The Study And Application Of Tomographic Inversion Static Correction

Seismic exploration has become one of the most important technology in the area of exploring petroleum。It play vital function in exploring of the south foothill。Because of complex the earth's surface and subsurface structure, there are a lot of difficulty in the other area. Static correction, eliminating perstack noise,migration are three critical technology. Especially static correction, it is first task in processing seismic data. The effect of static correction not only influence post-process but also decide the final effect of imaging.In seismic data processing, static correction problems do not exist in isolation, It directly affects the efficiency of other processing steps, such as noise removal and velocity analysis. With the terrain of seismic exploration is expand from simple to complex, for 2D to 3D, which call higher request on the static correction method. Upon the conditions of conventional static correction method, we usually assume that layer occurs as horizontal bed, the velocity of surface layer slow-varying, section can be scaled to a chosen planar measurement level with kinematic. But, there are large relief degrees surface and large variable lateral velocity in complex area, which cause difficulties for static correction. The Refraction Statics is on the basis of refracted wave theory, it is very difficulty to find one stably refracting layer in complex areas. So the refraction statics method is unfit these areas. However tomographic inversion static correct on the base of geometric ray theory and wave equation continuation static correct on base of wave theory can get a satisfaction result in complex areas.In this article, on the base of studis and comparision of many static correction methods, author research tomographic inversion static correction method from both the forward and inversion. In terms of the forward, on the base of grid shortest path algorithm and Fermat ray theory, a method of shortest path raytracing by iterative optimization was come up. The method was applied to theoretical model and excellent effect has been obtained. On the base of two-dimensional forward model, author research method of shortest path raytracing by iterative optimization in three-dimensional. In terms of the inversion, focus on a solving, author come up a fuzzy math method the reverse equations. On the base of forward and inversion method, author purpose a fuzzy tomographic inversion static correction method,apply the method to processing the practical seismic data and gets good effect. There are low-depression layers velocity data in some areas, the fuzzy tomographic inversion static correction method can get good effects, but in some arear where are not low-depression layers velocity data, the method get very poor effect. The main explanation to these results is that exact fuzzy rule can not be set up in these area. The problem needs further research and summarization.