共查询到20条相似文献,搜索用时 31 毫秒
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讨论了应用Koefoed法自动直接解释电测深曲线中的数据采集、归化采样值的计算、反演计算、正演计算、图形显示以及计算精度等问题,并介绍了由作者开发的一套完整的电测深自动解释软件。 相似文献
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本文在大地电磁测深松弛(rapid)反演理论方法的基础上,探讨了电偶源频率电磁测深(赤道装置)阻抗视电阻率的二维反演问题。由二维层状模型反演目标函数的近似简化出发。将全剖面的二维反演约化为沿剖面各测点的逐一测点一维反演,从而构制了一个简易可行的二维层状模型参数化反演方案。反演试验表明,这一反演方法是实用和有效的 相似文献
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V.V. Plotkin 《Russian Geology and Geophysics》2018,59(3):324-333
The paper presents the results of a joint inversion of magnetotelluric sounding (MTS) curves taken at several stations without preliminary selection and normalization and distorted by the presence of lateral electrical-conductivity inhomogeneities in the medium. In the calculations, we used synthetic MTS data for a three-dimensional model. Preparation and interpretation of data are carried out by the Trefftz method using a numerical model of the field and MTS curve distortions. To solve the inverse problem and optimize the subsurface model, we used a nonlinear least-squares method and an iterative process with calculation of the sensitivity matrix and its singular decomposition. The target functional is determined by the discrepancies between the model and synthetic experimental apparent-resistivity curves corresponding to the elements of the impedance tensors on the lateral diagonal. The reliability of the reconstructed subsurface model is characterized by the dispersion of the deviations of its parameters from the parameters of the known model used for the preparation of synthetic experimental data. The joint consideration of distorted apparent-resistivity curves at several stations increases the reliability of interpretation results. The obtained solution to the inverse problem is approximate and can be used as a starting model for more complex algorithms and programs. 相似文献
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张秋瑞 《华北地质矿产杂志》1998,13(3):276-284
本文以垂直磁偶极子发射,接地导线测量这样一种发一收装置为例,讨论了求解时间减电磁场问题的计算方法,具体思路是:用线性滤波法,先求解频率域问题,然后且Gaver-Stehfest逆拉氏变换法将频率测深正演问题转化为相对应瞬变测深(时间域)正演问题,得到了垂直磁极子场中,水平层状介质表面瞬变电磁场分量的近似表达式,由此计算了视电阻率曲线,并从理论上探讨了瞬变测深视电阻率曲线的垂向分辨能力,本文试图对中 相似文献
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本文根据在电导率随深度变化梯度不大的情况下,DarZarrouk曲线与视电阻率曲线基本重合这一性质,通过各种变换,在电阻率测深中导出了一种可与大地电磁测深中Bo-stick反演方法相比美的直接反演方法,将视电阻率随极距变化曲线转换为电阻率随深度变化曲线。 相似文献
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Ákos Gyulai Mátyás Krisztián Baracza Norbert Péter Szabó 《Environmental Earth Sciences》2014,71(1):383-392
Geophysical surveying methods are of great importance in environmental exploration. Inversion-based data processing methods are applied for the determination of geometrical and physical parameters of the target model. The use of this geoelectric inversion method is advantageous in environmental research where highly reliable information with large spatial resolution is required. The 2D combined geoelectric inversion (CGI) method performs more accurate parameter estimation than conventional 1D single inversion methods by efficiently decreasing the number of unknowns of the inverse problem (single means that data sets of individual vertical electric sounding stations are inverted separately). The quality improvement in parameter space is demonstrated by comparing the traditional 1D inversion procedure with a 2D series expansion-based inversion technique. The CGI method was further developed by weighting individual direct current geoelectric data sets automatically in order to improve inversion results. The new algorithm was named combined geoelectric weighted inversion, which extracts the solution by a special weighted least squares technique. It is shown that the new inversion methodology is applicable to resolve near-surface structures such as rapidly varying layer boundaries, laterally inhomogeneous formations and pinch-outs. 相似文献
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Haby S. Mohamed Mahmoud M. Senosy Gamal Z. Abdel Aal 《Arabian Journal of Geosciences》2014,7(10):4059-4077
The present study is an attempt to upgrade the previously used semi-analytical inverse slope method. The upgrade method was applied to the interpretation of VES’s measured with different electrode arrays in two and three layers laboratory tank model. Then the method was applied on VES’s measured at different sites of different geologic conditions. The study showed that the inverse slope method is a quick method for obtaining depths to interfaces. The method can be implemented on a hand-held calculator or more efficiently on a small microcomputer where the data can be processed at a faster rate than that of conventional data acquisition systems. This allows the method to be potent tools for infield data analysis and more cost effective to assess the success of a sounding on-the-spot and modify the experimental set-up as appropriate. The comparison between the results obtained from this method and the traditional digital computerized methods indicated that the geoelectrical models derived from inverse slope method have a good correlation with the actual model. Also, when applying the method on VES’s measured by using Schlumberger and Wenner arrays at areas of different geologic setting, gave results in comfortable with the actual lithology obtained from the lithologic data of the neighboring wells. The results obtained from the lab experiment and field survey indicated that the inverse slope method has the potential to be applied on VES data collected with any electrode array, the advantage that is not available with all the traditional interpretation methods available nowadays. 相似文献
