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X-ray tomography visualization and mechanical modelling of swelling shale around the wellbore
16A
941120 Topographic characteristics of laboratory induced shear fractures Chen, G; Spetzler, H Pure Appl Geophys VI40, N1, 1993, P123-135
941124 Viscosity determinations of some frictionally generated silicate melts: implications for fault zone rheology at high strain rates Spray, J G J Geophys Res V98, NB5, May 1993. P8053-8068
Topography of shear fracture surfaces of Westerly granite has been studied using laser profilometry. Fresh fractures from shear under true triaxial loading and shear fractures after frictional sliding under true and conventional triaxial conditions were examined. Power spectra for the rock surfaces are presented. These spectra and those from natural faults differ from spectra resulting from testing of sawcut specimens. Even a small sliding displacement (lt a grain size) led to significant mismatch between paired sliding surfaces in the direction normal to sliding.
Matrix viscosity of a number of frictionally generated silicate clast-melt suspensions has been determined using the method of Shaw (1972) and results modified to account for effects of entrained fragments in order to obtain suspension viscosities. Data are assessed in the light of a frictional model of coseismic melting in which shear thinning and lubrication feedback effects are evaluated, in order to judge viability of fault zone lubrication. Five samples of pseudotachylyte were examined, three natural and two laboratory generated.
Physico-chemical properties See also: 941028
941121 Behavior of clayey soils on drying-wetting paths Fleureau, J M; Kheirbek-Saoud, S; Soemitro, R; Taibi, S Can Geotech J 1/30, N2, April 1993, P287-296 Laboratory tests were carried out on 11 clayey soils from natural loams to pure montmorillonites and kaolinites to determine the main characteristics of the wetting and drying paths and the influence of the initial state of the soil and other factors. Normally consolidated paths have a large saturated domain in which negative pressure is equivalent to an isotropic stress increase. The behaviour of overconsolidated or dried samples depends largely on the range of stresses and negative pressures.
941122 Aqueous fluid connectivity and chemical transport in clinopyroxene-rich rocks Watson, E B; Lupulescu, A Earth Planet Sci Lett Vl17, N1/2, May 1993, P279-294 Experiments using synthetic clinopyroxenes were used to assess the efficacy of fluid-assisted chemical transport in pyroxene-rich crustal rocks. Temperatures in the range 900950 deg C and pressure of 1.5 GPa were applied. Dihedral angle measurements, which characterise fluid wetting behaviour, and experiments studying bulk rock diffusive transport are described. Such transport is enhanced by the presence of a continuous fluid phase and so provides a useful indicator of aqueous fluid connectivity.
941123 Detailed magnetic and opaque petrologic study of a thick tholeiite from the Rajmahal Voicanics, India Nag, D K; Mallik, S B Geophys J Vl12, N1, Jan 1993, P67-73 Magnetic and opaque petrology studies were carried out on specimens taken at fairly close intervals from the upper cooling face to the lower one of a 22m thick basalt lava flow. The flow can be divided into 8m lower and 14m upper sections on the basis of magnetic properties or opaque mineralogy.
941125 Application of a simple model for assessment of underground radionuclide migration. Part 1. Validity of first-order kinetic model approximation Fujikawa, Y; Fukui, M J Hydrol V145, N1/2, May 1993, P125-145 A first-order kinetic model with diffusion equivalent rate parameters is presented as an alternative to the Fickian model for solute diffusion-sorption in geological media. It was developed using temporal moment analysis of breakthrough curves for a parallel fracture system, hollow cylindrical micropores, and a cylindrical solid phase. The validity of the first-order kinetic model approximation in in-situ rock fracture systems is examined and accuracy shown to increase for smaller fracture spacings, longer groundwater residence times, and larger matrix diffusion coefficients, but to be independent of nuclide distribution coefficients.
941126 Application of a simple model for assessment of underground radionuclide migration. Part II. Assessment in rock-fracture systems Fujikawa, Y; Fukui, M J Hydrol V145, N1/2, May 1993, P147-164 Sensitivity analysis is presented of the performance of a geological layer as a barrier to radionuelide migration. A hydrologically static rock-fracture system is first considered. Nuclide concentration in the fractures is evaluated using a simple firstorder kinetic model with diffusion-equivalent rate parameters, described in a companion paper. For comparison, the case with groundwater convection as well as diffusion-sorption in the rock fracture system is also examined.
941127 X-ray tomography visualization and mechanical modelling of swelling shale around the wellbore Onaisi, A; Audibert, A; Bieber, M T: Bailey, L: Denis, J; Hammond, P S Pet Sei Engng V9, N4, July 1993, P313-329 Swelling-induced fracturing of cylindrical samples of Pierre shale in contact with a water-based drilling fluid has been studied using CT. When the mud water and shale activities were equal, no swelling was seen. When the mud water activity was the greater, swelling and large deformations were seen with mainly radial or circular fractures, respectively, for unconfined and confned specimens. A model has been developed to analyse the hydration stresses.
