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Lotus 1-2-3 diamond drillcore Structural Manipulation spreadsheet: drillcore structural data generation
364A
Presentation and interpretation of data 936249 Lotus 1-2-3 diamond drillcore Structural Manipulation Spreadsheet: drillcore structural data generation Hinman, M
Comput Geosci V19, N3, March 1993, P343-354 Although drillholes are generally oriented by a survey, diamond drillcore is normally unoriented. Where one structural element can be assumed to be reasonably constant in orientation, drillcore can be re-oriented and its structural elements resolved. The SMS automates this procedure where one planar structural element has a constant strike. Rapid generation of large subsurface data sets is possible. Orientations of up to two other planes, two lineations, the intersection lineation between two of the planes, and the apparent dips of the two planes can be calculated.
936250 TOPOVEL: a Fortran program for tomographic inversion of porosity and velocity structure in the subsurface Turgut, A
Comput Geosci 1/19, N4, April 1993, P511-532 Crosshole tomography has become an important geophysics technique. Typically, sources and receivers are placed in two parallel boreholes and first-arrival travel time data are collected between each source and receiver. These data are used to invert the P or S wave velocity structure between the boreholes. The computer program TOPOVEL, which is listed, has been prepared for inversion of 2D P wave velocity or porosity structures between boreholes. Numerical examples are shown.
936251 Reserve estimation using neural network techniques Wu, X; Zhou, Y
Comput Geosci V19, N4, April 1993, P567-575 Techniques for modelling the spatial variation of distribution of ore grade in an exploration area are usually based essentially on geometric reasoning or statistical techniques. Spatial distribution of ore grade as a function of distance is normally assumed. A new approach to this problem is presented based on a multilayer feedforward neural network to capture ore grade distribution. The neural network is directly trained using field assay data at borehole locations. Results obtained compare reasonably well with conventional methods. The main advantage is that no assumptions are made concerning spatial distribution of ore grade.
936253 Anisotropic traveltime tomography Michelena, R J; Muir, F; Harris, J M
Geophys Prospect V41, N4, May 1993, P381-412 The isotropic assumption can lead to serious structural interpretation errors when processing data from anisotropic rock masses. Basic theory and examples are presented of an algorithm for anisotropic traveltime tomography. The algorithm generalises well known inversion techniques by using models discretised into a set of homogeneous elliptically anisotropic cells, chacterised by a vertical and a horizontal slowness. If traveltimes for P, SV, and SH waves from crosshole and VSP tests are available, the procedure proposed can estimate 1D and 2D variations of the elastic constants.
936254 Reflectivity method as a tool for evaluating the seismic response of layered structures Pirera, F; Zanzi, L
J Appl Geophys V30, N1/2, April 1993, P35-41 The reflectivity method is a well known technique for generation of synthetic seismograms which includes the effects of all elastic propagation modes and phenomena. It is limited, in principle, to modelling only of plane layered media. To overcome this restriction, a combination of reflectivity and raytracing methods is suggested. A flow chart for the algorithm applied for the simulations is presented together with a brief description of all extensions included to model the acquisition systems and the noise. Two experiments on crustal models are described and discussed.
936255 Sequential migration-aided reflection tomography: an approach to imaging complex structures Grau, G; Lailly, P
J Appl Geophys V30, N1/2, April 1993, P75-87 Depth imaging of geological structures is important in hydrocarbon exploration using seismies. A major problem is determination of the velocity model. A kinematic approach which explicitly uses and relies on travel time information is presented for this purpose. A recursive scheme is used to increase the amount of information. Available data are processed by tomographic inversion to obtain initial estimates of structural and velocity models matching kinematic information in hand. Prestack depth migration data are then analysed to extract additional information to refine the models.
936252 Combining soil maps with interpolations from point observations to predict quantitative soil properties Heuvelink, G B M; Bierkens, M F P
936256 Seismic diffraction tomography of array data Odegaard, E; Doornbos, J
Geoderma V55, N1/2, Oct 1992, Pl-15
J Geophys Res V98, NB3, March 1993, P4377-4388
Predictions of soil properties from a soil map or from point observations alone are liable to error. A heuristic method is presented for this purpose in which both sources of information are combined, A weighted aYerage is taken of_soitmap predictions and properties obtained by kriging the point observations. Weights are chosen such that accuracy of individual prediction methods is taken into account. Illustration and validation of the technique is undertaken.
A new formulation for diffraction tomography which combines the effects of wave diffraction with ordinary tomography and overcomes some of the fundamental problems of each is a p p l i ~ to a~_~_!ysis~f sh_,a~-period time and amplitude ,-anations across the N O R S A R army. Comparisons are made between images from the standard and modified analyses, which illustrate the improvements possible in resolution of crustal features if the combined approach is used.
