From Differences to Inversion: A New Era for 4D Seismic

“Repeatability is the biggest hurdle in time-lapse monitoring, but it’s also where the opportunity lies. 4D FWI can help address those repeatability challenges.” On this episode, Andrew Geary sits down with Madhav Vyas and Kris Innanen, guest editors for July’s The Leading Edge special section on 4D full-waveform inversion. They explain how 4D FWI goes beyond traditional differencing by fully inverting wavefields, making time-lapse seismic more robust against survey inconsistencies and complex overburden. Listeners will learn why now is the perfect time to adopt 4D FWI, the main technical hurdles around repeatability and uncertainty, and the first steps to take for reservoir monitoring and survey design. KEY TAKEAWAYS > 4D FWI inverts the full wavefield - reflections, refractions, diving waves, multiples - to detect reservoir changes, making it more robust than conventional 4D processing. > Repeatability of surveys and assessing uncertainty are the biggest challenges, but workflows like hypothesis testing, batch FWI, and null-space shuttling help mitigate inversion noise. > High-quality data and accurate physics (elasticity, attenuation, anisotropy) are essential; advances in GPU-driven computation enable faster iterations and richer uncertainty analysis. CALL TO ACTION Read July's The Leading Edge special section on 4D FWI at https://library.seg.org/toc/leedff/44/7, then explore an open-source FWI toolbox. LINKS * Visit https://seg.org/podcasts/episode-265-from-differences-to-inversion-a-new-era-for-4d-seismic for the complete show notes.