Abstract：Transient electromagnetic (TEM) method in shallow water has drawn more and more attention in recent years, since it can identify thin resistive reservoirs in shallow water, and separate ocean bottom response from airwave. In this paper, we discuss TEM response in anisotropy layered media in shallow water. First, electromagnetic response in the frequency domain is obtained with TM and TE wave decomposition based on transmission line theory and dyadic Green function theory. Then using the sine and cosine digital filtering algorithm, we obtain the TEM response in anisotropic layered media in shallow water, and compare our results with open source code Dipole1D to verify the accuracy of the proposed algorithm. The following observations are obtained based on numerical tests results: 1TEM response in shallow water is predominantly sensitive to vertical resistivity, not to horizontal resistivity when they are thin and high-resistive reservoirs; TEM response is sensitive to both horizontal and vertical resistivity of overburden on top of reservoirs. 2In shallow water, impulse response curve can separate airwave response from stratum response; step response curves show some anomalies, but cannot separate airwave response from stratum response; in the middle-deep water, airwave and stratum responses are mixed, only some anomalies are showed in impulse and step responses. 3TEM response is sensitive to the thickness of overburdens and reservoirs; with the thickness increase, the anomaly response decreases, but a smaller reservoir thickness can still has anomaly. 4When distance between a reservoir and the basement is small, the basement will significantly reduce the anomaly response from reservoirs; when the distance is more than 1000m, the impact of the basement maybe ignored, because the basement will cause very little change of the anomaly.
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