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Borehole techniques identifying subsurface chimney heights in loose ground - some experiences above underground nuclear explosions
SITE INVESTIGATIONS:BOREHOLES special logging protocol was developed to minimize the effects of radon. -Authors
Borehole and core logging 943186 The design, construction, and application of concrete models for calibrating borehole g a m m a - r a y spectrometers R. L. Grasty & Y. B. Blanchard, Bulletin - Geological Survey of Canada, 454, 1993, 14 pp. Sets of four cylindrical model boreholes, 76 cm in diameter by 80 cm deep, and each weighing approximately 900 kg were constructed for calibrating borehole gamma-ray spectrometers. The models were designed to minimize weight and give a 30 cm region of uniform radioactivity along the borehole. Gamma-ray measurements in 76 man diameter holes drilled through the models showed little variation although laboratory analyses of samples of the drill core from the thorium model showed local~ed inhomogeneities. For a 15 min counting time within each model, errors in the calibration constants were found to be small because the models provide almost pure gamma-ray spectra of the three radioelements and their concentrations are reliably known. -from Authors 943187 A neutron activation technique for the analysis of cryolite in core samples U . B . Jayanthi, O. L. Goncalez, A. M. G. Figueiredo, L. S. Y. Rigolon & K. A. Jayanthi, Nuclear Geophysics, 7(4), 1993, pp 515-517. A short-lived, delayed neutron activation technique has been investigated to determine the content of cryolite (Na3A1Ft) in core samples, by the detection of fluorine through the fast neutron reaction 19F(n,ct)I6N. The resultant T-rays in the energy range of 2.84-8.14 MeV measured for pure cryolite and background samples, established that cryolite concentrations >13.6 wt% in rock samples could be estimated with uncertainties of about 4- 4.3 wt%. The results are very satisfactory for exploration purposes. -Authors 943188 GIS procedure for developing three-dimensional subsurface profile C.V. C a m p & M. C. Brown, Journal of Computing in Civil Engineering - ASCE, 7(3), 1993, pp 296-309. A geographic information system based procedure for developing subsurface profiles from well-log data is developed. The well-log data base is constructed from a series of borehole geophysical logs. Interpretationof geophysical and formation well logs is discussed. For each of the denoted subsurface units, a G I S - M O D F L O W interface computes the geohydrologic parameters from the GIS weLilog data base. The well-log data is analyzed and output in a format compatible with the input data structure of the ground-water flow model M O D F L O W . -from Authors 943189 Evolution of downhole measurement systems P. Lysne, J O I D E S Journal, 19(3), 1993, pp 29-31. An often-cited example of the need for technology development arises from the lack of downhole tools statable for use in thermal regimes. But a more general reason for development stems from the nature of scientific drilling in that work is conducted in regions of the Earth's crust that differ from the sedimentary regions of interest to the traditional logging industry. Thus, even well-estabLished tools must be examined for data integrity and information content. Interactions. between scientific drilling programs and industrial mst~tutlons can further this mission at a time when budgetary difficulties are manifest. These interactions will require guarantees that evolutionary systems are useful and practical; guidelines addressing such quality issues are under development within the Ocean Drilling Program. -Author 943190 A transmission-line model for electrical logging through casing A . A . Kaufman & W. E. Wightman, Geophysics, 58(12), 1993, pp 1739-1747. Electrical logging in cased holes is a subject of strong current interest. This paper develops the conventional
145A
theory of physical responses of electricallogging through casing where the formation resistivitychanges vertically and where the conductance of the casing varies.The theory is developed for a four-~lectrode sonde with one current electrode, and three receiver electrodes that measure current leakage into the formation. It was established that measurement of apparent conductivity can be made accurately inside a casing of finite length when it essentially exceeds the length of the electrode array. The results show that electrical logging through casing is possible in wells with conventional casing strings that penetrate layered sedimentary formations. -from Authors 943191 Rock mechanics in the 1990s: borehole instability and breakouts ed B. C. Haimson, International Journal of Rock Mechanics and Mining Sciences, 30(7), 1993, pp 1027-1118. These papers were originally presented at the 34th US Symposium on Rock Mechamcs, June 1993. Fifteen papers examine the influence of a wide variety of stress regtmes and geological settings on borehole stability. One paper presents a new hypothesis to explain borehole breakout stability. -R.Gower 943192
