The Application of GPU-based TTI RTM in a Complex Area with Shallow Gas and Fault Shadow - A Case History

Abstract

Advances in computational power and updated programming techniques has made pre-stack Reverse time migration (RTM) algorithm for depth imaging becoming feasible recently. RTM uses full acoustic two-way wave propagation algorithm for both forward and reverse time extrapolation and provides a natural way to deal with large lateral velocity variations and imposes no dip limitations on the images. Survey discussed in this article is a geophysically challenging area to image due to the presence of near-vertical faults and shallow gas across the region. Reverse Time Migration (RTM) algorithms, plus a correction for Tilted Transverse Isotropy (TTI), shows considerable improvement in depth imaging comparison with the Pre-stack Kirchhoff depth migration. The case study undertaken to assess the impact of the imaging flow demonstrates that the TTI-RTM technology can produce significantly improved imaging results not only in the geological complex area like sub-salt area but also in the subtly complex one discussed in this article. Application of our high performance GPU-based RTM algorithms allows us to speed up RTM migration for large projects in such a complex area.