© 1993 Pergamon Press Ltd. Reproduction not permitted
Presentation and interpretation of data 936249 Lotus 1-2-3 diamond drillcore Structural Manipulation Spreadsheet: drillcore structural data generation Hinman, M
Comput Geosci V19, N3, March 1993, P343-354 Although drillholes are generally oriented by a survey, diamond drillcore is normally unoriented. Where one structural element can be assumed to be reasonably constant in orientation, drillcore can be re-oriented and its structural elements resolved. The SMS automates this procedure where one planar structural element has a constant strike. Rapid generation of large subsurface data sets is possible. Orientations of up to two other planes, two lineations, the intersection lineation between two of the planes, and the apparent dips of the two planes can be calculated.
936250 TOPOVEL: a Fortran program for tomographic inversion of porosity and velocity structure in the subsurface Turgut, A
Comput Geosci 1/19, N4, April 1993, P511-532 Crosshole tomography has become an important geophysics technique. Typically, sources and receivers are placed in two parallel boreholes and first-arrival travel time data are collected between each source and receiver. These data are used to invert the P or S wave velocity structure between the boreholes. The computer program TOPOVEL, which is listed, has been prepared for inversion of 2D P wave velocity or porosity structures between boreholes. Numerical examples are shown.
936251 Reserve estimation using neural network techniques Wu, X; Zhou, Y
Comput Geosci V19, N4, April 1993, P567-575 Techniques for modelling the spatial variation of distribution of ore grade in an exploration area are usually based essentially on geometric reasoning or statistical techniques. Spatial distribution of ore grade as a function of distance is normally assumed. A new approach to this problem is presented based on a multilayer feedforward neural network to capture ore grade distribution. The neural network is directly trained using field assay data at borehole locations. Results obtained compare reasonably well with conventional methods. The main advantage is that no assumptions are made concerning spatial distribution of ore grade.
936253 Anisotropic traveltime tomography Michelena, R J; Muir, F; Harris, J M
Geophys Prospect V41, N4, May 1993, P381-412 The isotropic assumption can lead to serious structural interpretation errors when processing data from anisotropic rock masses. Basic theory and examples are presented of an algorithm for anisotropic traveltime tomography. The algorithm generalises well known inversion techniques by using models discretised into a set of homogeneous elliptically anisotropic cells, chacterised by a vertical and a horizontal slowness. If traveltimes for P, SV, and SH waves from crosshole and VSP tests are available, the procedure proposed can estimate 1D and 2D variations of the elastic constants.
936254 Reflectivity method as a tool for evaluating the seismic response of layered structures Pirera, F; Zanzi, L
J Appl Geophys V30, N1/2, April 1993, P35-41 The reflectivity method is a well known technique for generation of synthetic seismograms which includes the effects of all elastic propagation modes and phenomena. It is limited, in principle, to modelling only of plane layered media. To overcome this restriction, a combination of reflectivity and raytracing methods is suggested. A flow chart for the algorithm applied for the simulations is presented together with a brief description of all extensions included to model the acquisition systems and the noise. Two experiments on crustal models are described and discussed.
936255 Sequential migration-aided reflection tomography: an approach to imaging complex structures Grau, G; Lailly, P
J Appl Geophys V30, N1/2, April 1993, P75-87 Depth imaging of geological structures is important in hydrocarbon exploration using seismies. A major problem is determination of the velocity model. A kinematic approach which explicitly uses and relies on travel time information is presented for this purpose. A recursive scheme is used to increase the amount of information. Available data are processed by tomographic inversion to obtain initial estimates of structural and velocity models matching kinematic information in hand. Prestack depth migration data are then analysed to extract additional information to refine the models.
936252 Combining soil maps with interpolations from point observations to predict quantitative soil properties Heuvelink, G B M; Bierkens, M F P
936256 Seismic diffraction tomography of array data Odegaard, E; Doornbos, J
Geoderma V55, N1/2, Oct 1992, Pl-15
J Geophys Res V98, NB3, March 1993, P4377-4388
Predictions of soil properties from a soil map or from point observations alone are liable to error. A heuristic method is presented for this purpose in which both sources of information are combined, A weighted aYerage is taken of_soitmap predictions and properties obtained by kriging the point observations. Weights are chosen such that accuracy of individual prediction methods is taken into account. Illustration and validation of the technique is undertaken.
A new formulation for diffraction tomography which combines the effects of wave diffraction with ordinary tomography and overcomes some of the fundamental problems of each is a p p l i ~ to a~_~_!ysis~f sh_,a~-period time and amplitude ,-anations across the N O R S A R army. Comparisons are made between images from the standard and modified analyses, which illustrate the improvements possible in resolution of crustal features if the combined approach is used.
© 1993 Pergamon Press Ltd. Reproduction not permitted