Addressing Geometry Variations in a Multisurvey Ocean-Bottom Seismic Surveys using FWI with Illumination Probing Method

Advancements in full-waveform inversion (FWI) have enabled reimaging of vintage surveys with varying geometries. Gradient balancing is crucial but traditionally manual and error-prone, especially with overlapping data. Xu et al. (2024) introduced an illumination probing method using synthetic data simulation with real survey sources and receivers, offering a cost-effective approach with minimal user intervention and improved consistency. This study applies the method to three surveys in the Oseberg South field on the Norwegian Continental Shelf, each with different acquisition parameters. Synthetic data generates gradients independently for each survey, scaled based on root mean square (RMS) values before stacking. This creates a gradient balancing mask that equalizes inversion gradients in overlapping areas and addresses illumination gaps. Results demonstrate that the illumination probing method effectively compensates for survey illumination variations, producing well-balanced gradients and more accurate subsurface models. Compared to conventional techniques, it offers faster convergence and superior updates, enhancing image quality and resolution, particularly in challenging sedimentary regions.