CSAMT一维正演可视化设计与激发极化效应
Visualization design of 1D CSAMT forward modeling and research on the induced polarization effect
-
摘要: 针对可控源音频大地电磁法(CSAMT)开发了一套CSAMT一维数据正演可视化软件。其界面友好,操作简单;使用MATLAB进行核心算法的编写,正演计算过程引入线性滤波系数对汉克尔积分进行求解,并对不同线性滤波系数方案的精度进行了比较;基于Java语言进行操作界面设计,提供多参数设置界面,自动化程度高;通过软件自带的绘图功能,将数据处理结果直观地提供给用户。在计算过程中引入Cole-Cole模型参数,以复电阻率代替不考虑地电体极化效应的直流电阻率,对CSAMT场源一维层状激化介质模型进行了正演模拟,讨论了极化层分别位于不同深度时一维层状介质的极化效应。研究发现极化层埋藏越浅,极化效应对于CSAMT的影响频带越宽。这对于认识含极化效应的CSAMT方法的电磁响应特征,提高数据处理便利度与工作效率方面都具有重要的作用。Abstract: This study developed a piece of visualization software of the 1D data forward modeling applicable to the controlled source audio-frequency magnetotellurics (CSAMT). This software has the advantages of friendly interfaces and simple operations. In detail, MATLAB was used to develop the core algorithms, and linear filter coefficients were introduced to solve Hankel integral in the process of forward modeling. Meanwhile, the accuracy of schemes using different linear filter coefficients was compared. The operation interfaces were designed using Java, and multi-parameter setting interfaces with a high automation degree are available. Moreover, the data processing results can be intuitively provided to users using the drawing function of the software. In the calculation process, Cole-Cole model parameters were introduced, and complex resistivity was used to replace the DC resistivity without considering the polarization effect of geoelectric bodies. Furthermore, this study carried out the forward simulation of CSAMT field source on a one-dimensional layered model of induced polarization (IP) media and discussed the IP effect of one-dimensional layered media with polarization layers at different burial depths. It was found that the frequency band of CSAMT affected by the IP effect widened with a decrease in the burial depth of polarization layers. This result is crucial to understanding the electromagnetic response characteristics of the CSAMT method with IP effect and improving the convenience and efficiency of data processing.
下载: