- Email: [email protected]
Die geologische Barriere aus der Sicht der Mineralogie, sedimentologie und geochemie (Geological barriers - mineralogical, sedimentological and geochemical aspects)
PROPERTIES:PERMEABILITY & CAPILLARITY 944107 Retention de i'eau par les materiaux argileux: signification et prevision (Water retention by clayey materials: significance and prediction) G.-H. Sala & D. Tessier, Comptes Rendus - Academic des
Sciences, Serie H: Sciences de la Terre et des Planetes, 318(3), 1994, pp 381-388. The following equation descri_bes water retention in claye2~ materials: VM.' = 1.24 ~ ° - a Log (S/So). The .V.. ~e_ constant depends principally on the pore space delimited by the clay matrix, and is calculated from the water content at a suction pressure of 100 kPa. The coefficient a is more directly related to the submacroscopic organization of the materials and their energetic history. There is an abridged English version. -English summary
944108 Changes in the permeability, streaming potential and resistivity of a claystone from the Nankai prism under stress L. Jouniaux, S. Lallemant & J.-P. Pozzi, Geophysical Research Letters, 21(2), 1994, pp 149-152. Permeability is the critical factor governing fluid flow in accretionary prisms. Accretionary wedges are highly deformed, so permeability changes in an indurated claystone sample from the Nankal accretionary prism were measured during a triaxial stress experiment by the pulse decay method. Three zones were identified from the loading test. In zone I, the sample has deformed less than 1.3% and its permeability was 5"×10-2o m 2. In zone H, the deformation reached 1.5% and the permeability was unstable with time. In zone HI, the sample deformatlon reached 2% and its permeability reached 3x8 10-re m 2. The experiments suggest that shear deformation under low effective pressure increased the vertical permeability of sediments above the decollement. This increase in permeability may be detected by measuring the streaming potential. -from Authors
944109 Computation of porosity redistribution resulting from thermal convection in slanted porous layers P. Gouze, A. Coudraln-Ribetein & D. Bernard, Journal of Geophysical Research, 99(B 1), 1994, pp 697-706. Unlike fluid displacement due to regional hydraulic head, thermoconvective motions are generally slow. The thermal impacts of such movements are very weak, whereas their chemical impacts may be significant because of their cumulated effects over geological time. For nonhorizontal thick sedimentary reservotrs, the fluid velocity due to thermal convection can be accurately approximated by an explicit function of the dip of the reservoir, the permeability and the difference in thermal conductivity between the aquifer and the confining beds. As the fluid velocity is small, the major rock-forming minerals control the fluid composition by thermodynamic equilibrium. Thus, whereas the volume of redistributed minerals depends on the volume of water circulated, the localization of porosity, enhancement is strongly controlled by the reservoxr mineralogy. -from Authors
944110 Die geologische Barriere aus der Sicht der Mineralogie, Sedimentologie und Geochemie (Geological Barriers - mineralogical, sedimentological and geochemical aspects) F.-J. Eckhardt, Zeitschrifl fur Angewandte Geologie, 39(2), 1993, pp 57-62. Mineralogical methods and mineralogical data are being increasingly used in the geotechnical evaluation of the permeability of rocks and of barrier rocks for waste disposal sites. A few examples are taken to demonstrate the diverse ways in which the mineralogy of a rock can influence its efficiency as a barrier. The difficulties and limits of quantitative mineralogical analysis of clay minerals are di~cussed. A semiquantitative method combining XRD and XRF. -from English summary
187A
944111 ln.situ-Bestimmung des vertikalen Durchlassigkeitsheiwerts yon Kiei durch Auswertung der Tidefortpfianzung (In-situ determination of the vertical hydraulic conductivity of a perimarine clay on the basis o f the propagation of the tide through the clay) P. Doll, W. Neumann-Peters, J. Kroger & W. Schneider, Zeitschrifl fur Angewandte Geologic, 39(2), 1993, pp 83-90. The vertical hydraulic conductivity of a perimarine clay that covers the marsh areas in northern Germany, Denmark, Great Britain and the Netherlands was determined by measuring the propagation of the tide from the underlying aquifer into the clay. Only by usin$ porous cup tenalometers instead of piezometers was xt possible to measure these rapid pore water pressure changes. At the scale of the test field (20 m), two well-defined zones of hydraulic_conductivity were observed, with mean values of 5.5"10"y m/s and 2.2"10 "s m/s. These values are much larger than the values from percolation columns in the lab. -English summary 944112 Pore fluid effects on seismic velocity in anisotropic rocks T. Mukerji & G. Mavko, Geophysics, 59(2), 1994, pp 233-244. A simple new technique