Chinese)
Interactive intelligent well logs correlation (in
Li Nan, Li Yan-Da & Chang Tong, Acta Geophysical
Sinica, 36(4), 1993, pp 537-543. An interactive processing model is established for geophysical signal correlation. Several signal matching algorithms axe studied, improved and installed. Knowledge and experience from studies and human judgement are condensed into rule-based processing. A hierarchical processhag structure is designed to combine various algorithms and to conduct parameters decision in an optimal datadriven way. Information of related sources and human evaluation is integrated to better define the problem. Tests on well logs give acceptable performance. -from English summary 943193 Borehole techniques identifying subsurface chimney heights in loose g r o u n d - some experiences above u n d e r g r o u n d nuclear explosions R . D . Carroll & J. W. Lacomb, International Journal of Rock Mechanics & Mining Sciences, 30(6), 1993, pp 575-590. The location of the subsurface tol~ of the chimney formed by the collapse of the cavity resulting from an underground nuclear explosion is examined at five sites at the Nevada Test Site. The chimneys were investigated by drilling, coring, geophysical logging, and seismic velocity surveys. The identincation of the top of the chimney can be complicated by chimney termination in friable volcanic rock of relatively high porosity. Thepresence of an apical void in three of the five cases is confitrmed as the chimney horizon by coincidence with anomalies observed in coring, caliper and gamma-ray logging (two-eases), seismic velocity, and drilling. Of all indicators, core recovery and seismic velocity indicate anomalous horizons in every case. Because radiation products associated with the explosion are contamed within the immediate vicinity of the cavity, gammaray logs are generally not diagnostic of chimney penetration. In no case is the density log indicative of the presence of the chimney. -from Authors
943194 Site investigation techniques for piled foundations in Mercia Mudstones, Teeside, Cleveland County G. M. Reeves, J. Hilary & D. Screaton, in: The engineering geology of weak rock. Prec. conference, Leeds, 1990, ed J.C. Cripps & others, (Balkema; ~.ngineering Geology S p e c i a l PubLication, 8), 1993, pp 457-463. In order to sample and assess the quality of Mercia Mudstone in parts of Teesside for thelocation and design of rock socketed end bearing piles, specialised triple-tubed core drillin.g and sampling techniques have been required to a conslaerable depth below the predicted rockhead level. These techniques are described and the nature of the soft, highly weathered mudrocks discussed in the context
Borehole and core logging 943186 The design, construction, and application of concrete models for calibrating borehole g a m m a - r a y spectrometers R. L. Grasty & Y. B. Blanchard, Bulletin - Geological Survey of Canada, 454, 1993, 14 pp. Sets of four cylindrical model boreholes, 76 cm in diameter by 80 cm deep, and each weighing approximately 900 kg were constructed for calibrating borehole gamma-ray spectrometers. The models were designed to minimize weight and give a 30 cm region of uniform radioactivity along the borehole. Gamma-ray measurements in 76 man diameter holes drilled through the models showed little variation although laboratory analyses of samples of the drill core from the thorium model showed local~ed inhomogeneities. For a 15 min counting time within each model, errors in the calibration constants were found to be small because the models provide almost pure gamma-ray spectra of the three radioelements and their concentrations are reliably known. -from Authors 943187 A neutron activation technique for the analysis of cryolite in core samples U . B . Jayanthi, O. L. Goncalez, A. M. G. Figueiredo, L. S. Y. Rigolon & K. A. Jayanthi, Nuclear Geophysics, 7(4), 1993, pp 515-517. A short-lived, delayed neutron activation technique has been investigated to determine the content of cryolite (Na3A1Ft) in core samples, by the detection of fluorine through the fast neutron reaction 19F(n,ct)I6N. The resultant T-rays in the energy range of 2.84-8.14 MeV measured for pure cryolite and background samples, established that cryolite concentrations >13.6 wt% in rock samples could be estimated with uncertainties of about 4- 4.3 wt%. The results are very satisfactory for exploration purposes. -Authors 943188 GIS procedure for developing three-dimensional subsurface profile C.V. C a m p & M. C. Brown, Journal of Computing in Civil Engineering - ASCE, 7(3), 1993, pp 296-309. A geographic information system based procedure for developing subsurface profiles from well-log data is developed. The well-log data base is constructed from a series of borehole geophysical logs. Interpretationof geophysical and formation well logs is discussed. For each of the denoted subsurface units, a G I S - M O D F L O W interface computes the geohydrologic parameters from the GIS weLilog data base. The well-log data is analyzed and output in a format compatible with the input data structure