A towed EM system for hydrocarbon exploration tested on a gas discovery in the North Sea

A newly developed towed EM system has been tested offshore in the North Sea. In this paper we use modeling and inversion to investigate the ability of the towed EM system to detect and characterize a shallow gas discovery. We show that the measured electric field data are of sufficient quality and signal-to-noise ratio for successful detection and inversion of the high resistivity reservoir area including distinction of some of the shallow gas accumulations above the reservoir. 1D inversion in the frequency domain has been performed on individual common mid points (cmps) along a survey line across the reservoir with robust results. The estimated model from the 1D inversion outside the reservoir is used as the 1D background model in 3D modeling. The imposed 3D resistivity model is based on seismic data and interpreted horizons.