High-resolution shallow seismic reflection surveys using SH-waves

361A 916239 Mobile four-electrode array and its application to the electrical survey of planetary grounds at shallow depths Grard, R; Tabbagh, A J Geophys Res II96, NB3, March 1991, P4117-4123 A mobile array for mapping surface electrical properties is presented. The electrodes, small hanging chains, follow the ground shape exactly. The theoretical background to the technique is outlined. The array was operated at a frequency of 128kHz over a site of low apparent resistivity,20-100 ohm metres. The results were verified by independent measurements with another technique. Measurements at a site of resistivity in the order of kilo-ohm meters indicate that information on dielectric properties can be gathered. The array may be remotely operated and has resolution in the order of a few metres in all directions. 916240 Assessment of halite-cemented reservoir zones Huurdeman, A J M; Breunese, J N; AI-Asbahl, A M S; Lutgert, J E; Floris, F J T J Pet Technol V43, N5, May 1991, P518-523 Techniques used to identify the presence and extent of halitecemented layers in a sandstone reservoir in Yemen are described. Core data are matched with two independent halite identifiers from well logging, pulsed-neutron-log response and three conventional porosity logs (neutron,density, sonic) followed by three-mineral crossplot sections. Numerical well models are used to assess the dimensions and spatial extent of these reduced permeability sections. 916241 Monitoring oil/water fronts by direct measurement Dunlop, K N B; King, G A; Breitenbach, E A J Pet Technoi V43, N5, May 1991, P598-602 A technique to monitor the movement of a fluid-fluid interface in a reservoir by taking the difference between successive seismic surveys is described. Repeated surface seismic reflection surveys of limited extent are made. Acoustic, production, and reservoir data are interpreted by a reservoir simulator to define the fluid interfaces. Field validation and field trial results are discussed. 916242 Detection of underground mined voids using line electrode resistivity technique - a case study Peng, S S; Ziaie, F Min Engr V150, N357, June 1991, P399-403 A new resistivity method using a combination of the Bristow arrangement and line electrode methods is described. Following mathematical simulation and laboratory scale model testing, it was applied at a room and pillar mine site. Results indicated that an entry 1.35m high by 5.40m wide at depth 25.5m could be detected, and superior resolution was seen, compared to conventional resistivity methods. 916243 Radar hazard detection in a coal structure Dennen, R S; Stroud, W P Min Engng V43, N4, April 1991, P413-418 A ground penetrating synthetic pulse radar system was used to map a coal pillar. A velocity image of the interior, obtained by velocity inversion, showed the existence and location of a relatively low velocity region. Core samples revealed the presence of a clay vein coincident with the anomalous layer in the tomograph.

916244 Geophysical methods and instruments for investigation of rocks in coal mines Proskuryakov, V M Proc 1st International Symposium on Mining in the Arctic, Fairbanks, 17-19 July 1989 P83-85. Publ Rotterdam: A ,4 Balkema, 1989 Several geophysical methods can be used to examine state of stresses in coal and orebeds during mining. These include vibroseismic, acoustic emission, and natural electromagnetic radiation methods. All are based on the existence of simple correlations between the parameters of natural or artificially induced physical fields in the rock mass and the changes of stress state in the rock mass. Details are outlined.

916245 Geophysical detection of solution phenomena Deibel, I K Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V2, P921-925. Publ Rotterdam: A A Balkema, 1990 The region around Limberg in the Netherlands is underlain by limestone, and localised solution weathering has produced cylindrical pipes or funnel shaped sinkholes, mostly filled by overlying soil materials. Magnetic (protonmagnetometer) and electromagnetic methods were used in attempts to detect these solution features. Some good results were obtained with electromagnetic techniques. A newly developed computer program (Deibel, 1988) was used for data processing.

916246 Refraction seismic study to determine discontinuity properties in rock-masses Hack, H R G K; Price, D G

Proe 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V2, P935-941. Publ Rotterdam: A A Balkema, 1990 Major causes of anisotropy in rock masses are presence of bedding or patterns of oriented discontinuities or joints. The possibility of estimating this anisotropy using refraction seismics has been examined at quarry sites where surface mapping is possible. Velocity anisotropy functions, velocity optimisation, and velocity ratios are discussed. Fan shooting techniques are seen to be useful for determining directions of rock mass discontinuities.

916247 Application of SH wave reflection method to railway engineering investigation He Zhengi

Proe 6th International Congress International Association of Engineeri~ Geology, Amsterdam, 6-10 August 1990 V2, P949-952. Pubi Rotterdam: A A Balkema, 1990 Seismic reflection methods may be used to determine soil mechanical properties and delineate geological structures at depths to 50m. Areal seismics coupled with penetration, drilling, and loading tests is of particular use. Test procedures, instruments, and data acquisition are described. A case history is presented of engineering geological investigations for a bridge foundation in layered geology.

© 1991 Pergamon Press plc. Reproduction not permitted