ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Permeability and stress in crystalline rocks (1996)
    In:  Terra Nova, Warszawa, Bundesanstalt für Geowissenschaften und Rohstoffe, vol. 8, no. 3, pp. 223-235, pp. 2121
    Details
    Publication Date: 1996
    Keywords: Stress ; Physical properties of rocks
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    BIBLIOGRAPHY SEISMOLOGY
  • 2
    facet.materialart.
    Unknown
    Scaling of fracture systems in geological media (2001)
    In:  Rev. Geophys., Luxembourg, Conseil de l'Europe, vol. 39, no. 3, pp. 347-383, pp. L15S17, (ISBN: 0-12-018847-3)
    Details
    Publication Date: 2001
    Keywords: Scaling ; cracks and fractures (.NE. fracturing) ; lognormal ; gamma ; power ; law ; FractureT ; Fault zone ; SAF ; Physical properties of rocks ; 3250 ; Mathematical ; geophysics ; (new ; field) ; Fractals ; and ; multifractals ; 5104 ; Physical ; properties ; of ; rocks ; Fracture ; and ; flow ; 8010 ; Structural ; geology ; 8165 ; Fractures ; and ; faults
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    BIBLIOGRAPHY SEISMOLOGY
  • 3
    Electronic Resource
    Electronic Resource
    Natural fracture profiles, fractal dimension and joint roughness coefficients (1994)
    Springer
    Rock mechanics and rock engineering 27 (1994), S. 135-153 
    Details
    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: Summary Thirteen natural rock profiles (Barton and Choubey, 1977) are analyzed for their fractal properties. Most of the profiles were found to approximate fractal curves but some also showed features of specific wavelengths and amplitudes superimposed on fractal characteristics. The profiles showed fractal dimensions from 1.1 to 1.5 covering a range of selfsimilar and self-affine curves. The analysis results suggest a negative correlation between fractal dimension,D, and amplitude,A. Joint roughness coefficients (JRC) show a positive correlation with amplitude,A, and a negative correlation with fractal dimension,D. A numerical model of fracture closure is used to investigate the effects of different profile characteristics (D, A and sample size) on the nature of dilation and contact area, using the natural profiles and synthetic fractional Brownian motion profiles. Smooth profiles (low JRC, highD, lowA) display many small contact regions whereas rough fractures (high JRC, lowD, highA) display few large contact areas. The agreement with published experimental data supports the suggested correlations between JRC and the fractal parameters,A andD. It is suggested that observed scale effects in JRC and joint dilation can be explained by small differential strain discontinuities across fractures, which originate at the time of fracture formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01020307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    facet.materialart.
    Unknown
    Properties of fault damage zones in siliclastic rocks: a modelling approach (2007)
    In:  Geological Society Special Publication 249: 43-59.
    Details
    Publication Date: 2007-10-08
    Description: Major faults are surrounded by damage zones of minor faults that, in siliclastic rocks, can form barriers to flow in their own right. Reservoir flow simulation -- now a routine part of reservoir management -- requires equivalent hydraulic parameters on the scale of the whole fault, while reservoir geological models, from which flow simulator grids are generated, require information on the 3D characteristics of fault populations. Here, a stochastic model of fault damage zone architecture is generated and used to explore the impact of damage zone architecture on extrapolation from 1D (fault throw) and 2D (fault length) to 3D fault population characteristics. Sampling of the simulated damage zone models shows that clustering of faults causes deviations from simple laws relating particularly 1D samples to 3D population power-law exponents, with differences between expected and observed values of up to 0.25. The stochastic model is used to generate input for a 2D discrete fracture flow model for the case where minor (isotropic) fault permeability is four orders of magnitude lower than that of the host rock and, thus, forms partial barriers to flow. The flow model is used to explore the impact of fault damage zones on bulk fault permeability. The damage zone is shown to be around 50% efficient, i.e. a simple estimate of bulk permeability can be made using the harmonic average of fault rock and host-rock permeability weighted by thickness in 1D traverses (e.g. core, well logs), where only half the observed thickness of fault rock in the fault damage zone is assumed. Considering the contributions of the damage zone and the major slip zone, the fault damage zone is likely to make a significant contribution to the bulk permeability of the fault as a whole when the permeability of minor faults in the damage zone is similar to, or at most, one order of magnitude greater than that of the slip zone fault rocks.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER
  • 5
    facet.materialart.
    Unknown
    Petrophysical characterization of the Sherwood Sandstone from East Yorkshire, UK (2007)
    In:  Geological Society Special Publication 263: 103-118.
