Abstract
Seismic time-lapse studies are generally concerned with variations in a
specific target zone, situated inside an otherwise static medium. In
seismic monitoring the entire reflection response at the surface needs
to be remodeled for every change in the target zone. Ideally, however,
only the response of the target zone is remodeled, which is then
inserted into the stationary response of the surrounding medium. Such an
insertion is relatively straightforward when solely primary reflections
are considered, but more complicated when internal multiples are
introduced. The data-driven Marchenko method retrieves the responses to
virtual sources inside the subsurface, and fully accounts for all orders
of multiple scattering. Wapenaar and Staring (2018), therefore, use the
method to predict the reflection response at the Earth’s surface for
different target-zone scenarios, from a single reflection response at
the surface and a model of the changing target zone. This is achieved in
two steps. First, the responses of the static overand underburden are
resolved from the reflection response. Second, the newly modeled
response from the target zone is inserted. While this methodology was
originally only tested for laterally invariant media, we show how it can
be extended for laterally inhomogeneous media. A 2D model is considered
to compare the performance of the Marchenko-based replacement with a
remodeled response of the entire medium. The results show that the
method accurately captures the different arrivals in the reflection
response, including the multiples, aside from minor differences in
amplitude. We conclude that the method can be used to more efficiently
model reflection responses of variable target zones, therefore, enabling
more effective modeling for time-lapse monitoring.