有限源瞬变电磁法正演模拟研究

Forward modeling study on TEM based on finite source

针对现有物探工作人员施工效率低、瞬变电磁法资料解释能力有限的问题,以中心回线有限源激发的磁源为例,研究了基于COMSOL MULTIPHYSICS瞬变电磁法不同物理模型的正演过程。并通过对比分析数值解与理论解,验证了使用COMSOL MULTIPHYSICS进行瞬变电磁法正演的可行性。结合模型实例,给出基本建模思路和操作技术,方便快捷地模拟出了低阻球体周围磁场的空间分布规律,分析不同埋深低阻层的归一化感应电动势曲线,并验证了电磁波在地下空间中的传播规律。这为野外矿井生产与工程勘探提供一定的理论指导依据,结合反演理论,有助于方便实时解释异常体的位置和规模。COMSOL MULTIPHYSICS丰富的后处理功能使得结果直观、形象,将为工作人员提供良好的正演环境。

Aimed at the problems of low construction efficiency of geophysical engineers, and limits exist in the interpretation level of the transient electromagnetic method （TEM） , taking magnetic source that excited by central loop as example, forward modeling of TEM based on COMSOL MULTIPHYSICS were carried out on different physical models. By analyzing and comparing numerical result with theoretic value,the feasibility of the forward modeling based on COMSOL MULTIPHYSICS were proved. Taking several models for ex-ample ,the basic ideas of modeling and operation technology were provided, it is convenient to simulate the distribution of magnetic field. Analyzing normalized electromotive force curves of the various low-resistivity layers to verify the propagation laws of electromagnet-ic wave in underground space, which will provide a theoretical guidance for mine production, engineering detection and environmental exploration and be helpful to explain the position and scale of anomalies in time. COMSOL MULTIPHYSICS with multifunctional image processing making intuitive and clear results will provide a good forward environment for engineers.