Numerical Analysis of the Effect of Mesoscale Eddies on Seismic Imaging

The influence of the mesoscale eddy on seismic wave propagation and seismic imaging in deep sea is investigated. Based on fundamental fluid equations, an appropriate partial differential equation is derived for the acoustic pressure field in water with eddies, including current effects. Seismic wavefields and synthetic seismograms in the center of the eddy are simulated. Numerical experiments demonstrate that velocity variations caused by the eddy can lead to traveltime perturbations. Further, in seismic images, the reflectors below the water layer are positioned incorrectly due to the perturbation of the eddy and this image perturbation depends linearly on the migration velocity of the layer below the corresponding reflector. The zero-offset seismic profiling throughout the affected area of the eddy shows that the maximum traveltime perturbation appears at the center of the eddy and the structure of horizontal reflectors below the water layer are distorted.