Removal of the airwave effect by main-part decomposition of the anomalous field of MCSEM data
Wang Shu-Ming1, Di Qing-Yun2, Wang Ruo2, Wang Xue-Mei1, Su Xiao-Lu1, and Wang Peng-Fei1
1. Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, China.
2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
Abstract：
The airwave effect greatly influences the observational data from controlled-source electromagnetic exploration in shallow seas, which obscures the abnormal effects generated by exploration targets and, hence, affects the accuracy of the late exploration data interpretation. In this study, we propose a method to separate the main part from the anomalous field of marine controlled-source electromagnetic method (MCSEM) data based on Stratton–Chu integral transforms to eliminate the airwave effect, which dominates observed electromagnetic (EM) response in shallow seawater. This method of separating the main part from the anomalous field is a type of finite impulse response filter based on a discrete data set. Theoretical analysis proved that the method is stable and able to effectively depress noise. A numerical test indicated that the method could successfully eliminate the airwave effect from the observed EM signals generated by an air–water interface and a seawater layer. This technique is applicable for seawater models with either flat or rough seabeds.
. Removal of the airwave effect by main-part decomposition of the anomalous field of MCSEM data[J]. APPLIED GEOPHYSICS, 2018, 15(1): 3-10.
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