Capturing elusive subsalt 4D signals in Atlantis field with 4D elastic FWI imaging Available to Purchase

Obtaining 4D (time-lapse) signals underneath complex salt canopies has been incredibly challenging. In addition to nonrepeatable factors between baseline and monitor surveys that degrade 4D signals, such as source/receiver position variations and water column changes, the weak and imbalanced illumination in subsalt areas stands as a significant bottleneck, often resulting in poor 3D images and even worse 4D images, with signals nowhere to be found against the noisy background. In recent years, full-waveform inversion (FWI) Imaging, especially elastic FWI Imaging, has shown to be a superior method for providing subsalt images with greatly improved illumination, signal-to-noise ratio (S/N), and focusing over conventional imaging methods. Therefore, it is natural to extend the application of FWI Imaging from 3D to 4D subsalt imaging, though the feasibility has never been confirmed before. Here, we made the first attempt to apply Elastic Time-lag FWI (E-TLFWI) Imaging on Atlantis 4D data sets. Encouragingly, results from 4D E-TLFWI Imaging reveal much clearer subsalt 4D signals with significantly improved 4D S/N and more accurate 4D responses that are substantiated by both well findings and production history.