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  • Articles  (73)
  • geostatistics  (73)
  • Springer  (73)
  • Blackwell Publishing Ltd
  • Elsevier
  • International Union of Crystallography
  • Taylor & Francis
  • 1995-1999  (25)
  • 1985-1989  (22)
  • 1980-1984  (26)
  • 1930-1934
  • Geosciences  (71)
  • Mathematics  (65)
  • Geography  (2)
  • Political Science
  • Economics
  • Natural Sciences in General
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  • Articles  (73)
Source
Keywords
Publisher
  • Springer  (73)
  • Blackwell Publishing Ltd
  • Elsevier
  • International Union of Crystallography
  • Taylor & Francis
Years
Year
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Geostatistical analysis of longwall face roof convergence data (1989)
    Springer
    Geotechnical and geological engineering 7 (1989), S. 227-237 
    Details
    ISSN: 1573-1529
    Keywords: Roof convergence ; longwall face ; geostatistics ; coal mining ; support advance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Summary Roof convergence and the rate of convergence are regionalized variables; the geostatistics can thus be applied to a set of underground observations. This investigation shows that the removal of a slice of coal induces roof movement. The rate of convergence is highest just after the coal removal and decreases with time. The immediate advance of a ‘rigid’ powered roof support decreases the total convergence for a complete production cycle. On the other hand, the timing of the advance of a relatively ‘soft’ support element has no influence on the total convergence for a complete production cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00880944
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  • 2
    Electronic Resource
    Electronic Resource
    On the importance of choosing a change of support model for global reserves estimation (1988)
    Springer
    Mathematical geology 20 (1988), S. 1001-1019 
    Details
    ISSN: 1573-8868
    Keywords: geostatistics ; change of support ; recoverable reserves ; selectivity ; normality index ; Cartier's formula ; affine correction ; discrete Gaussian model ; mosaic model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The practical problem considered here is: how can block distribution in an orebody be forecast from sample data? The task is arduous because information yielded by samples is too often insufficient to allow an accurate evaluation of blocks. In practice, necessary additional information is obtained via a model. Choosing that model is crucial; the value of results reflects the model, i.e., its adequacy to represent reality. In this paper, the importance of choosing the change of support model is illustrated with simulations and practical examples (especially deposits with a skewed sample distribution and a large spike at the origin). An attempt to quantify this importance is made also.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00892976
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  • 3
    Electronic Resource
    Electronic Resource
    Bayesian updating revisited (1989)
    Springer
    Mathematical geology 21 (1989), S. 285-308 
    Details
    ISSN: 1573-8868
    Keywords: Bayesian updating ; geostatistics ; Kriging ; linear inversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Bayesian updating methods provide an alternate philosophy to the characterization of the input variables of a stochastic mathematical model. Here, a priori values of statistical parameters are assumed on subjective grounds or by analysis of a data base from a geologically similar area. As measurements become available during site investigations, updated estimates of parameters characterizing spatial variability are generated. However, in solving the traditional updating equations, an updated covariance matrix may be generated that is not positive-definite, particularly when observed data errors are small. In addition, measurements may indicate that initial estimates of the statistical parameters are poor. The traditional procedure does not have a facility to revise the parameter estimates before the update is carried out. alternatively, Bayesian updating can be viewed as a linear inverse problem that minimizes a weighted combination of solution simplicity and data misfit. Depending on the weight given to the a priori information, a different solution is generated. A Bayesian updating procedure for log-conductivity interpolation that uses a singular value decomposition (SVD) is presented. An efficient and stable algorithm is outlined that computes the updated log-conductivity field and the a posteriori covariance of the estimated values (estimation errors). In addition, an information density matrix is constructed that indicates how well predicted data match observations. Analysis of this matrix indicates the relative importance of the observed data. The SVD updating procedure is used to interpolate the log-conductivity fields of a series of hypothetical aquifers to demonstrate pitfalls and possibilities of the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00893691
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  • 4
    Electronic Resource
    Electronic Resource
    Factorial kriging analysis applied to geological data from petroleum exploration (1989)
    Springer
    Mathematical geology 21 (1989), S. 683-691 
    Details
    ISSN: 1573-8868
    Keywords: geostatistics ; factorial kriging analysis ; spectral analysis ; petroleum exploration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract A regionalized variable, thickness of the reservoir layer, from a gas field is decomposed by factorial kriging analysis. Maps of the obtained components may be associated with depositional environments that are favorable for petroleum exploration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00893316
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  • 5
    Electronic Resource
    Electronic Resource
    Variography of submarine morphology: Problems of deregularization, and cartographical implications (1989)
    Springer
    Mathematical geology 21 (1989), S. 693-713 
    Details
    ISSN: 1573-8868
    Keywords: geostatistics ; variography ; deregularization ; universal kriging ; bathymetry ; SEABEAM survey ; cartography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract During the German Antarctic Expedition VI (leg 3, December 1987 to March 1988), bathymetric surveys were made in the Weddell Sea by the SEABEAM sonar system. For the first time geostatistical methods were applied in the SEABEAM-postprocessing. The investigations of variography that were necessary prior to the cartographical-geomorphological evaluation shed new light on classical geostatistical concerns. SEABEAM data provide a good example of a mean square, differentiable regionalized variable, where data are sampled over a two-dimensional support due to the technique of the sonar device. By deregularizations of the sample variograms, spatial continuity can be shown to be a property of seafloor depth as well as a point variable. The results are discussed in a sedimentological context. As an application of the regional variogram analyses, large-scale kriged bathymetric maps are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00893317
