Reverse-time Migration Method Study with High Efficiency Under Complex Conditions
|School||China University of Petroleum|
|Course||Earth Exploration and Information Technology|
|Keywords||Reverse-time migration Imaging advantage Computation bottleneck Calculation strategy Removing migration noise|
Reverse-time migration implements the wavefield continuation with two-way wave equation, avoids to approximate the wave equation, and there is no decomposition of wave equation, it applies the solution of wave equation to the wavefield continuation directly, therefore it has no dip limitation, can image turning wave, the prism waves, constringe and focus multiple in principle, and is the most effective seismic pre-stack depth imaging method, however, its large amount of computation and algorithm limitations restrain its practicability.In this paper, I describe the basic theory of reverse-time migration, solve the two-way wave equation with high-order finite difference, derive the high-order finite difference wavefield continuation formula, and achieve pre-stack reverse-time migration using this formula. This thesis mainly analyses the imaging advantages and computation bottlenecks of reverse-time migration imaging method, research various methods that can improve the computation efficiency and imaging effect of reverse-time migration. In view of the large amount of computation and memory requirement, I analyze the corresponding calculation strategy, and combining with the parallel algorithm I test the model and real data. I test the improvement of computational efficiency by different algorithms through model data, compare the imaging results of this method and others, and prove the effectiveness of the reverse-time migration in this thesis and its advantages in imaging complex velocity model in the. In this paper, I analyze different imaging conditions that can be used in reverse-time migration and different methods used to remove imaging noise detailedly, test all the methods, ultimately compare and analyze the results obtained, and verify their different performance and improvement to the imaging results.With the continuous development of seismic exploration, it puts forward higher request to on imaging methods, reverse-time migration that? is suit for rough surface of mountainous region and complex structure will develop constantly; in view of the widely application of wide-azimuth seismic acquisition system, the anisotropic reverse-time migration will also continues to grow and mature.