非均匀网格剖分的时域有限差分瞬变电磁三维正演

发布时间：2018-02-02 15:42

本文关键词： 瞬变电磁三维正演有限差分法非均匀网格脉宽　出处：《地球物理学进展》2017年03期 　论文类型：期刊论文

【摘要】：将回线源电流密度加入时域麦克斯韦方程组的安培环路定理方程,可以实现任意发射波形的电磁响应三维正演.因为源电流密度参与迭代计算,所以称此法为有源有限差分法.本文采用非均匀网格的有源有限差分算法,对均匀半空间、K型和H型层状模型、三维低阻模型进行了正演计算,验证了算法的有效性和精度;对三维低阻体和高阻体进行正演,分析它们的响应特征规律;对不同脉宽的梯形波响应规律加以研究,并与阶跃波响应理论值进行对比,结果表明脉宽大小对梯形波响应早期影响不大,对响应晚期影响显著,脉宽越小,梯形波响应幅值衰减越快,结果越早偏离阶跃波响应的理论值.
[Abstract]:When the current density of the loop source is added to the Ampere loop theorem equation of the Maxwell equations in time domain, the electromagnetic response of arbitrary transmitting waveform can be obtained by three-dimensional forward modeling, because the source current density participates in the iterative calculation. So this method is called active finite difference method. In this paper, we use the active finite difference algorithm of non-uniform grid to calculate the K-type and H-type layered model and three-dimensional low-resistance model in uniform half-space. The validity and accuracy of the algorithm are verified. The response characteristics of three dimensional low and high resistance bodies are analyzed. The response law of trapezoidal wave with different pulse widths is studied and compared with the theoretical values of step wave response. The results show that the magnitude of pulse width has little effect on the early response of trapezoidal wave, but has a significant effect on the late response, and the smaller the pulse width. The faster the amplitude attenuation of the trapezoid wave response, the earlier the result deviates from the theoretical value of the step wave response.
【作者单位】：中国地质大学(北京)地球物理与信息技术学院;新疆维吾尔自治区地质调查院;中国水利水电科学研究院;中国国土资源航空物探遥感中心;
【基金】：地质调查项目(12120113098800,1212011221115)资助
【分类号】：P631.325
【正文快照】： 1.中国地质大学(北京)地球物理与信息技术学院,北京1000832.新疆维吾尔自治区地质调查院,乌鲁木齐8300003.中国水利水电科学研究院,北京1000384.中国国土资源航空物探遥感中心,北京1000831.School of Geophysics and Information Technology,China University of Geosciences,

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