941120 Topographic characteristics of laboratory induced shear fractures Chen, G; Spetzler, H Pure Appl Geophys VI40, N1, 1993, P123-135
941124 Viscosity determinations of some frictionally generated silicate melts: implications for fault zone rheology at high strain rates Spray, J G J Geophys Res V98, NB5, May 1993. P8053-8068
Topography of shear fracture surfaces of Westerly granite has been studied using laser profilometry. Fresh fractures from shear under true triaxial loading and shear fractures after frictional sliding under true and conventional triaxial conditions were examined. Power spectra for the rock surfaces are presented. These spectra and those from natural faults differ from spectra resulting from testing of sawcut specimens. Even a small sliding displacement (lt a grain size) led to significant mismatch between paired sliding surfaces in the direction normal to sliding.
Matrix viscosity of a number of frictionally generated silicate clast-melt suspensions has been determined using the method of Shaw (1972) and results modified to account for effects of entrained fragments in order to obtain suspension viscosities. Data are assessed in the light of a frictional model of coseismic melting in which shear thinning and lubrication feedback effects are evaluated, in order to judge viability of fault zone lubrication. Five samples of pseudotachylyte were examined, three natural and two laboratory generated.
Physico-chemical properties See also: 941028
941121 Behavior of clayey soils on drying-wetting paths Fleureau, J M; Kheirbek-Saoud, S; Soemitro, R; Taibi, S Can Geotech J 1/30, N2, April 1993, P287-296 Laboratory tests were carried out on 11 clayey soils from natural loams to pure montmorillonites and kaolinites to determine the main characteristics of the wetting and drying paths and the influence of the initial state of the soil and other factors. Normally consolidated paths have a large saturated domain in which negative pressure is equivalent to an isotropic stress increase. The behaviour of overconsolidated or dried samples depends largely on the range of stresses and negative pressures.
941122 Aqueous fluid connectivity and chemical transport in clinopyroxene-rich rocks Watson, E B; Lupulescu, A Earth Planet Sci Lett Vl17, N1/2, May 1993, P279-294 Experiments using synthetic clinopyroxenes were used to assess the efficacy of fluid-assisted chemical transport in pyroxene-rich crustal rocks. Temperatures in the range 900950 deg C and pressure of 1.5 GPa were applied. Dihedral angle measurements, which characterise fluid wetting behaviour, and experiments studying bulk rock diffusive transport are described. Such transport is enhanced by the presence of a continuous fluid phase and so provides a useful indicator of aqueous fluid connectivity.
941123 Detailed magnetic and opaque petrologic study of a thick tholeiite from the Rajmahal Voicanics, India Nag, D K; Mallik, S B Geophys J Vl12, N1, Jan 1993, P67-73 Magnetic and opaque petrology studies were carried out on specimens taken at fairly close intervals from the upper cooling face to the lower one of a 22m thick basalt lava flow. The flow can be divided into 8m lower and 14m upper sections on the basis of magnetic properties or opaque mineralogy.
941125 Application of a simple model for assessment of underground radionuclide migration. Part 1. Validity of first-order kinetic model approximation Fujikawa, Y; Fukui, M J Hydrol V145, N1/2, May 1993, P125-145 A first-order kinetic model with diffusion equivalent rate parameters is presented as an alternative to the Fickian model for solute diffusion-sorption in geological media. It was developed using temporal moment analysis of breakthrough curves for a parallel fracture system, hollow cylindrical micropores, and a cylindrical solid phase. The validity of the first-order kinetic model approximation in in-situ rock fracture systems is examined and accuracy shown to increase for smaller fracture spacings, longer groundwater residence times, and larger matrix diffusion coefficients, but to be independent of nuclide distribution coefficients.
941126 Application of a simple model for assessment of underground radionuclide migration. Part II. Assessment in rock-fracture systems Fujikawa, Y; Fukui, M J Hydrol V145, N1/2, May 1993, P147-164 Sensitivity analysis is presented of the performance of a geological layer as a barrier to radionuelide migration. A hydrologically static rock-fracture system is first considered. Nuclide concentration in the fractures is evaluated using a simple firstorder kinetic model with diffusion-equivalent rate parameters, described in a companion paper. For comparison, the case with groundwater convection as well as diffusion-sorption in the rock fracture system is also examined.
941127 X-ray tomography visualization and mechanical modelling of swelling shale around the wellbore Onaisi, A; Audibert, A; Bieber, M T: Bailey, L: Denis, J; Hammond, P S Pet Sei Engng V9, N4, July 1993, P313-329 Swelling-induced fracturing of cylindrical samples of Pierre shale in contact with a water-based drilling fluid has been studied using CT. When the mud water and shale activities were equal, no swelling was seen. When the mud water activity was the greater, swelling and large deformations were seen with mainly radial or circular fractures, respectively, for unconfined and confned specimens. A model has been developed to analyse the hydration stresses.