【作者】 肖波；

【导师】 戴前伟；

【作者基本信息】 中南大学 ， 地球探测与信息技术， 2011， 硕士

【摘要】 固定点源激电测深是一种激发极化测深勘探方法。在实际工作中该装置可同时使用多台接受机进行测量,工作效率高；测量电极极距变化灵活,方便省时；供电点位置不同,使得导体极化场位置不同,可更好的确定异常体的位置。因此,固定点源激电测深法已被广泛的应用到了地球物理勘探实际工作中。目前固定点源激电测深在常规的定量解释工作中取得了一定成果,但也存在明显的缺陷和不足。如：该方法只适应较简单的地电条件和模型,对复杂模型总体解释精度不高；受点源位置分布影响大,如果点源位置相对异常体成非对称性分布,异常体的等值线图将会呈现为圆弧形；对组合模型的解释工作中通常会有明显的假异常,导致真实异常体的信息被削弱甚至被掩盖。对此,本文研究了固定点源激电测深最优化反演方法,并将两种解释方法进行了分析对比。论文从有限元正演模拟和最优化反演方法的角度入手,对正演模拟和反演中所涉及的一系列问题进行了系统的研究。研究了起伏地形且电性参数连续分布的有限元模拟方法、起伏地形条件下有限元网格的剖分方法、大型稀疏矩阵的存储方法、大型线性方程组的快速求解方法,以及约束条件下的最小二乘反演方法、偏导数矩阵的计算及加速技术、广义线性反演方程的求解方法。研究并设计了有限单元法正演模拟和最优化反演方法的算法、数据结构及编写了程序。本文对圆弧交汇-相对强度法的计算方法进行了研究,并编写了相应的程序。对多个地电模型实例进行了计算,并把最小二乘反演结果与圆弧交汇-相对强度计算结果做了对比,结果表明,最小二乘反演能适应各种地电模型进行反演,在复杂模型、组合模型以及起伏地形等地电条件下的反演效果优于圆弧交汇-相对强度法计算结果。更多还原

【Abstract】 Fixed point source IP(Induced polarization) is a method of induced polarization geophysical exploration.This method can use several receivers to measure data at the same time,so,this method has high work efficiency.And the measure of electrode distance change is flexible, which make this method is convenient and time-saving.Thirdly,different power point location has different conductor polarization field location, then, we can confirm the position of anomalous body more easily.So,this method of fixed point source shock electricity measure depth has been widely applied to the practical work of geophysical.Currently,the research working of quantitative interpretation by Fixed point source IP has obtained some achievements,but there also exist some obvious deficiency and defects.Such as,this method just adapt to some simple terrestrial electricity condition and models,And,affected by the position distribution of point sources greatly,if the position distribution of point sources do not symmetrical from the abnormal body,the isoline of abnormal body will be performance for arc shape.Thirdly,it will cause obvious fake anomaly when we explaining for the combination models,which can cover the information of the real abnormal bodys.To this,this paper studied the optimization inversion method,and then the two methods of interpretation was analyzed and compared.This thesis studied a series of problems which related to the calculation of the finite element forward modeling and the optimization inversion method,which include the finite element forward modeling method base on the undulate topography and the electrical parameters of abnormal body continuous change,and the studied the method of finite element mesh dissection under the condition of undulate topography.This thesis also studied the storage method of large sparse matrix and the fast solving method of large linear equations,the least-square inversion method under constraint condition and the calculation and accelerating technology of partial derivative matrix.And the solving method of generalized linear inversion equation.And then,this thesis research and design algorithm and data structure of finite element method forward modeling and optimum inversion method algorithm,and write the programs.This article studied the calculating method of the arc intersect-relative strength method and wrote the program.Then make some of the terrestrial electricity models as examples,and compared the least-square inversion results to arc intersection-relative strength calculation results.The result shows that the least-square inversion method can adapt to all of the terrestrial electricity models.The calculate results of inversion are better than the arc intersect-relative intensity method in the complex model,the combination model and undulate topography terrestrial electricity conditions.更多还原