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  • 6
    Electronic Resource
    Electronic Resource
    Challenges in reservoir forecasting (1996)
    Springer
    Mathematical geology 28 (1996), S. 829-842 
    Details
    ISSN: 1573-8868
    Keywords: geostatistics ; flow simulation ; streamtubes ; scale up ; gridding ; accuracy and precision ; modeling uncertainty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The combination of geostatistics-based numerical geological models and finite difference flow simulation has improved our ability to predict reservoir performance. The main contribution of geostatistical modeling has been more realistic representations of reservoir heterogeneity. Our understanding of the physics of fluid flow in porous media is reasonably captured by flow simulators in common usage. Notwithstanding the increasing application and success of geostatistics and flow simulation there remain many important challenges in reservoir forecasting. This application has alerted geoscientists and physicists that geostatistical/flow models in many respects, are, engineering approximations to thereal spatial distribution andreal flow processes. This paper reviews current research directions and presents some new ideas of where reserach could be focused to improve our ability to model geological features, model flow processes, and, ultimately, improve reservoir performance predictions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02066003
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  • 7
    Electronic Resource
    Electronic Resource
    An Experimental Comparison of Ordinary and Universal Kriging and Inverse Distance Weighting (1999)
    Springer
    Mathematical geology 31 (1999), S. 375-390 
    Details
    ISSN: 1573-8868
    Keywords: geostatistics ; spatial interpolation ; spatial pattern ; surface-fitting algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract A factorial, computational experiment was conducted to compare the spatial interpolation accuracy of ordinary and universal kriging and two types of inverse squared-distance weighting. The experiment considered, in addition to these four interpolation methods, the effects of four data and sampling characteristics: surface type, sampling pattern, noise level, and strength of small-scale spatial correlation. Interpolation accuracy was measured by the natural logarithm of the mean squared interpolation error. Main effects of all five factors, all two-factor interactions, and several three-factor interactions were highly statistically significant. Among numerous findings, the most striking was that the two kriging methods were substantially superior to the inverse distance weighting methods over all levels of surface type, sampling pattern, noise, and correlation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007586507433
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  • 8
    Electronic Resource
    Electronic Resource
    Simulation of Non-Gaussian Transmissivity Fields Honoring Piezometric Data and Integrating Soft and Secondary Information (1999)
    Springer
    Mathematical geology 31 (1999), S. 907-927 
    Details
    ISSN: 1573-8868
    Keywords: conditional probabilities method ; self-calibrated method ; stochastic inversion ; probabilistic assessment ; geostatistics ; stochastic hydrology ; probability fields
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The conditional probabilities (CP) method implements a new procedure for the generation of transmissivity fields conditional to piezometric head data capable to sample nonmulti-Gaussian random functions and to integrate soft and secondary information. The CP method combines the advantages of the self-calibrated (SC) method with probability fields to circumvent some of the drawbacks of the SC method—namely, its difficulty to integrate soft and secondary information or to generate non-Gaussian fields. The SC method is based on the perturbation of a seed transmissivity field already conditional to transmissivity and secondary data, with the perturbation being function of the transmissivity variogram. The CP method is also based on the perturbation of a seed field; however, the perturbation is made function of the full transmissivity bivariate distribution and of the correlation to the secondary data. The two methods are applied to a sample of an exhaustive non-Gaussian data set of natural origin to demonstrate the interest of using a simulation method that is capable to model the spatial patterns of transmissivity variability beyond the variogram. A comparison of the probabilistic predictions of convective transport derived from a Monte Carlo exercise using both methods demonstrates the superiority of the CP method when the underlying spatial variability is non-Gaussian.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007580902175
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  • 9
    Electronic Resource
    Electronic Resource
    The lognormal approach to predicting local distributions of selective mining unit grades (1980)
    Springer
    Mathematical geology 12 (1980), S. 285-303 
    Details
    ISSN: 1573-8868
    Keywords: geostatistics ; lognormal distribution ; mine planning ; ore reserve estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract When planning highly selective mining operations, the challenge is to estimate mineable ore reserves that will be selected at the mining stage. From exploration data it is not possible to estimate accurately the grade (or thickness) of each future selective mining unit; however, it is possible to estimate the local distributions of these mining unit grades within large panels suitable for long-range mine planning. Application of a cut-off then allows estimation of the recovered ore tonnage and grade within each such panel. Derivation of local conditional distributions is rather simple when the grade is either normally or lognormally distributed. The geologically important lognormal case is fully described both in the stationary and the nonstationary case. Cross validations of these techniques using the exploration data of the Imouraren uranium deposit are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01029417
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  • 10
    Electronic Resource
    Electronic Resource
    The random coin method: Solution of the problem of the simulation of a random function in the plane (1980)
    Springer
    Mathematical geology 12 (1980), S. 25-32 
    Details
    ISSN: 1573-8868
    Keywords: random function ; geostatistics ; simulation ; covariance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract This paper presents a new geostatistical method to obtain realizations of stationary random functions in the plane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01039901
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