predicts the high- and low-frequency saturated velocities in anisotropic rocks entirely in terms of measurable dry rock properties without the need for idealized crack geometries. Measurements of dry velocity versus pressure and porosity versus pressure contain all of the necessary information for predicting the frequency-dependent effects of fluid saturation. Furthermore, these measurements automatically incorporate all pore interaction, so there is no limitation to low crack density. The velocities are found to depend on five key lurch'elated variables: frequency, the distribution of compliant cracklike porosity, the intrinsic or noncrack auisotropy, fluid viscosity and compressibility, and effective pressure. The sensitivity of velocities to saturation is generally greater at high frequencies than low frequencies. -from Authors 944113 Generalized cokriging of porosity prediction from seismic data (in Chinese) Sun Shu-Hai & Liu Xue-Ying, Acta Geophysica Sinica, 36(6), 1993, pp 798-804. Generalized cokriging of porosity prediction from seismic data has been developed as an improvement to simple cokriging developed by Doyen, and its fundamental formulae are inferred and proved in detail. The areal distribution of porosity is estimated in the Fuyu gas-bearing sand reservoir of Songzhan area in Songliao basin. -from English summary 944114 Minimum thickness of compacted soil liners: I. Stochastic models C. H. Benson & D. E. Daniel, Journal of Geotechnical Engineering- ASCE, 120(1), 1994, pp 129-152. Regulatory agencies often specify a minimum thickness of compacted soil liners that will ensure that the liner performs adequately. No consensus has been formed, however, on an appropriate minimum thickness. In this paper two models o f fluid flow in compacted soil liners are described. These models incorporate flow in macropores, spatial variability, and uncertainty via probability theory, but only consider advective transport in saturated soil. In the second paper, the models are used to identify an appropriate minimum thickness of soil liners. -from Authors 944115 Minimum thickness of compacted soil liners: II. Analysis and case histories C. H. Benson & D. E. Daniel, Journal of Geotechnical Engineering -ASCE, 120(1), 1994, pp 153-172. Stochastic models were used to analyze compacted soil liners with a variable number of 15 cm (6 in.) thick lifts. No optimum number of lifts could be defined based on first-passage time; first-passage time increased as the thickness increased. Both models showed that the flux through the liner and the equivalent hydraulic conductivity decreased as the mean hydraulic conductivity (modeled as a lognormally distributed random variable) of lifts
Sciences, Serie H: Sciences de la Terre et des Planetes, 318(3), 1994, pp 381-388. The following equation descri_bes water retention in claye2~ materials: VM.' = 1.24 ~ ° - a Log (S/So). The .V.. ~e_ constant depends principally on the pore space delimited by the clay matrix, and is calculated from the water content at a suction pressure of 100 kPa. The coefficient a is more directly related to the submacroscopic organization of the materials and their energetic history. There is an abridged English version. -English summary
944108 Changes in the permeability, streaming potential and resistivity of a claystone from the Nankai prism under stress L. Jouniaux, S. Lallemant & J.-P. Pozzi, Geophysical Research Letters, 21(2), 1994, pp 149-152. Permeability is the critical factor governing fluid flow in accretionary prisms. Accretionary wedges are highly deformed, so permeability changes in an indurated claystone sample from the Nankal accretionary prism were measured during a triaxial stress experiment by the pulse decay method. Three zones were identified from the loading test. In zone I, the sample has deformed less than 1.3% and its permeability was 5"×10-2o m 2. In zone H, the deformation reached 1.5% and the permeability was unstable with time. In zone HI, the sample deformatlon reached 2% and its permeability reached 3x8 10-re m 2. The experiments suggest that shear deformation under low effective pressure increased the vertical permeability of sediments above the decollement. This increase in permeability may be detected by measuring the streaming potential. -from Authors
944109 Computation of porosity redistribution resulting from thermal convection in slanted porous layers P. Gouze, A. Coudraln-Ribetein & D. Bernard, Journal of Geophysical Research, 99(B 1), 1994, pp 697-706. Unlike fluid displacement due to regional hydraulic head, thermoconvective motions are generally slow. The thermal impacts of such movements are very weak, whereas their chemical impacts may be significant because of their cumulated effects over geological time. For nonhorizontal thick sedimentary reservotrs, the fluid velocity due to thermal convection can be accurately approximated by an explicit function of the dip of the reservoir, the permeability and the difference in thermal conductivity between the aquifer and the confining beds. As the fluid velocity is small, the major rock-forming minerals control the fluid composition by thermodynamic equilibrium. Thus, whereas the volume of redistributed minerals depends on the volume of water circulated, the localization of porosity, enhancement is strongly controlled by the reservoxr mineralogy. -from Authors
