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Coal seam mapping by analysis of direct channel wave arrivals
126A 883178 Estimation of coal measares rock strength esiag senic and
neutron logs McNally, G H Geoexpioration V24, 3/4/5, Nov 1987, P381-395 Geophysical logs from 24 drillholes were used to estimate uniaxial compressive strength (UCS). High resolution sonic logs show an exponential relationship with UCS and have proved to be most useful, although neutron logs may indicate strength variations better in massive strata. Neither correlation appears to be site dependent. Other geotechnical applications of downhole logs, and their interpretation, are discussed. 883179
High resolution sebmi¢ rehetioa served for coal Palmer, D Geoexpioratioa V24, N4/5, Nov 1987, P397-408 The Sydney Basin is difficult to survey due to multi-coal seams, friable sandstones and massive, high seismic velocity sandstone. High resolution seismic reflection surveys, using 48 trace IFP recording equipment, show significant improvement over existing methods, especially since they detect direction of movement and width of the disturbed zone, although difficulties remain for faults with small displacements. At Victoria Park,clear fault mapping and extended penetration of seismic energy have been achieved, whilst at Glennies Creek steep dip of the seam due to wedging of sediments was discovered. 883180
Coal seam mal~ai~ by analysis of direct channel wave arrivals Hatherly, P J; Hornby, P; Irwin, P F Geoexpioratioa V24, ]¢4/5, Nov 1987, P421-427 Faults block the passage of channel waves propagating within coal seams. In Australia exploration borehole drilling is routine, so borehole to borehole surveys could he useful. However, results of such in-seam seismic surveys are unsatisfactory since the seams act as thick wavegnides with high absorption. At Glennies Creek the whole seam sequence is acting as a waveguide, making high frequency components associated with individual seams absent. More research is needed as the potential applications of in-seam seismic methods are great. 883181
Weighted stacking for rnek property estimation and detection of gas Smith, G C; Gidiow, P M Geopkys Prospect V35, N9, Nov 1987, P993-1014 Using conventional seismic 2-d and 3-d data, it is possible to obtain information about P-wave velocity reltectivity, S-wave velocity reflectivity, Poisson's ratio reflectivity and the presence of gas, or oil capped by gas. An analytical method (GeoStack) is outlined, based on simplified Zoeppritz equations. The procedure is tested for a synthetic example and a gas field area. 883182
EnsfmedaSjeopbys~d munu of the LovJ~ n u d ~ power Ronhiainen, P J Gcoplws Prospect V35, N9, Nov 1987, P1015-1029 The geometry and properties of the granitic bedrock below Loviisa power plant were evaluated for suitabifity for storing low- and intermediate-level radioactive waste. Dipmeters were
used to determine location and orientation of fractures, and these results, along with acoustic velocity measurements, were used to plot equal area projections. The seismic crosshole and mise-a-la-masse methods were used to evaluate the geometry and continuity of fracture zones between the boreholes.
883183
3"~m~z.e~m~ l n ~
of p't, Jty data from
sedimentary basins ruing an e x ~ demity-4eiXh funeelea Granser, H Geopkys Prospect V35, N9, Nov 1987, P1030-1041 A relation between density and depth for sedimentary rocks is proposed, which can be incorporated into analyses of gravity data from three dimensional structures to improve accuracy of interpretation. Its use on a 2D synthetic sample and a 3D field example is illustrated.
883184
gx~
of ~
~
fur ~ a m
Fitterman, D V Groud Water V25, N6, Nov-Dec 1987, P685-692 The transient electromagnetic sounding method is described and common interpretational problems disctmed. ~ f i e l d examples of its use are given: groundwater exploration in an alluvium filled basin; mapping a confined, fresh water aquifer in sedimentary rocks; and locating a fresh water/salt ~water interface in a glacial outwash aquifer.
883185
G e n ~ y s i ~ stndy of gerry Read orebe~, Bowker, A M; Hill, I A 7rus imt Min Mttail (Sect B ~ Sci) V96. Nov 1987, PB213-B220 Examination of a conductive stratiform sohist ~ s i t a massive Cu-Zn-Au mineralization is ~ b e d .
M ~ , horizontal loop, pulse and VLF e l e c t r o ~ methods, ~ potential, resistivity and induced polarization techniques were used. All methods indicated out~ropping mim:faligation, but buried mineralization overlain by conductive overburden was only detectable by a combination of teohniqnes. Correlation between known geology and geophysical data is good.
883186
Ai~katlen of VLF,EM on the ~
of
strucem~ In a dam fomdatlea
Chamon, N, Pupo, G; Naka#ato, N; Scarmmio, M
Proc ~tJ ~
~ ~ ~ q " C~oi~,p, ~ Ai~s, 20,25 ~ In P1061-1065. Pub! Rotterdam: A A Balkema, i986
V2,
VLF-EM electromagnetic, seismic refraction, and resistivity methods were used to investigate the C.achoeira Porteira site, Brazil. The rarely used VI.,F.EM ~ w a s CoYed to determine vertical and subvertical stntctures, ~ h as faults, shear zones, veins, and dykes, It was ~ in o v e r ~ depths to 20m, and apt for the moist, porous, ~ weathered rock encountered. ~ use of c o m p l e m e n ~ geophy#ical methods allowed geological futures to be ~ d ~ , and more precise information was obtained by m e c h ~ a l investigation.
