3-D Controlled Source Electromagnetic (CSEM) interferometry by multi-dimensional deconvolution

Controlled Source Electromagnetic (CSEM) is an important technique in hydrocarbon exploration because it uses the large contrast in electrical resistivity to distinguish between water and hydrocarbons. In a shallow sea environment, the airwave that is refracted from the air-water interface dominates the recorded signal at large offsets. Therefore, the hydrocarbon detection ability of the CSEM is weakened because the airwave is independent of the properties of the subsurface. For a layered earth model, we apply multi-dimensionaldeconvolution interferometry to synthetic 3D CSEM data and estimate the reflection response of the subsurface. The difference in the models with and without a resistive layer is significantly increased by the employed interferometric analysis. However, the required receiver spacing is much denser than that of current CSEM surveys. In order to apply this technique to a field survey, we are currently working on how to relax the required receiver criterion for this technique.