TTI DIT for dirty salt inversion in the Mississippi Canyon area, Gulf of Mexico

Summary For deep-water Gulf of Mexico, accurate salt geometry is critical for subsalt imaging. This requires the definition of both external and internal salt geometries. In recent years, external salt geometry has been improved due to advances in wide azimuth acquisition, long-offset recording, velocity model building, and migration algorithms. In this paper we present the results of dirty salt inversion using TTI RTM technology based on DIT scans. Approximately 42 OCS blocks of the Freedom survey located in the Mississippi Canyon area of the Gulf of Mexico were imaged. The study area was previously imaged with VTI Kirchhoff and RTM technology using a constant salt velocity. Application of TTI DIT for dirty salt using a laterally heterogenous salt velocity has resulted in better base of salt definition and improved subsalt images. Results indicate that intra-salt velocity is slower than salt velocity.