Detection, Delineation and Characterization of Shallow Anomalies Using Dual Sensor Seismic and Towed Streamer EM data

Recent developments in broadband marine seismic and EM technology enables high-resolution imaging and improved characterisation of shallow anomalies. In particular, broad-band dual sensor seismic data enables separated wavefield imaging that produces high resolution images of the shallow sub-surface even when a wide 3D seismic spread is employed in shallow water. In addition, by using the full wavefield in, for example, full waveform inversion, shallow velocity variations associated with channels, pock-marks and gas-pockets can be imaged. By using a Towed Streamer EM system it is now possible to acquire Controlled Source Electromagnetic (CSEM) data simultaneously with seismic data using a single vessel. CSEM data enables the sub-surface resistivity to be determined, and the simultaneous acquisition enables CSEM data to be acquired efficiently, cost-effectively and early in the exploration cycle. By combining the high-resolution structural and velocity seismic images with images of sub-surface resistivity, it is possible to determine the origin, potential drilling hazard, and resource potential of shallow anomalies.