Subsalt imaging by target-oriented wavefield least-squares migration: A 3-D field-data example

Subsalt imaging by target-oriented wavefield least-squares migration: A 3-D field-data example

Yaxun Tang and Biondo Biondi

Abstract:

We pose the reflectivity-imaging problem as a linear inversion problem and solve it in the image domain in a target-oriented fashion. The most computationally intensive part of the image-domain inversion is the explicit computation of the Hessian matrix. We show how we can overcome the cost issue by using the phase-encoding technique in the 3-D conical-wave domain. We apply the inversion-based imaging methodology to a 3-D field data set acquired from the Gulf of Mexico (GOM), and we precondition the inversion with non-stationary dip filters, which naturally incorporate interpreted geological information. Numerical examples demonstrate that imaging by regularized inversion successfully recovers the reflectivities from the effects of uneven illumination, yielding images with more balanced amplitudes and higher spatial resolution.