LSRTM of One Plane-wave Gather

Figure (a) shows the migration image of one plane-wave gather with a zero-degree shooting angle at the surface. It contains strong aliasing artifacts. In this image, some of the steeply dipping reflectors are not illuminated by the zero-degree plane wave. In addition, the deep reflectors are poorly imaged because the planar wavefront is disrupted by shallow structures before it propagates to the deep part and the reflections from deep reflectors are rendered weak and incoherent. Applying the LSRTM method to this plane-wave gather gives the image in Figure (b) after 30 iterations. Compared to Figures and (a), the aliasing artifacts are largely suppressed in the LSRTM image and those steeply dipping structures are well illuminated. The LSRTM image also shows enhanced resolution in the shallow part. However, this image contains strong high-frequency noise in the deep portion of the model.

Figure: The plane-wave RTM image of the Marmousi2 model with only one angle ($p=0$ ); (b) The plane-wave LSRTM image of the marmousi2 Model with only one angle ($p=0$ ) after 30 iterations; and (c) The plane-wave LSRTM image of the Marmousi2 model with only one angle per iteration. The angle is dynamically changed at every iteration.