3-D pre-stack depth migration for salt and subsalt structures using reverse-VSP data

A 3-D scalar pre-stack reverse-time depth migration algorithm is used to image salt and subsalt structures from synthetic wide-aperture seismic data for sources located in a deviated borehole. The wide effective angular aperture associated with downhole sources allows 3-D imaging of steeply dipping salt flank and subsalt structures that are not usually accessible from surface survey data. Numerical simulation of field experiments allows the imagibility of a target to be tested for any survey geometry, optimization of survey parameters, and testing of processing procedures. The 3-D nature of the recorded wavefield requires full 3-D depth migration; 2-D processing of the data produces unrecognizable images dominated by out-of-plane artifacts. -Authors