Contaminant migration through fractured till into an underlying aquifer

145A 913126 Resistivity-recharge relationships - field study Curtis, B; Kelly, W E J Hydroi 1/118, N1-4, Oct 1990, P39-53 Vertical resistivity soundings were made at five Nebraska sites where artificial recharge experiments had been carried out. The measured electrical properties, together with hydraulic conductivity data from the literature and from laboratory and field tests, were used to evaluate relations between electrical and recharge properties of the unsaturated zone. 913127 Electrical heating of oil reservoirs: numerical simulation and field test results Pizarro, J O S; Trevisan, O V J Pet Teclmol V42, N/O, Oct 1990, P1320-1326 Heating of oil bearing formations to enhance oil recovery has been studied analytically and in the field. Four kinds of equation govern the phenomena under consideration: continuity, momentum, energy conservation, and electrical charge conservation. 2D, 2 phase fluid flow in a single layer, low pressure reservoir at shallow depth is modelled using the finite difference method. Results are compared to those of field experiments in the Rio Panon field. 913128 Magnetic hysteresis as a function of low temperature in rocks: evidence for internal stress control of remanence in multidomain and pseudo-single-domain magnetite Hodych, J P Phys Earth Planet Inter 1/64. NI, Not' 1990, P21-36 Earlier workers have demonstrated the importance of internal stresses to controlling remanence of magnetite-bearing rocks. Magnetic hysteresis loops were measured as a function of temperature for a number of magnetite-bearing rocks at temperatures down to -150 deg C, and variations in coercive force and saturated remanence with temperature recorded. Results are discussed considering the effects of internal stresses on coercive force and the potential for estimating these stresses by magnetic methods. 913129 Pore fluid content and void ratio for marine sediments. Technical note Shimizu. M Soils Found V30. N3. Sept 1990. P124-128 Marine sediments contain saline pore fluids. However, pore fluid content and void ratio are often calculated in terms of 'water" content, and effect of salt content is not considered. A simple analysis demonstrates that neglecting the salinity of pore fluids can lead to void ratio underestimation of up to 5%. 913130 Engineering-geological evaluation of Late Eocene clay rocks relative to civil engineering Chokhonelidze, G I: Djavakhishvili, E A; Gadelia, G S Proc 5th International Congress International Association of Engineering Geology, Buenos Aires. 20-25 October 1986 V4. P2181-2184. Publ Rotterdam." A A Balkema. 1990 Engineering geological properties of Late Eocene argillaceous rocks of the Alpine orogeny, common around Tbilisi, Georgia, USSR. are described. The deposits consist of stratified sandstones, aleurolites, argillites and subargillites. The clay rocks

are the weakest. The subargillites are the most prone to weathering, and cohesion of freshly excavated rock can drop to 1/10 of initial value after only a few days exposure. The weathering mechanism is described. Measures to be taken to prevent deterioration of rock during foundation construction are considered.

913131 Experimental measurements on the effects of pressure and temperature on electric properties of natural and synthetic rocks Jing, X D; Daltaban, T S; Archer, J S Proc International Symposium on Rock at Great Depth, Pau, 28-31 August 1989 I,'3, P!357-1367. Publ Rotterdam: A A Balkema, 1989 Characterisation of in situ reservoir rock properties is essential to optimise development. Laboratory testing must be under realistic reservoir conditions. A multi-sample rock testing system and some results from resistivity measurements on sandstones and synthetic rock samples are presented. Effects of pressure and temperature on formation resistivity factor and Archie cementation factor are also reported. A pore space network model is used to study the mechanism of pressure effects on rock properties.

913132 Do quicklime properties depend on limestone structures? An attempt to derive functional connections between selected quantities Butenuth, G; Kasig, W; Frey, M L Proc International Chalk Symposium, Brighton, 4-7 September 1989 P95-102. Publ London: Thomas TelJbrd. 1990 Quicklime is often characterised according to its adiabatic slaking rate, which is influenced by porosity, total surface area, and mass content of free CaO. Quicklimes from 35 samples of Upper Devonian reef structures have been examined to assess any effects of limestone structure on the resultant calcined product. Fossil content and type, silica content (which can immobilise Ca as larnite), and dolomite content were amongst variables investigated. Results are presented and discussed.

913133 Studies of the influence of water on calcite Butenuth, C; De Freitas, M H Proc International Chalk Symposium, Brighton, 4-7 September 1989 P103-108. Publ London: Thomas TelJbrd. 1990 Study of interaction of mineral surfaces with water is essential to fully understanding effects of water on rock mechanical properties. Single surfaces of cleavage rhombs of Iceland Spar were exposed to distilled water at room temperature and atmospheric pressure. Measurements of pH with time suggest that the variation of hydrogen ion concentration can be used as a chemical index of potential for surface change in the presence of water. Leaky Rayleigh wave velocities were measured and provide a means to measure structural changes occurring. The aim is to establish relations between chemical and physical changes with time.

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