Sparse-node regional study from acquisition to imaging

Abstract

Sparse node acquisition has become a standard approach to improve the earth model by the addition of ultra-long offsets. The new designs of node data collections coupled with simultaneous shooting can be deployed on a regional basis covering thousands of square kilometers in a cost-effective manner. In complex geological settings including irregular salt geometry, the salt interpretation has a direct impact on subsalt imaging, however salt interpretation can be quite time-intensive and challenging. Full-waveform inversion (FWI), as a data-driven optimization algorithm with full wavefield modeling, has become one of the essential tools for earth model building. However, its use in the salt tectonic contexts, especially with streamer data collection, is limited since the frequencies acquired are not sufficiently low and the offsets sufficiently long. The recent development of robust objective functions allows the application of FWI workflow on OBN surveys in the deep water environment in the Gulf of Mexico, to refine the salt geometry and correct the background velocity error in subsalt to improve the structure configuration in the subsalt.