Geophysicists have widely used Least-squares reverse-time migration (LSRTM)
to obtain high-resolution images of the subsurface. However, LSRTM needs an
accurate velocity model similar to other migration methods. Otherwise, it
suffers from depth estimation errors and out of focus images. Moreover, LSRTM
is computationally expensive and it can suffer from multiple reflections.
Recently, a target-oriented approach to LSRTM has been proposed, which focuses
the wavefield above the target of interest. Remarkably, this approach can be
helpful for imaging below complex overburdens and subsalt domains. Moreover,
this approach can significantly reduce the computational burden of the problem
by limiting the computational domain to a smaller area. Nevertheless,
target-oriented LSRTM still needs an accurate velocity model of the overburden
to focus the wavefield accurately and predict internal multiple reflections
correctly. In recent years, Marchenko redatuming has emerged as a novel
data-driven method that can predict Green's functions at any arbitrary depth,
including all orders of multiples. The only requirement for this method is a
smooth background velocity model of the overburden. Moreover, with Marchenko
double-focusing, one can make virtual sources and receivers at a boundary above
the target and bypass the overburden. This paper proposes a new algorithm for
target-oriented LSRTM, which fits the double-focused data with modeled data at
a boundary above the target of interest. Consequently, our target-oriented
LSRTM algorithm correctly accounts for all orders of overburden-related
multiples, resulting in a significant reduction of the artifacts caused by
overburden internal multiple reflections in the target image compared to
conventional LSRTM.Comment: This preprint is submitted to Geophysical Journal International and
is under review as of this momen