Research On Angle-dependent Tomographic Static Correction

Reflection data in CMP has influenced seriously in static calculations,especially in some highly weathered and structurally altered circumstances. Inorder that, following problems and actual requirements in static correction, weimplement research on tomography static correction. This essay indicates the basictheory of tomography static correction, including the establishment of forwardmodel, the calculation theory of tomography and angle-dependent tomographystatic correction. Tomography ray tracing the development of methods, and staticcorrection methods of research are summarized in this essay.The usage of theoretical models and practical information on the method hasbeen validated. The results show that using the above methods to calculate staticcorrection of a complex area, static correction's quality has been greatlyimproved.On the contrary, the tomographic static correction techniques could befully satisfied on the surface complex area, mainly in the following three reasons:1.the conventional static correction in complex areas, the biggest limitation is thatfirst break contains diffracted waves and refracted waves, however, tomographicstatic correction do not need to distinguish between these waves.2. tomographicstatic correction could solve lateral vitiations of velocity and surface undulatingproblems, do not need to consider the issue of control points. On the other hand,tomographic static correction technique can also be a good combination with thefield surface investigation techniques, which is used to revise observation the speedinformation of the position.3. the first break in its propagation distance is shortthat makes is easy to avoid the interrupt wave, these are the preconditions of usingfirst break to solve static correction problems.Conventional static correction is a kind of simple principle, less calculationand effective method. In simple surface conditions, this method could basicallysatisfied the actual needs, however in complex surface area, method could not meetrequirements. Reasons are as follows: In the complex area of undulating terrainwhich near surface velocity strongly changed, the first break always containsdiffracted waves and refracted waves which generated by the complex geologicalstructure. Consequently, conventional static correction method is not suitable for high weathered layer model.