Iterative least-squares migration for high-resolution angle gathers

Seismic amplitudes can be biased by uneven illumination in the presence of a complex overburden. Iterative Least Squares Migration (LSM) can reduce the amplitude bias and improve the resolution of the images. We introduce a robust and practical iterative least-squares migration for the inversion of angle domain common image gathers. The algorithm uses wave-equation migration and demigration in the extended subsurface offset domain followed by an offset to angle transformation. We demonstrate using the Sigsbee2b synthetic and field data from Santos Basin, offshore Brazil that iterative LSM provides high-resolution angle domain common image gathers, extending their usable angle range, and balancing their amplitudes.