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21.
目前,阵列声波测井信号处理大多在时间域或频率域中进行。但是,单纯的时间域或频率域方法有很大的局限性。为了打破这些局限性,笔者将分数阶Fourier变换方法用于阵列声波测井信号的分析之中,研究了不同性质储集层中信号幅度随分数阶Fourier变换阶数变化的规律。实验结果表明:在干层,幅度呈"1"型分布;在水层,幅度呈"Y"型分布,"Y"的两支开口较小,在阶数大于0.3的区域中,幅度较大;在油层,幅度呈"Y"型分布,"Y"的两支开口较大,在阶数大于0.6的区域中,幅度较大。因此,分数阶Fourier变换在提取阵列声波测井蕴含的储集层流体性质信息方面具有很好的前景。 相似文献
22.
二维饱和多孔介质因点汇诱发比奥固结的解析解 总被引:1,自引:0,他引:1
给出了有限二维饱和多孔介质因点汇诱发的Biot固结的一个解析解。其中假设多孔介质为均匀各向同性和线弹性,假设孔隙压力场符合第1类边界条件,数学模型采用可压缩多孔介质模型。利用傅里叶和拉普拉斯变换及相应反演获得了双重无穷项级数和形式的精确解。然后特别探讨了定流量点汇诱发的稳态解析解,并用文献现有解析解进行了验证。所提出的解析解适合于验证数值解,并可用于深入分析有限二维多孔介质的流-固耦合行为。 相似文献
23.
J. Aitchison 《Mathematical Geology》1990,22(4):487-511
In recognizing that a composition, such as a major oxide or sediment composition, provides information only about the relative, not the absolute, magnitudes of its components, this paper exposes the compositional variation array as the simplest and minimum way of summarizing the pattern of variability within a compositional data set. Such summaries are free of the notorious hazards of the constant-sum constraint and when depicted in relative variation diagrams can often provide substantial insights into the nature of the compositional variability. Concepts and practice are illustrated by reference to a number of real data sets. 相似文献
24.
Mediterranean flash flood transfer through karstic area 总被引:1,自引:0,他引:1
Vincent Bailly-Comte Hervé Jourde Axel Roesch Séverin Pistre 《Environmental Geology》2008,54(3):605-614
Karstic aquifers influence flash floods propagation in Mediterranean countries. Near Montpellier, Southern France, discharge
data are recorded on the Coulazou River upstream and downstream of the Aumelas Causse. Two gauging stations are used to describe
the hydrodynamics of this binary karstic system. The first station characterizes the non-karstic catchment area. The second
one is representative of the karstic part of the watershed. Records since April 2004 are used to understand how the river
interacts with a karstic aquifer. Hydrograph analysis of three flash flood events is described. Corresponding discharge time
series recorded at the two gauging stations are used to describe the modification of the hydrographs by auto- and crosscorrelations
analyses. Finally, linear system analyses are used to provide the transfer functions of this binary karstic system according
to the three flood events characteristics (initial conditions, volume, spatial distribution of rainfall, etc.). Theses functions
summarize the hydrodynamic behaviour of the system: their shapes are indicative of the dynamics of the storage, the release
and the contribution to surface waters.
相似文献
Vincent Bailly-ComteEmail: |
25.
The use of wavelet transforms is explored to investigate the nonlinear dynamical characteristics of ship roll and coupled heave-roll motion. The harmonic character, double period character and chaotic character are observed via a time–frequency window of the wavelet transform. Typical wave parameters in different stability regions are considered. Features such as restoring rolling, divergence rolling, steady state and chaotic responses of ship roll are obtained as well. The investigation in this paper not only highlights the feasibility of using wavelet transforms in the analysis of nonlinear dynamic characteristics of ship rolling in waves, but also shows how it could enhance the analysis abilities. 相似文献
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28.
Formulae for the Keplerian expansions in terms of Henrard's practical variables are given. Two different methods were applied: one using the Bessel functions and one based on the Lie transforms. The former involves less series products, but the latter is more flexible and universal. 相似文献
29.
30.
Eigenvalue approach, following Laplace and Fourier transforms, has been employed to find the general solution to the field
equations in an anisotropic liquid-saturated porous medium, in the transformed domain. The results of isotropic liquid-saturated
porous medium can be derived as a special case. A numerical inversion technique has been applied to get the solutions in the
physical domain. To illustrate the utility of the approach, an application of infinite space with impulsive force at the origin
has been considered. The results in the form of displacement and stress components have been obtained and discussed graphically
for a particular model. 相似文献