An optimal synthetic aperture method for the creation of directional sensitivity and removal of the airwave effect in MCSEM data

Abstract

This paper introduces a novel approach to the optimal design of the synthetic aperture method for marine controlled source electromagnetic (MCSEM) surveys. We demonstrate that the sensitivity of the MCSEM survey to a specific geological target could be enhanced by selecting the appropriate amplitude and phase coefficients of the corresponding synthetic aperture. We have developed a general optimization technique to find the optimal parameters of the synthetic aperture method. This approach makes it possible to increase the corresponding ratio between total and background fields within the area of an expected reservoir anomaly and in this way improve the resolution of the EM data with respect to potential subsurface targets. We also demonstrate that this optimal synthetic aperture method can be used for a removal of the distorting airwave effect from the MCSEM data collected in shallow water.