Target-oriented wavefield tomography using synthesized Born data

摘要

We present a new strategy for efficient wave-equationmigration-velocity analysis in complex geological settings.The proposed strategy has two main steps: simulating a newdata set using an initial unfocused image and performingwavefield-based tomography using this data set.We demonstratedthat the new data set can be synthesized by usinggeneralized Born wavefield modeling for a specific targetregion where velocities are inaccurate. We also showed thatthe new data set can be much smaller than the original onebecause of the target-oriented modeling strategy, but it containsnecessary velocity information for successful velocityanalysis. These interesting features make this new data setsuitable for target-oriented, fast and interactive velocitymodel-building. We demonstrate the performance of ourmethod on both a synthetic data set and a field data setacquired from the Gulf of Mexico, where we update the subsaltvelocity in a target-oriented fashion and obtain a subsaltimage with improved continuities, signal-to-noise ratio andflattened angle-domain common-image gathers.