Pre-salt Imaging Beneath Volcanic Intrusions in Brazils Santos Basin

Recent offshore deep-water discoveries in the Santos Basin have drawn attention to pre-salt targets; however, seismic imaging in this area has proven to be challenging due to the complex geology and the depth of the pre-salt targets. Volcanic intrusions can also add intricacies to an already complicated geologic setting, creating very complex velocity profiles and limiting the effectiveness of typical tomographic solutions. For this survey in the Santos Basin, we found that even identifying the top of salt (TOS) can be challenging without first evaluating the velocity between the top of volcanic intrusion and the sediments below. Utilizing the improved bandwidth and imaging capabilities of variable-depth streamer acquisition, a new iterative tomographic approach has been developed to image beneath volcanic intrusions, providing a better understanding of the pre-salt targets.