| The migration technology connecting with the ultimate goal of seismic exploration has a direct impact on the final result. In the past, normal migration which usually uses post-stack migration played a very important role in the area with relatively simple structure. However, with the development of seismic exploration, facing to the fact that both the surface and underground structures are more and more complex, it no longer produced the desired effect.The pre-stack migration, particularly the technique based on the wave equation, is one of the effective methods in solving complex structures imaging, which is also the trend of seismic data imaging in home and abroad in recent years. Pre-stack migration is also the key technique in solving seismic data imaging in complex areas where the velocity varies rapidly. In addition, under the condition of fair exact near surface velocity model, pre-stack depth migration from rugged topography directly is an effective method to deal with both the complex surface and the imaging of complex geological structures.The thesis firstly introduces the basic conception of migration and its development history. Then, it studies the conception of depth migration from irregular surfaces with depth extrapolation methods. Since there are other methods, instead of PS, the following part of the thesis introduces four depth migration methods based on one-wave equation and studies how to achieve the pre-stack depth migration from irregular surface directly.Finally, some model tests and conclusions are shown in the rest of the thesis. Through the model test results, we can see that the methods can indeed eliminate the effect of rugged surface on imaging of subsurface geological structures pretty well. They do solve the problem of both complex surface and complex subsurface structures at certain extent. The imaging of both the surface and subsurface has high accuracy. These tests and conclusions provide us new train of thought.
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