电导率线性变化测井二维有限单元法数值模拟  

2 Demention Finite Element Method to Simulate Logging when Conductivity is Piecewise Linear Variable

作　　者：欧东新[1] 阮百尧[2] 王家林[1] 

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]桂林工学院资源与环境工程系,广西桂林541004

出　　处：《同济大学学报（自然科学版）》2005年第5期692-695,共4页Journal of Tongji University:Natural Science

基　　金：国家自然科学基金资助项目(40064001)

摘　　要：以往电测井有限单元法的数值计算中往往假定电导率分块均匀,或者在纵向分段均匀,或者在纵向上不变.为模拟电导率连续变化的情况,提出一种测井二维有限单元数值模拟方法.允许电导率在矩形单元内纵向(井轴)和横向上都可以线性变化,使之能模拟复杂的地电模型.采用异常电位法在变分中消除了电源项这个奇点,使电源附近的电位计算更加精确.此外还考虑了地面的影响,可以对地表附近的测井曲线进行研究分析.经过对多种模型的计算,证明了方法的正确性.In past logging modeling,conductivity is generally assumed homogeneous in each rectangle element or invariable in z direction or piecewise homogeneous in z direction.Considering the effect of ground and in accordance with axial-symmetric resistivity distribution,a 2 demention finite element method(2D FEM) used to simulate logging is put forward in this paper,which uses abnormal potential method so that potential calculated near the current is more accurate.It can be applied when conductivity is piecewise linear variable in z and x directions.Moreover,considering the effect of ground,it can also be applied when current source is close to ground very much.At last some examples are given to testify the method derived in this paper.

关 键 词：测井 有限单元法 电导率线性变化 异常电位法 

分 类 号：P319.1[天文地球—固体地球物理学]