三维MCSEM利用电磁场分解消除空气波效应

Removing airwave effects using electromagnetic fields decomposition for 3D MCSEM

对于浅水域可控源电磁勘探,在资料处理和解释过程中需要消除空气波影响,电磁场上下场分解方法是消除这种影响的一种有效手段.为了快速有效实现电磁场分解,假定电磁场沿水平方向变化缓慢,基于麦克斯韦方程组,本文推导了一种仅利用电磁场水平梯度实现电磁场分解新方法.数值试验表明利用这种分解方法可以得到稳定可靠的分解结果,同时论证了这种方法是一种海洋可控源电磁法(MCSEM)数据快速定性解释手段.

For marine controlled source electromagnetic （MCSEM） prospecting, it＇s necessary for us to remove airwave effects when the data are processed and interpreted, and electromagnetic upgoing and down-going parts decomposition is a kind of effective technology. In order to quickly and efficiently implement such method, supposing that electromagnetic fields vary slowly along horizontal direction, this paper deduced a new method that only uses horizontal gradient of electromagnetic fields to decompose electromagnetic fields based on Maxwell＇s equations. The decomposition effects were verified by MCSEM modeling tests which indicates that we can obtain stable and reliable results using the new method, meanwhile demonstrates that the new method is also a kind of qualitative interpretation technology for MCSEM.