of the ground-water flow model M O D F L O W . -from Authors 943189 Evolution of downhole measurement systems P. Lysne, J O I D E S Journal, 19(3), 1993, pp 29-31. An often-cited example of the need for technology development arises from the lack of downhole tools statable for use in thermal regimes. But a more general reason for development stems from the nature of scientific drilling in that work is conducted in regions of the Earth's crust that differ from the sedimentary regions of interest to the traditional logging industry. Thus, even well-estabLished tools must be examined for data integrity and information content. Interactions. between scientific drilling programs and industrial mst~tutlons can further this mission at a time when budgetary difficulties are manifest. These interactions will require guarantees that evolutionary systems are useful and practical; guidelines addressing such quality issues are under development within the Ocean Drilling Program. -Author 943190 A transmission-line model for electrical logging through casing A . A . Kaufman & W. E. Wightman, Geophysics, 58(12), 1993, pp 1739-1747. Electrical logging in cased holes is a subject of strong current interest. This paper develops the conventional
145A
theory of physical responses of electricallogging through casing where the formation resistivitychanges vertically and where the conductance of the casing varies.The theory is developed for a four-~lectrode sonde with one current electrode, and three receiver electrodes that measure current leakage into the formation. It was established that measurement of apparent conductivity can be made accurately inside a casing of finite length when it essentially exceeds the length of the electrode array. The results show that electrical logging through casing is possible in wells with conventional casing strings that penetrate layered sedimentary formations. -from Authors 943191 Rock mechanics in the 1990s: borehole instability and breakouts ed B. C. Haimson, International Journal of Rock Mechanics and Mining Sciences, 30(7), 1993, pp 1027-1118. These papers were originally presented at the 34th US Symposium on Rock Mechamcs, June 1993. Fifteen papers examine the influence of a wide variety of stress regtmes and geological settings on borehole stability. One paper presents a new hypothesis to explain borehole breakout stability. -R.Gower 943192
Chinese)
Interactive intelligent well logs correlation (in
Li Nan, Li Yan-Da & Chang Tong, Acta Geophysical
Sinica, 36(4), 1993, pp 537-543. An interactive processing model is established for geophysical signal correlation. Several signal matching algorithms axe studied, improved and installed. Knowledge and experience from studies and human judgement are condensed into rule-based processing. A hierarchical processhag structure is designed to combine various algorithms and to conduct parameters decision in an optimal datadriven way. Information of related sources and human evaluation is integrated to better define the problem. Tests on well logs give acceptable performance. -from English summary 943193 Borehole techniques identifying subsurface chimney heights in loose g r o u n d - some experiences above u n d e r g r o u n d nuclear explosions R . D . Carroll & J. W. Lacomb, International Journal of Rock Mechanics & Mining Sciences, 30(6), 1993, pp 575-590. The location of the subsurface tol~ of the chimney formed by the collapse of the cavity resulting from an underground nuclear explosion is examined at five sites at the Nevada Test Site. The chimneys were investigated by drilling, coring, geophysical logging, and seismic velocity surveys. The identincation of the top of the chimney can be complicated by chimney termination in friable volcanic rock of relatively high porosity. Thepresence of an apical void in three of the five cases is confitrmed as the chimney horizon by coincidence with anomalies observed in coring, caliper and gamma-ray logging (two-eases), seismic velocity, and drilling. Of all indicators, core recovery and seismic velocity indicate anomalous horizons in every case. Because radiation products associated with the explosion are contamed within the immediate vicinity of the cavity, gammaray logs are generally not diagnostic of chimney penetration. In no case is the density log indicative of the presence of the chimney. -from Authors
943194 Site investigation techniques for piled foundations in Mercia Mudstones, Teeside, Cleveland County G. M. Reeves, J. Hilary & D. Screaton, in: The engineering geology of weak rock. Prec. conference, Leeds, 1990, ed J.C. Cripps & others, (Balkema; ~.ngineering Geology S p e c i a l PubLication, 8), 1993, pp 457-463. In order to sample and assess the quality of Mercia Mudstone in parts of Teesside for thelocation and design of rock socketed end bearing piles, specialised triple-tubed core drillin.g and sampling techniques have been required to a conslaerable depth below the predicted rockhead level. These techniques are described and the nature of the soft, highly weathered mudrocks discussed in the context