十五.计算地球物理
(负责人：杨文采 徐果明 陈晓非)
Computational Geophysics
(Conveners: YANG Wencai XU Guoming CHEN Xiaofei)
1. 高频电磁波测井资料反演的优选调参子空间方法
张美玲 邢光龙
刘曼芬 杨善德
(吉林大学物理系,吉林省长春市,130023)
An Optimum Choice Method
of Adjusted Inversion Parameters'
Sub-space on High Frequency
Electromagnetic Wave Logging Inversion
Zhang M. L. Xing G. L. etal.
(Jinlin University ,Changchun 130023,China)
Abstract
Although the linearity inversion methods have the advantages that their solution's computation time is less and the convergent speed is rapid in some degree, some problems on unsteadiness and multi-solution become more serious in their inversion courses. We think this is a good way that converts the high-dimension search into multi-time low-dimension searches, and the low-dimension search direction of each time is a good search direction. This paper proposes a new method that is called An Optimum Choice Method of Adjusted Inversion Parameters' Sub-space. The method is an attempt in the aspect. It is beneficial to overcome the multi-solution's problems and save a deal of computation time and store space. The good effect has been obtained when it is used into the inversion problem of High Frequency Electromagnetic Wave logging.
Key words: Optimum Choice Method of Adjusted Inversion Parameters' Sub-space, Inversion of High Frequency Electromagnetic Wave Logging.
2. 改进的阻尼型高斯—牛顿法及其对高频电磁波
测井资料的反演
张美玲 邢光龙 刘曼芬 杨善德
（吉林大学物理系，吉林省长春市，130023）
An Improved Damping Gauss-Newton Method and Its Application on the Inversion of High Frequency Electromagnetic Wave Logging
Zhang M. L. Xing G. L. etal.
(Dep. Of Physics, Jinlin University , ChangChun 130023,P R China)
Abstract
Gauss-Newton optimization technique is a method with less computation time and rapid convergence speed. But it requires better initial condition ， it loses its role easily or dips into the area of part-extreme values . This paper proposes a kind of raise damp-form on Gauss-Newton optimization technique to overcome these problems. By leading into the diagonal damping matrix , the damping role will be changed on the relative modified amounts of the inversion parameters. The good effect has been obtained when it is used into the inversion problem of High Frequency Electromagnetic Wave logging. This method is beneficial to the formation parameters' concordant improvement. And the inversion convergent speed and the inversion parameters' preciseness have been improved remarkably.
Key words : Gauss-Newton method 、Damping Matrix 、 Inversion of High Frequency Electromagnetic Wave Logging.
3. 套管井非轴对称声场三维应力—速度有限差分数值模拟
刘继生 马 俊 王克协
谢荣华 曾桂红
(吉林大学 长春 130023) (大庆生产测井研究所 大庆 163153)
Simulation of the non-axisymmetric acoustic fields
in cased holes by 3D SV—FD method
Liu Jisheng, Ma Jun ,Wang Kexie (Jilin University, Changchun, 130023)
Xie Ronghua, Zeng Guihong (Daqing Production Logging Institute,Daqing,163153)
The cased borehole is non-axisymmetric when the cement do not entirely cover the pipe circumferentially. In this paper a 3D variable grid stress-velocity finite difference method is proposed to simulate the cased-hole acoustic field. We discussed algorithm stability, dispersion due to net partition, treatment for inner boundary, field on the axial axis and adsorption boundary conditions. Casing wave excitation and propagation characteristics are analyzed under conditions for tool eccentration or partial cement coverage.
4. 基于二维小波多尺度分析的重力异常分解及应用
张大力1) 何向晨2) 刘家琦1) 侯遵泽3)
1) 哈尔滨工业大学数学系 哈尔滨
2) 北京遥感设备研究所 北京 100854
3) 中国人民武装警察部队学院 廊坊 065000
The
Decomposition of Gravity Anomalies Using Two-dimensional Wavelet Transform and
Multiple Scale Analysis And Its Application
Zhang Dali1) He Xiangchen2) Liu Jiaqi1) Huo Zunze3)
1) Dept. of Math. , Harbin Institute of Technology, Harbin 150001, P.R.China
2) Beijing Research Institute of Remote Sensing Facilities, Beijing 100854, P.R.China
3) Chinese People's Armed Police Force Academy, Langfang 065000, P.R.China
Abstract: A method of two-dimensional wavelet transform and multiple scale are studied and applied to decompose gravity anomalies in this paper. The result of numerical simulation and practical data processing in the Eerduozi Region has shown that the low-order particulars of the wavelet transform mainly correspond to the shallow geology, the higher-order particulars correspond to the structures of both up and middle crust, and the higher-order approaches of the wavelet transform reflect the general tendency of the regional gravity. The method in this paper provides a new way to get local gravity anomalies.
5. 非线性地声学与声测井理论研究初步
王克协
(吉林大学 长春 130023)
Preliminary theoretical Study of Nonlinear
Geoacoustics
and Acoustic Logging
Wang
Kexie
(Jilin University Changchun, 130023 China)
Necessity and reality of studying nonlinear wave dynamics in
geoacoustics and acoustic logging at present are discussed. The experiments
demonstrate that acoustic waveforms recorded in a borehole provide evidence of
mechanical damage in surrounding rock caused by stress concentrations or
drilling, which lead to velocity change of 10% and bright-spots of amplitude.
They are related to nonlinear effects of formation deformation. Nonlinear
dynamical field equations in solid are summarized and borehole problem,
especially prestress prediction by cross dipole acoustic logging, is focused.