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电偶源瞬变电磁测深一维全区视电阻率解释方法研究 总被引:4,自引:0,他引:4
本文从理论计算和野外实测资料处理两方面讨论了电偶源瞬变电磁测深─维全区视电阻率解释方法以及与之相关的实测数据预处理、磁场计算及─维磁场数值反演方法. 相似文献
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《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》1999,24(3):215-220
Whenever data sampling is regular along a coordinate in space and/or time, it is relevant to look for approximate shift invariance which casts the forward problem into a convolution formulation. The resulting computations may be speeded up significantly through the Fourier transform. For nonlinear problems the Born approximation in horizontally stratified media leads to just such a result.In many cases the noise is well approximated by a stationary process, and it turns out that the resulting inverse solution is then a multi-channel deconvolution. This formulation allows very fast inversion in the periodic approximation of densely sampled high volume data sets.New applications within geophysical well logging, continuous geoelectrical sounding/profiling, and 3D helioseismic tomography demonstrate the wide applicability of this method. 相似文献
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电偶源瞬变电磁测深一维全区视电阻率解释方法研究 总被引:4,自引:1,他引:4
本文从理论计算和野外实测资料处理两方面讨论了电偶源瞬变电磁测深─维全区视电阻率解释方法以及与之相关的实测数据预处理、磁场计算及─维磁场数值反演方法。 相似文献
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山西某矿位于构造堆积盆地,属黄土匠陵地貌,区内被第四系黄土覆盖,为解决该矿地质构造及水文地质问题,采用三维地震勘探与瞬变电磁法、直流电测深法相结合的勘探方案。利用三维地震勘探解决目的层赋存形态及其地质构造问题,再利用瞬变电磁法进行平面控制,以使平面及深度解释误差达到勘探要求;应用直流电测深法及瞬变电磁进行勘探,在正反演解释的基础上对其资料综合分析、对比,并结合三维地震资料,确定地质构造的富水及导水性。 相似文献
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本文对应用Koefoed法自动直接解释电测深曲线中的数据采集、归他采样值的计算、反演计算、正演计算、图象处理以及计算精度等问题作了讨论.研制了一套完整的电测深自动解释软件. 相似文献
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井中声波CT技术系统及其应用 总被引:1,自引:0,他引:1
叙述了井中声波CT技术系统的测量方式、数据采集和数据预处理以及CT正反演的基本方法, 列举了在工程勘察和油气田开发中的应用实例,显示出井中声波CT成果为查明目标体的位置和圈定目标体的形态是有效的。同时也显示了井中声波CT技术作为一种精细勘查手段,具有开发潜力和应用前景。 相似文献
16.
Comparing the Gradual Deformation with the Probability Perturbation Method for Solving Inverse Problems 总被引:1,自引:0,他引:1
Jef Caers 《Mathematical Geology》2007,39(1):27-52
Inverse problems are ubiquitous in the Earth Sciences. Many such problems are ill-posed in the sense that multiple solutions
can be found that match the data to be inverted. To impose restrictions on these solutions, a prior distribution of the model
parameters is required. In a spatial context this prior model can be as simple as a Multi-Gaussian law with prior covariance
matrix, or could come in the form of a complex training image describing the prior statistics of the model parameters. In
this paper, two methods for generating inverse solutions constrained to such prior model are compared. The gradual deformation
method treats the problem of finding inverse solution as an optimization problem. Using a perturbation mechanism, the gradual
deformation method searches (optimizes) in the prior model space for those solutions that match the data to be inverted. The
perturbation mechanism guarantees that the prior model statistics are honored. However, it is shown with a simple example
that this perturbation method does not necessarily draw accurately samples from a given posterior distribution when the inverse
problem is framed within a Bayesian context. On the other hand, the probability perturbation method approaches the inverse
problem as a data integration problem. This method explicitly deals with the problem of combining prior probabilities with
pre-posterior probabilities derived from the data. It is shown that the sampling properties of the probability perturbation
method approach the accuracy of well-known Markov chain Monte Carlo samplers such as the rejection sampler. The paper uses
simple examples to illustrate the clear differences between these two methods 相似文献
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Electromagnetic sounding of the Kola Peninsula with a powerful extremely low frequency source 总被引:1,自引:0,他引:1
Velikhov E. P. Grigoriev V. F. Zhdanov M. S. Korotayev S. M. Kruglyakov M. S. Orekhova D. A. Popova I. V. Tereschenko E. D. Schors Y. G. 《Doklady Earth Sciences》2011,438(1):711-716
Experiment on electromagnetic sounding of the Kola Peninsula using unique mobile measuring complex of the low-frequency sounding
was conducted, allowing to investigate a geoelectric section with a depth of several kilometers on distances up to 100 km
from the stationary transmitting aerial. Excess on the order of amplitudes of the vertical component above the horizontal
at all frequencies of sounding was registered in a number of points of measurements. This feature managed to be explained
quantitatively by circulation of current on regional faults with the closure of current through the sea—before unknown galvanic
coastal effect. Interpretation of the results of modeling and neural network solving of inverse problem essentially specifies
the fault tectonics of the central part of the Kola Peninsula. Anomaly remote from the observation profile was found out—local
pinch of a crustal conductive layer consisting of graphitized rocks and associated with the zone of overthrust. 相似文献
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