    Details
    Publication Date: 2007-10-08
    Description: Petrophysical tests were conducted on core samples from the unsaturated zone of the Sherwood Sandstone Group in East Yorkshire. Tests were conducted to determine which physical parameters most influenced its hydraulic conductivity values. The main parameters analysed were grain-size distribution, pore-throat size distribution, clay content, mineralogy and porosity. A constant flow rate permeameter was used to measure saturated hydraulic conductivity values in the vertical direction (perpendicular to lamination), Kv, and horizontal direction (parallel to lamination), Kh. Hydraulic conductivity values in the vertical direction, Kv, ranged from 0.004 to 0.12 m day-1 while values in the horizontal direction, Kh, ranged from 0.01 to 0.17 m day-1. Hydraulic conductivity anisotropy, Kh/Kv, varied from 0.6 to 35. Scanning electron microscope analysis showed this anisotropy to be caused mainly by millimetre-scale laminations. Representative bulk hydraulic conductivity values were estimated from the core data; bulk horizontal hydraulic conductivity, Khb, was estimated as 0.1 m day-1, and bulk vertical hydraulic conductivity, Kvb, as 0.01 m day-1. Principal components analysis and multiple regression analysis were used to determine parameters that affect hydraulic conductivity most. Grain sorting is established to be the most important parameter to influence Kv values; samples with fine laminations have relatively low Kv.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER
  • 6
    facet.materialart.
    Unknown
    Rapid karstic bypass flow in the unsaturated zone of the Yorkshire chalk aquifer and implications for contaminant transport (2007)
    In:  Geological Society Special Publication 279: 111-122.
    Details
    Publication Date: 2007-10-08
    Description: Tracer tests have been performed on the unsaturated zone of the East Yorkshire chalk aquifer, UK. Rapid tracer travel times through significant thicknesses of unsaturated chalk (15-38 m) indicate that bypass flow must occur through fractures. Transport processes in the unsaturated zone of the chalk aquifer thus have similarities to those in the vadose zone of more typically karstic limestone aquifers. Modelling of tracer breakthrough curves indicates that bypass flow is sufficiently rapid to significantly inhibit diffusional loss of tracer into the porous matrix of the chalk. The presence of rapid karstic bypass flow in the unsaturated zone of the chalk will limit the potential for attenuation of groundwater contaminants in this zone.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER
  • 7
    facet.materialart.
    Unknown
    Models of tracer breakthrough and permeability in simple fractured porous media (2007)
    In:  Geological Society Special Publication 249: 91-102.
    Details
    Publication Date: 2007-10-08
    Description: Tailing and bimodal behaviour of tracer breakthrough curves from tracer tests conducted in fractured porous media are commonly presented as deviations' from the Fickian model for homogeneous porous media. Tailing is mainly attributed to: (1) tracer storage brought about by diffusion between mobile and static regions of fluid; (2) a concentration of flow towards the wider (aperture) and, thus, more permeable fracture zones; and (3) the high variance in fracture conductivity and consequent mixing of tracer. Bi- (or multi-) modality has been attributed to solute following a few highly permeable flow paths. Systematic numerical simulations of flow and transport in geometrically simple fractured porous media were conducted using a 2D finite difference flow code and a particle tracking transport model. As a simplification only advective dispersion was considered. The modelling study produced a large variety of tracer breakthrough curves, including two patterns commonly seen in field data -- the backward tailed uni-modal type and the Gaussian type. The study demonstrates that different types of breakthrough might be characteristic of particular sets of conceptual models for heterogeneities and, as such, may provide a useful pointer in the application and interpretation of tracer tests.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER
  • 8
    facet.materialart.
    Unknown
    Convergent Flow in Unsaturated Fractured Chalk (2012)
    Soil Science Society of America (SSSA)
    Details
    Publication Date: 2012-11-28
    Description: The Cretaceous Chalk in Northern Europe and other similar fractured rock aquifers frequently have very thick unsaturated (vadose) zones which control both their hydraulic response to rainfall and the extent to which pollutants are delayed or attenuated before reaching groundwater. Understanding their hydraulic responses is a prerequisite for prediction of future trends in groundwater recharge and quality. Accurate characterization of these responses remain elusive because of difficulties in both obtaining in situ measurements and in devising appropriate conceptual models of flow processes in unsaturated fractured rock. In this study we addressed both issues by simultaneously monitoring soil water dynamics through continuously logged matric potential and moisture content and measuring discharge into a subsurface tunnel at up to 45 m depth within the unsaturated zone of Cretaceous Chalk in northern England. Winter drainage fluxes from the base of the soil zone were estimated using the HYDRUS code for one-dimensional variably saturated media. Comparison of soil zone drainage representing the hydraulic input into the Chalk unsaturated zone with tunnel discharge provides insights into the flow dynamics of the unsaturated zone. The relative magnitudes of the soil drainage and deeper unsaturated zone discharge show that flow pathways converge resulting in increased flow focusing with depth in the unsaturated zone. The observed short lag times between the soil surface and the inflow sites in the subsurface tunnel suggest that contaminants from the surface could rapidly reach the water table through thick unsaturated zones within the Chalk.
    Electronic ISSN: 1539-1663
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Soil Science Society of America (SSSA)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Scaling of fracture systems in geological media (2001)
    American Geophysical Union
    Details
    Publication Date: 2001-08-01
    Print ISSN: 8755-1209
    Topics: Geosciences
    Published by American Geophysical Union
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Variations in fracture system geometry and their implications for fluid flow in fractures hydrocarbon reservoirs (1999)
    Geological Society of London
    Details
    Publication Date: 1999-11-01
    Print ISSN: 1354-0793
    Electronic ISSN: 2041-496X
    Topics: Chemistry and Pharmacology , Geosciences
    Published by Geological Society of London
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...