| Relative to the kirchhoff migration which based on ray tracing method, the wave-equation migration theory, especially the reverse-time migration theory, which based on using wave filed extrapolation, can be adapted to any change in the velocity field, and the use a variety information of wave field imaging. So it resolved two problems: large lateral velocity change while structural imaging with high-steep dip.In this dissertation, we discuss the low frequency noise and the wave field influence in pre-stack reverse time migration technique. And study how to solve this problems by imaging technology. In There are two main and both important parts in wave equation prestack migration process: extrapolation and imaging. If accurate extrapolation without good migration can not get a well results, at the same time better imaging condition can be improved computational efficiency and image quality. With the increasing demand for prospecting oil and gas in complex structure and in-depth research, prestack wave equation migration is gradually evolvement from research to production. So the imaging technology for wave equation migration appears more importantce.In this dissertation, we try to use experiment to demonstrates the major part of low-frequency noise what grow out of internal reflection between two strong reflecting surface can not be simple filtered. If this noises are muted before migration will debase the imaging for steep fault. While if filtering them after stack will lose effective amplitude and then hinder amplitude preservation. From the standpoint of information using, the wave equation migration is not only calculated the wave field which at location of the opposite direction of propagation, and it need to use multiple-reflect waves, prism-wave, scattering wave and another wave information to imaging. Useful wave like prism-wave be Filtered through routine, will reduce the availability of reverse time migration.
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