Navegando por Palavras-chave "Multiquadric equations"

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    Determination of volumetric uncertainty for geological bodies detected by boreholes
    (Elsevier B.V., 2015-04-01) Yamamoto, Jorge Kazuo; Kikuda, Antonio Tadashi; Koike, Katsuaki; Cruz Campanha, Ginaldo Ademar da; Baptista Leite, Claudio Benedito [UNIFESP]; Endlen, Arthur; Lopes, Santiago Diaz; Universidade de São Paulo (USP); Kyoto Univ; Universidade Federal de São Paulo (UNIFESP)
    The volume of a mineralized body depends on the information available on borders between mineralization and host rocks. Sometimes, information is limited and a precise determination of the volume of ore body is not possible. This is the situation that a possible solution comes from stochastic simulation. Actually, simulation is carried out on an uncertainty zone in which the contact between ore and host rocks is located. Within the uncertainty zone different ore body shapes can be simulated and their volumes calculated. the frequency distribution of volumes and its statistics give us a good idea about volumetric uncertainty associated with an ore body. in order to avoid using an uncertain model for volumetric simulation, the initial model is resampled and post-processed for uncertainty reduction. This model with reduced uncertainty is then used for volumetric simulation. (C) 2015 Elsevier B.V. All rights reserved.
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    Post-processing of sequential indicator simulation realizations for modeling geologic bodies
    (Springer, 2015-02-01) Yamamoto, Jorge Kazuo; Barbosa Landim, Paulo Milton; Kikuda, Antonio Tadashi; Baptista Leite, Claudio Benedito [UNIFESP]; Lopez, Santiago Diaz; Universidade de São Paulo (USP); Univ Estadual Paulista; Universidade Federal de São Paulo (UNIFESP)
    Sequential indicator simulation realizations contain unavoidable artifacts that are geologically unrealistic. This happens because unlikely types can be drawn randomly from the cumulative distribution and be assigned to a cell in the simulated model. This cell may then be used as previously simulated data when a cell in its neighborhood is visited during a random walk. the sequential process sometimes results in geologically unrealistic realizations. However, different realizations can reveal hidden features. Each realization contains both reliable geological information and noise that is displayed as unlikely types. This paper proposes applying the averaging filter that is commonly used in seismic reflection data to improve the signal to noise ratio. After applying this filter, all L realizations will be condensed into a single geological model that contains certain and uncertain cells. This average model is then exhaustively sampled for the certain cells, and this new sample is used to post-process the uncertain cells to reduce the uncertainty. This resampling and post-processing procedure can be repeated until the final model is considered to be good enough. the proposed method is tested with a model of a dike that crosscuts two sedimentary units. the synthetic geologic model was sampled with 24 drill holes. the results show that the final geological model with reduced uncertainty reproduces very well the sedimentary units and the orientation of the dike as well. the dike shape is not fully reproduced and still presents uncertainties because of lack of neighbor data.