Yao Gui-jin Wang Ke-xie
(Jilin University Changchun 130023)
Impedance and thickness of one-layered medium between
casing pipe and formation are selected as two inversion parameters. Linear
least square inversion method with trigonometric function form of phase-shift
and linear least square method with arc-trigonometric function form of
phase-shift are obtained respectively. Investigation of error functions and
inversion results of synthesize data is given. It is found that error functions
of inversion method with trigonometric function form of phase-shift have
multi-minimal points and error functions of inversion method with arc-trigonometric
function form of phase-shift only have one minimum value corresponding to true
value of impedance and thickness. Inversion method with arc-trigonometric
function form of phase-shift is better than inversion method with trigonometric
function form of phase-shift.
.7. 复杂地质结构条件下的三维建模和射线追踪
中国科学技术大学 地球和空间科学系 安徽 合肥 230026
徐果明 徐 涛 李迎春 高尔根
3-D Modeling in Complex Geological Structure and Ray Tracing
XU Guoming, XU Tao et al.
3-D Modeling in Complex Geological Structure and Ray Tracing
XU Guoming XU Tao et al.
Abstract
A new 3-D modeling method is discussed here. We use body→block→interface→element→edge→point→coordinate structure to describe a geological body. This is completely different to traditional layering structure method. Bezier curved interface is used to describe the elements in the model. We use C++ language to realize the software and complete a series of complex geological structures. We introduce a new method - iteration ray tracing method to realize ray tracing in complex body. Using this method the initial transmission points and reflection points are revised by first order correction. The corrections converge very fast. The efficiency is especially high in 3-D ray tracing.
8.
Seismic wavelet estimation via hybrid chaos optimization algorithm
Yin
Cheng Zhao Zhiwei Zhou Dingyong
(Southwest
Petroleum Institute，Sichuan Nanchong 637001)
Abstract: A hybrid chaos optimization algorithm is proposed by the use of the
properties of ergodicity, stochastic property, and regularity of chaos, and
quickly searching characteristics of mating operation of genetic algorithm，and local optimization
operation. Through model testing of seismic wavelet estimation, the result
shows the method is more efficient and convenient than single stochastic
optimization algorithm.
9. The arbitrary difference precise integration
method of solving seismic wave equation
Jia Xiaofeng1,
Wang Runqiu2, and Hu Tianyue1
1 Department of Geophysics, Peking University, Beijing 100871, China
2 Department of Geosciences, University of Petroleum, Beijing 102200, China
Abstract
Wave equation migration is often applied to solve seismic imaging problems. Usually, the finite difference method is used to obtain the numerical solution of the wave equation. In this paper, the arbitrary difference precise integration method (ADPIM) is discussed and would be applied in the seismic migration. ADPIM has its own distinctive idea. When discretizing coordinates in space domain, it employs a relatively unrestrained form in stead of the one used by the conventional finite difference method. Moreover, in time domain it adopts the way of subdomain precise integration method. As a result, it not only takes the merits of high precision and narrow bandwidth, but also can process various boundary conditions and describe the feature of inhomogeneous medium better. Numerical results show the benefit of the presented algorithm of using ADPIM.
10.Boundary Elemant Method apply to typical
cracks
structure
Liu Qiliang Li Shiyu et.al.
Institute of Geophysics, CSB
Abstract
Studies on two typical faults system with
numerical simulating method are presented.
For the first time, the computation of Stress
Intensity Factors (SIF) and stress tensors by global
crack-line displacement fitting is introduced,
improving the accuracy of calculation. Using Boundary
Element Method to obtain Crack Opening Displacement
(COD) data, then using global crack-line displacement
fitting to obtain SIF and stress tensors. This method
is less post processing, more reliable, less time
consuming and easy to put into practice. It can be
applied to mixed mode arbitrary crack problems. The
method is tested and verified in this paper.
The application of the method to two typical cases
of two-dimensional two equal length cracks is
described in this paper. The first one is about two
dimensional collinear shear cracks, mainly discussing
the interaction between the cracks under loading. The
quantitative relationships between the SIF at the tip
and the ratio of the distance between two cracks to
the length of the cracks are presented. Meanwhile, the
stress distributions corresponding to several
geometrical shapes of the cracks are also presented,
with discussion of what conditions can easily make the
cracks break.
The second one is about two dimensional two
parallel shear cracks. In this case, the interaction
between two cracks depends not only on the ratio of
tangential distance between two cracks to the length
of cracks but also on the ratio of normal distance
between two cracks to the length of the cracks.
Quantitatively, the relationships between SIF
distribution and the different combinations of
vertical distance and horizontal distance are
presented. On the other hand, the stress distributions
under several special geometrical conditions are
discussed, describing how the interaction between
cracks affects the crack breaking. Experimental
results are introduced as the qualitative
verification.
11.时间域电磁场的二维有限单元算法
孟永良 王华军
（中国地质大学，武汉，430074）
2-Dimension
Finite element method Algorithm for Time domain Eelectromagnetic Field
Meng Yongliang Wang Huajun
（China University of Geosciences, Wuhan, 430074）
A 2-D finite element method for time domain electromagnitc field, which has 3-D field source, is discussed in this paper. The algorithm includes two parts: total field and second field. Second field algorithm can suitable for various field sources. Uses optimized approach, this algorithm can accelerate calculate speed and gain high accurate solution.
12. 双相介质中弹性波传播的有限元法特征模拟
江 涛 顾汉明 詹正彬
中国地质大学地球物理系 430074
According to Biot’s theory of elastic wave propagation in a fluid-saturated porous solid, the numerical solutions of the finite-element equations have been given in the time domain. Based on numerical modeling, we observed four waves, namely fast and slow compressional waves, fast and slow shear waves. These waves occur reflect and transmission in the double horizon of the geological model and we can see clearly multi-conversion waves.
Key words: two-phase media finite-element method numerical modeling