Seismic time-lapse imaging using interferometric least-squares migration: Case study: ILSM time-lapse

Seismic time-lapse surveys are susceptible to repeatability errors due to varying environmental conditions. To mitigate this problem, we propose the use of interferometric least-squares migration to estimate the migration images for the baseline and monitor surveys. Here, a known reflector is used as the reference reflector for interferometric least-squares migration, and the data are approximately redatumed to this reference reflector before imaging. This virtual redatuming mitigates the repeatability errors in the time-lapse migration image. Results with synthetic and field data show that interferometric least-squares migration can sometimes reduce or eliminate artifacts caused by non-repeatability in time-lapse surveys and provide a high-resolution estimate of the time-lapse change in the reservoir.