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Pre-stack Reverse Time Migration Based on Layered Mapping Method for Irregular Surface
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, cp-451-00582
Abstract
Traditional FD method has some difficulties in treating irregular surface, while mapping method can overcome the disadvantage by transform the irregular surface to horizontal surface. But in the meantime, the interface below the surface is transformed to more complex interface, resulting in the inaccurate of wave propagation and imaging. In this paper, a layered mapping method is proposed and is applied to elastic wave RTM. This method not only can overcome the effects of irregular surface but also the underground structure can not be destroyed. Wave field forward continuation, reverse time continuation and separation are completed in auxiliary system coordinate while imaging in Cartesian. Numerical examples of simple surface topography model and complex surface topography model show the correctness of the method proposed in the paper. After testing two extreme cases of inaccurate interface elevation we can find out that the imaging results using layered mapping RTM are much better than that using traditional mapping RTM.