Processing of Three Dimension Vertical Cable Data over SEG/EAGE Physical Model

摘要

A physical model similar to the SEG/EAGE numerical salt model was constructed to study the problems and issues of acquiring and processing seismic data over geological situations involving salt and subsalt layers. A large 3D dataset acquired simulating vertical cable is composed of 8 swaths with 8 cables with 8 transducers in each cable to produce truly 3D Common Cable Gathers (CCG) that were processed through pre-stack depth migration. The final image is composed of the stack of all CCG migrated including both upcoming and down-going wave fields. Partial images obtained from stack of depth volumes of each field separately show that down-going field data had reflections with more continuity and higher S/N ratio than the up-coming waves in parts with non-steep dips. The up-coming, however, did a better job in the flanks of the salt. Separation of the up-coming and down-going fields to different datasets for separated migration did not result much difference in the final image. The general results have been showing that vertical cable technique is an excellent tool to obtain depth image of complex geologic structures. The power of stacking migrated images of different hydrophones and cables with different illuminations increase tremendously the signal-to-noise ratio of the depth image resulting in a more reliable information of the subsurface.