起伏地形电阻率剖面异常研究

【作者】 刘杰；

【导师】 席振铢；

【作者基本信息】 中南大学 ， 地球探测与信息技术， 2008， 硕士

【摘要】 长期以来,研究起伏地形条件下的地电异常是电法勘探中一个难题,一方面是由于问题本身比较复杂,另一方面是由于不同时期科技发展水平达不到。众所周知,有限单元法适合于模拟形状不规则的模型,计算精度高,是地球物理数值模拟中较常用的方法。本文主要研究起伏地形条件下的电阻率剖面异常,采用的主要研究手段是应用有限单元法对起伏地形条件下电阻率进行正演模拟。本文首先介绍了研究起伏地形条件下电阻率剖面异常特征的背景和意义,回顾了电法勘探地形影响问题的研究现状。然后介绍了起伏地形条件下有限单元法的计算流程,并对所采用的模拟程序进行了验证。针对山坡、山谷和山脊三种典型地形,进行了多种典型地电模型的电阻率法剖面正演模拟,并对计算出来的结果加以分析,总结了起伏地形情况下的电阻率法剖面异常分布规律,并用经典消除地形影响的方法——比值法,成功地消除了由地形引起的电阻率法剖面假异常。最后总结全文,说明了研究起伏地形条件下电阻率剖面异常对克服起伏地形的影响有一定的实际意义。更多还原

【Abstract】 The research of geoelectric anomaly on the undulate topography has been a difficult problem in the field of electrical prospecting for a long time.As we know, the finite element method suits to simulate models of irregular shape accurately. It is the commonly used method in geophysical numerical simulation. In this paper, we mainly study the anomaly of resistivity section on undulate topography. We use finite element method to study this problem by resistivity forward modeling.In this paper, we firstly introduce the study background and meaning of the problem anomaly of resistivity section on undulate topography. And then we review the study status of terrain effect in electrical exploration. Afterward, the calculation process of the finite element method on undulate topography is introduced. And we have validated the molding programme that we have used. Taking the three typical terrains of brae、valley and ridge as the examples , we have made some forward modeling of resistivity section for many kinds of typical geoelectric models. And we analyze results calculated. The rule of resistivity section anomaly on the condition of undulate topography is summarized. Then we successfully eliminate the artificial anomaly due to terrain effect ofresistivity section by using the typical terrain correction method------ratio method.At the end, we have explained that it is very significative to study this problem of the anomaly of resistivity section on undulate topography, and it is very important to solve terrain effect.更多还原