oa Resolution of Full Waveform Inversion Using Controlled-source Electromagnetic Method

A 3D full waveform inversion is proposed as a processing method in controlled-source electromagnetic (CSEM) exploration. Using synthetic data simulated for a model, we demonstrate that conductive anomalies beneath the surface could be estimated with the proposed method. We discuss the resolution of our CSEM inversion method, considering the orientation of the dipoles of a transmitter and plural receivers. The synthetic inversion results show that the horizontal location of conductivity anomalies would be imaged using horizontal dipoles with high resolution, while the vertical location using vertical dipoles. On the other hand, the degradation of the resolution is observed for the vertical and horizontal locations of conductivity anomalies using horizontal and vertical dipoles, respectively. We then explain that these differences in the resolution of the inversion results are originating from those of secondary electric current. From our numerical results, we conclude that it is efficient to employ dipoles of plural orientations both for transmitter and for receivers to apply our inversion method with the high resolution.