Narrow-azimuth migration of marine streamer data

I introduce a new migration method that overcomes the limitations of common-azimuth migration while retaining its computational efficiency for imaging marine streamer data. The method is based on source-receiver downward-continuation of the prestack data with a narrow range of cross-line offsets. To minimize the width of the cross-line offset range, while assuring that all the recorded events are correctly propagated, I define an “optimal” range of cross-line offset dips. To remove the effects of the boundary artifacts I apply a coplanarity condition on the prestack image. This process removes from the image cube the events that are not correctly focused at zero offset. Tests of the proposed method with the SEG-EAGE salt dataset show substantial image improvements in particularly difficult areas of the model and thus confirm the theoretical advantages of the new method over common azimuth migration