structure type (e.g., joint and deformation band), geometry (e.g., length and orientation), connectivity (i.e., number of connections in a network), kinematics (e.g., dilation and compaction), and interactions (e.g., relays and intersections) within the network. Additionally, host rock properties and depositional architecture represent important controls on flow and may interfere to create hybrid networks, which are networks of combined structural and stratal conduits for flow.

scholarly journals Experimental investigation of the parameters of water solution purposes by ceramic, coal filters and reverse-osmotic module

2019 ◽  
pp. 30-33
Author(s):  
S.V. Gulienko
Keyword(s):  
Reverse Osmosis ◽  
Water Solution ◽  
Ceramic Filter ◽  
Main Process ◽  
Working Pressure ◽  
Ceramic Filters ◽  
Quality Of Water ◽  
Urgent Task ◽  
Wide Range ◽  
Series Of Experiments

The urgent task is to research in detail the possibilities of operation of the reverse osmosis membrane in the conditions of changing various parameters, which include, first of all, the working pressure, the initial concentration of the cleaning solutions, as well as the working conditions and the complete set of cleaning stands with auxiliary filters: mechanical, ceramic and carbon, which improves the quality of water and increases the life of high-value reverse osmosis modules. Particular attention was paid in this series of experiments to the role of ceramic filters, since in the previous series of experiments the concentration of the solution did not change both after mechanical and after carbon filters. Therefore, it was decided to modernize the stand and use a ceramic filter in the flow chart. In this work the detailed scheme of bench-scale setup with using of ceramic and carbon filters and also reverse-osmosis module is represented. The experimental reseaches of purification of NaCl water solutions were carried out in wide range of concentrations (0,2∙10-3…6,5 g/l) and working pressures (0,2…0,65 MPa). The comparative characteristics of main process parameters with and without ceramic filter are represented. The experiments were carried out on a laboratory stand for complex purification of aqueous solutions by microfiltration, adsorption and reverse osmosis using the following process steps carried out in the respective apparatus.

Reflection seismic imaging of buried shallow salt structures – examples from ongoing case studies in Northern Germany

2021 ◽  
Author(s):  
Ulrich Polom ◽  
Rebekka Mecking ◽  
Phillip Leineweber ◽  
Andreas Omlin
Keyword(s):  
High Resolution ◽  
Water Resources ◽  
Industrial Development ◽  
Geophysical Methods ◽  
Hydrocarbon Exploration ◽  
P Wave ◽  
Depth Range ◽  
Reflection Seismic ◽  
Wide Range ◽  
Cap Rock

<p>In the North German Basin salt tectonics generated a wide range of evaporite structures since the Upper Triassic, resulting in e.g. extended salt walls, salt diapirs, and salt pillows in the depth range up to 8 km. Due to their trap and seal properties these structures were in the focus of hydrocarbon exploration over many decades, leading to an excellent mapping of their geometries below 300 m in depth. During salt rise Rotliegend formations were partly involved as a constituent. Some structures penetrated the salt table, some also the former surface. Dissolution (subrosion) and erosion of the salt cap rock by meteoric water took place, combined with several glacial and intraglacial overprints. Finally the salt structures were covered by pleistocene and holocene sediments. This situation partly resulted in proneness for ongoing karstification of the salt cap rock, leading to e.g. local subsidence and sinkhole occurrence at the surface. The geometry, structure and internal lithology of these shallow salt cap rocks are widely unknown. Expanding urban and industrial development, water resources management and increasing climate change effects enhance the demands for shallow mapping and characterization of these structures regarding save building grounds and sustainable water resources.</p><p>Results of shallow drilling investigations of the salt cap rock and the overburden show unexpectedly heterogenous subsurface conditions, yielding to limited success towards mapping and characterization. Thus, shallow high-resolution geophysical methods are in demand to close the gaps with preferred focus of applicability in urban and industrial environments. Method evaluations starting in 2010 geared towards shallow high-resolution reflection seismic to meet the requirements of both depth penetration and structure resolution. Since 2017 a combination of S-wave and P-wave seismic methods including depth calibrations by Vertical Seismic Profiling (VSP) enabled 2.5D subsurface imaging starting few meters below the surface up to several hundred meters depth in 0.5-5 m resolution range, respectively. The resulting profiles image strong variations along the boundaries and on top of the salt cap rock. Beside improved mapping capabilities, aim of research is the development of characteristic data features to differentiate save and non-save areas.</p>

Drawing schematic diagrams

2019 ◽  
pp. 254-266
Author(s):  
Matthew J. Genge
Keyword(s):  
Earth Science ◽  
Worked Examples ◽  
Geological Processes ◽  
Wide Range ◽  
Field Notes ◽  
Process Diagrams ◽  
Schematic Diagrams

Schematic diagrams are invaluable in Earth Science in the communication of concepts in both publications and teaching. These diagrams can also be used during fieldwork to help develop interpretations of structures, palaeoenvironments, and geological processes. This chapter describes methods used to create block diagrams of structures and landscapes, surface diagrams of folds and faults, and process diagrams used to summarize interpretations of a wide range of processes. Schematic diagrams can and should be included in field notes. Process diagrams represent a cartoon of interpretative thoughts. Four worked examples of schematic diagrams are provided to illustrate their uses and construction.

scholarly journals Estimation of Transmissivity and Permeability in Swedish Bedrock

1977 ◽  
Vol 8 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Leif Carlsson ◽  
Anders Carlstedt
Keyword(s):  
Statistical Analysis ◽  
Test Data ◽  
Hydraulic Properties ◽  
Pumping Test ◽  
Crystalline Rocks ◽  
Wide Range ◽  
Well Loss

Statistical analysis of pumping-test data from wells have been used to calculate average values of transmissivity and permeability in different Swedish rocks. The influence of the well-loss on the calculations is discussed. The highest values of transmissivity and permeability of the investigated rocks are found in the sandstones of Algonkian and Cambrian age. The Archean crystalline rocks show a wide range of results, and of the investigated rocks the gneisses seem to be more permeable than the granites. However, the degree of tectonization affects the hydraulic properties of the rocks considerably.

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