© 1988 Pergamon Press plc. Reproduction not permitted
neutron logs McNally, G H Geoexpioration V24, 3/4/5, Nov 1987, P381-395 Geophysical logs from 24 drillholes were used to estimate uniaxial compressive strength (UCS). High resolution sonic logs show an exponential relationship with UCS and have proved to be most useful, although neutron logs may indicate strength variations better in massive strata. Neither correlation appears to be site dependent. Other geotechnical applications of downhole logs, and their interpretation, are discussed. 883179
High resolution sebmi¢ rehetioa served for coal Palmer, D Geoexpioratioa V24, N4/5, Nov 1987, P397-408 The Sydney Basin is difficult to survey due to multi-coal seams, friable sandstones and massive, high seismic velocity sandstone. High resolution seismic reflection surveys, using 48 trace IFP recording equipment, show significant improvement over existing methods, especially since they detect direction of movement and width of the disturbed zone, although difficulties remain for faults with small displacements. At Victoria Park,clear fault mapping and extended penetration of seismic energy have been achieved, whilst at Glennies Creek steep dip of the seam due to wedging of sediments was discovered. 883180
Coal seam mal~ai~ by analysis of direct channel wave arrivals Hatherly, P J; Hornby, P; Irwin, P F Geoexpioratioa V24, ]¢4/5, Nov 1987, P421-427 Faults block the passage of channel waves propagating within coal seams. In Australia exploration borehole drilling is routine, so borehole to borehole surveys could he useful. However, results of such in-seam seismic surveys are unsatisfactory since the seams act as thick wavegnides with high absorption. At Glennies Creek the whole seam sequence is acting as a waveguide, making high frequency components associated with individual seams absent. More research is needed as the potential applications of in-seam seismic methods are great. 883181
Weighted stacking for rnek property estimation and detection of gas Smith, G C; Gidiow, P M Geopkys Prospect V35, N9, Nov 1987, P993-1014 Using conventional seismic 2-d and 3-d data, it is possible to obtain information about P-wave velocity reltectivity, S-wave velocity reflectivity, Poisson's ratio reflectivity and the presence of gas, or oil capped by gas. An analytical method (GeoStack) is outlined, based on simplified Zoeppritz equations. The procedure is tested for a synthetic example and a gas field area. 883182
EnsfmedaSjeopbys~d munu of the LovJ~ n u d ~ power Ronhiainen, P J Gcoplws Prospect V35, N9, Nov 1987, P1015-1029 The geometry and properties of the granitic bedrock below Loviisa power plant were evaluated for suitabifity for storing low- and intermediate-level radioactive waste. Dipmeters were
used to determine location and orientation of fractures, and these results, along with acoustic velocity measurements, were used to plot equal area projections. The seismic crosshole and mise-a-la-masse methods were used to evaluate the geometry and continuity of fracture zones between the boreholes.
883183
3"~m~z.e~m~ l n ~
of p't, Jty data from
sedimentary basins ruing an e x ~ demity-4eiXh funeelea Granser, H Geopkys Prospect V35, N9, Nov 1987, P1030-1041 A relation between density and depth for sedimentary rocks is proposed, which can be incorporated into analyses of gravity data from three dimensional structures to improve accuracy of interpretation. Its use on a 2D synthetic sample and a 3D field example is illustrated.
883184
gx~
of ~
~
fur ~ a m
Fitterman, D V Groud Water V25, N6, Nov-Dec 1987, P685-692 The transient electromagnetic sounding method is described and common interpretational problems disctmed. ~ f i e l d examples of its use are given: groundwater exploration in an alluvium filled basin; mapping a confined, fresh water aquifer in sedimentary rocks; and locating a fresh water/salt ~water interface in a glacial outwash aquifer.
883185
G e n ~ y s i ~ stndy of gerry Read orebe~, Bowker, A M; Hill, I A 7rus imt Min Mttail (Sect B ~ Sci) V96. Nov 1987, PB213-B220 Examination of a conductive stratiform sohist ~ s i t a massive Cu-Zn-Au mineralization is ~ b e d .
M ~ , horizontal loop, pulse and VLF e l e c t r o ~ methods, ~ potential, resistivity and induced polarization techniques were used. All methods indicated out~ropping mim:faligation, but buried mineralization overlain by conductive overburden was only detectable by a combination of teohniqnes. Correlation between known geology and geophysical data is good.
883186
Ai~katlen of VLF,EM on the ~
of
strucem~ In a dam fomdatlea
Chamon, N, Pupo, G; Naka#ato, N; Scarmmio, M
Proc ~tJ ~
~ ~ ~ q " C~oi~,p, ~ Ai~s, 20,25 ~ In P1061-1065. Pub! Rotterdam: A A Balkema, i986
V2,
VLF-EM electromagnetic, seismic refraction, and resistivity methods were used to investigate the C.achoeira Porteira site, Brazil. The rarely used VI.,F.EM ~ w a s CoYed to determine vertical and subvertical stntctures, ~ h as faults, shear zones, veins, and dykes, It was ~ in o v e r ~ depths to 20m, and apt for the moist, porous, ~ weathered rock encountered. ~ use of c o m p l e m e n ~ geophy#ical methods allowed geological futures to be ~ d ~ , and more precise information was obtained by m e c h ~ a l investigation.
© 1988 Pergamon Press plc. Reproduction not permitted