Singular Function Normalization - A Method for a Fast Interpretation of CSEM Data

We describe a new method for a fast interpretation of marine controlled source electromagnetic (CSEM) data based on the approximation of the "Magnitude Versus Off-set" (MVO) signals with singular functions. These functions have been selected since they may be considered a good approximation of the MVO signals relative to the simplest case of the half-space, which is in fact singular at the zero-offset. Being the shape of MVO signals dependent on the local resistivity distribution, the estimated parameters in the exponents of these singular functions can give information about the presence of buried resistive bodies. So, the method allows a preliminary, but fast, definition of the areas where higher values of resistivity occur in the underground, possibly linked to oil or gas reservoir or even to geological structures. The method has been tested on synthetic data and then has been applied in a complex exploration area in the Barents Sea adjacent to an extensive carbonate platform.