944110 Die geologische Barriere aus der Sicht der Mineralogie, Sedimentologie und Geochemie (Geological Barriers - mineralogical, sedimentological and geochemical aspects) F.-J. Eckhardt, Zeitschrifl fur Angewandte Geologie, 39(2), 1993, pp 57-62. Mineralogical methods and mineralogical data are being increasingly used in the geotechnical evaluation of the permeability of rocks and of barrier rocks for waste disposal sites. A few examples are taken to demonstrate the diverse ways in which the mineralogy of a rock can influence its efficiency as a barrier. The difficulties and limits of quantitative mineralogical analysis of clay minerals are di~cussed. A semiquantitative method combining XRD and XRF. -from English summary
187A
944111 ln.situ-Bestimmung des vertikalen Durchlassigkeitsheiwerts yon Kiei durch Auswertung der Tidefortpfianzung (In-situ determination of the vertical hydraulic conductivity of a perimarine clay on the basis o f the propagation of the tide through the clay) P. Doll, W. Neumann-Peters, J. Kroger & W. Schneider, Zeitschrifl fur Angewandte Geologic, 39(2), 1993, pp 83-90. The vertical hydraulic conductivity of a perimarine clay that covers the marsh areas in northern Germany, Denmark, Great Britain and the Netherlands was determined by measuring the propagation of the tide from the underlying aquifer into the clay. Only by usin$ porous cup tenalometers instead of piezometers was xt possible to measure these rapid pore water pressure changes. At the scale of the test field (20 m), two well-defined zones of hydraulic_conductivity were observed, with mean values of 5.5"10"y m/s and 2.2"10 "s m/s. These values are much larger than the values from percolation columns in the lab. -English summary 944112 Pore fluid effects on seismic velocity in anisotropic rocks T. Mukerji & G. Mavko, Geophysics, 59(2), 1994, pp 233-244. A simple new technique predicts the high- and low-frequency saturated velocities in anisotropic rocks entirely in terms of measurable dry rock properties without the need for idealized crack geometries. Measurements of dry velocity versus pressure and porosity versus pressure contain all of the necessary information for predicting the frequency-dependent effects of fluid saturation. Furthermore, these measurements automatically incorporate all pore interaction, so there is no limitation to low crack density. The velocities are found to depend on five key lurch'elated variables: frequency, the distribution of compliant cracklike porosity, the intrinsic or noncrack auisotropy, fluid viscosity and compressibility, and effective pressure. The sensitivity of velocities to saturation is generally greater at high frequencies than low frequencies. -from Authors 944113 Generalized cokriging of porosity prediction from seismic data (in Chinese) Sun Shu-Hai & Liu Xue-Ying, Acta Geophysica Sinica, 36(6), 1993, pp 798-804. Generalized cokriging of porosity prediction from seismic data has been developed as an improvement to simple cokriging developed by Doyen, and its fundamental formulae are inferred and proved in detail. The areal distribution of porosity is estimated in the Fuyu gas-bearing sand reservoir of Songzhan area in Songliao basin. -from English summary 944114 Minimum thickness of compacted soil liners: I. Stochastic models C. H. Benson & D. E. Daniel, Journal of Geotechnical Engineering- ASCE, 120(1), 1994, pp 129-152. Regulatory agencies often specify a minimum thickness of compacted soil liners that will ensure that the liner performs adequately. No consensus has been formed, however, on an appropriate minimum thickness. In this paper two models o f fluid flow in compacted soil liners are described. These models incorporate flow in macropores, spatial variability, and uncertainty via probability theory, but only consider advective transport in saturated soil. In the second paper, the models are used to identify an appropriate minimum thickness of soil liners. -from Authors 944115 Minimum thickness of compacted soil liners: II. Analysis and case histories C. H. Benson & D. E. Daniel, Journal of Geotechnical Engineering -ASCE, 120(1), 1994, pp 153-172. Stochastic models were used to analyze compacted soil liners with a variable number of 15 cm (6 in.) thick lifts. No optimum number of lifts could be defined based on first-passage time; first-passage time increased as the thickness increased. Both models showed that the flux through the liner and the equivalent hydraulic conductivity decreased as the mean hydraulic conductivity (modeled as a lognormally distributed random variable) of lifts