多孔介质渗透率的分形描述

针对土壤、岩石等多孔介质结构的复杂性,从其结构形成的物理机制和达西定律出发,利用分形几何理论,将土壤等作为在统计意义上具有分形特征的多孔介质来研究其水力参数与结构之间的关系,建立了饱和多孔介质渗透率与其分维数之间的定量化的函数式。试验应用扫描电镜法研究了多孔介质断面微结构并算出分维数。试验结果表明:利用该模型预测的多孔介质渗透率与实测值基本吻合,能够比较精确地预测多孔介质水力参数。     

Wave Processes in Inhomogeneous Nonlinear-Dissipative Media

Several problems for nonlinear localized wave processes are analysed. Wave solutions of the kink type, concentrated in the vicinity of some curve l, are considered. Both the solution and the curve l are unknown. It is shown that the determination of l may be realized without knowledge of the solution. For one class of problems, a variational principle for finding l, similar to the Fermat principle, is obtained. Types of waves are found which exist due to the inhomogeneity of the medium or due to the initial front curvature only.     

块石的热扩散系数和导热系数确定方法

采用块石路堤、护坡有利于冻土地区路基的稳定性.基于气温波动条件下块石内部的温度波动幅度按指数规律衰减, 介绍了块石的热扩散系数和导热系数测量方法.实验中, 采用封闭的块石试样筒, 通过顶板温度波动的控制来模拟气温的周期性变化, 整个试样筒用绝热性能良好的海棉包扎, 使其侧向、底板绝热. 对粒径为6～8 cm, 4～6 cm, 2～4 cm的3种块石试样进行了具体测量, 由曲线拟合所得的结果具有较好的一致性.分析显示粒径较小的块石其热扩散系数和导热系数也较小.     

Multiwave Amplitude Compensation and Its Sensitivity Analysis to AVO Inversion in Viscoelastic Media

We derive formulae of correction for multi-wave geometric spreading and absorption in lay-ered viscoelastic media,this provides the theoretical foundation for true amplitude compensation of field data and for our sensitivity analysis.The imaging matrix at a plane reflector between viscoelastic media can be determined in the frequency domain using linearized reflection coefficients through Born approxi-mation.We quantiqatively analyze the sensitivity by studying eigenvalues and eigenvectors of the imaging matrix.The results show that two linear combinations of petrophysical parameters can be determined from the multi-wave AVO inversion in the case of amplitude compensation.Multi-wave AVO contains the information of attenuation in the media.However,the sensitivity of multi-wave AVO inversion to at-tenuation is small.     

Seismic anisotropy of the lithosphere around the Trans-European Suture Zone (TESZ) based on teleseismic body-wave data of the TOR experiment

A passive teleseismic experiment (TOR), traversing the northern part of the Trans-European Suture Zone (TESZ) in Germany, Denmark and Sweden, recorded data for tomography of the upper mantle with a lateral resolution of few tens of kilometers as well as for a detailed study of seismic anisotropy. A joint inversion of teleseismic P-residual spheres and shear-wave splitting parameters allows us to retrieve the 3D orientation of dipping anisotropic structures in different domains of the sub-crustal lithosphere. We distinguish three major domains of different large-scale fabric divided by first-order sutures cutting the whole lithosphere thickness. The Baltic Shield north of the Sorgenfrei–Tornquist Zone (STZ) is characterised by lithosphere thickness around 175 km and the anisotropy is modelled by olivine aggregate of hexagonal symmetry with the high-velocity (ac) foliation plane striking NW–SE and dipping to NE. Southward of the STZ, beneath the Norwegian–Danish Basin, the lithosphere thins abruptly to about 75 km. In this domain, between the STZ and the so-called Caledonian Deformation Front (CDF), the anisotropic structures strike NE–SW and the high-velocity (ac) foliation dips to NW. To the south of the CDF, beneath northern Germany, we observe a heterogeneous lithosphere with variable thickness and anisotropic structures with high velocity dipping predominantly to SW. Most of the anisotropy observed at TOR stations can be explained by a preferred olivine orientation frozen in the sub-crustal lithosphere. Beneath northern Germany, a part of the shear-wave splitting is probably caused by a present-day flow in the asthenosphere.     

注采试井双对数理论图版

注采试井分析以多井渗流力学理论为基础，求解注采井地下渗流的精确解，研究注水井与生产井之间的关系，用注采比、注采井距、注采污染系数比、注采窜流系数比等参数刻画注、采井间关系。在理论上进一步完善地下渗流力学理论，从单井的参数分析发展到井问关系分析，因此也从研究内容上补充了现代试井分析。在建立无穷大地层油水两相双重介质续流污染的注采无量纲模型基础上，对注采无量纲模型求精确解，将其数值反演求实空间解，制作出注采试井双对数理论图版。     

Forward and Inverse Problems in Modeling of Multiphase Flow and Transport Through Porous Media

The paper deals with numerical simulation techniques for forward and inverse modelling in multiphase (multicomponent) flow through porous media. The forward simulation software system MUFTE-UG uses recent discretization techniques and fast solvers. The efficient integration of optimization strategies for the solution of the inverse problems is demonstrated in detail and also applied to practical numerical examples.     

Influence de la microporosité sur le piégeage du gaz dans un milieu poreux naturel

Trapped-gas content in natural porous media, also called residual gas saturation (Sgr), corresponds to the imbibition end-point. To define the parameters controlling Sgr, two parameters were studied: the influence of rock characteristics (on 400 sandstone samples) and initial gas saturation (Sgi), on the basis of 60 experimental curves between Sgr and Sgi. Based on an extensive experimental database, this study establishes the dominant influence of microporosity on trapped gas saturation, and indirectly that of the contained clays. To cite this article: K. Suzanne, J. Billiotte, C. R. Geoscience 336 (2004).     

双相介质中纵波方程的高阶有限差分解法

从双相介质中的纵波方程出发,导出了求解双相各向同性介质中纵波方程的高阶差分格式,给出了吸收边界条件和稳定性条件,在此基础上实现了双相各向同性介质中纵波方程的高阶有限差分法正演模拟,数值模拟结果表明,这种算法能在少量增加计算量的前提下大大提高精度,算法可同时应用于叠前和叠后的数值模拟。