A study of acquisition-related sub-sampling and aperture effects on Marchenko focusing and redatuming

Abstract

Here, we study the effects of imperfect acquisition geometries (i.e., regular source-receiver sub-sampling and limited aperture) on the output focusing functions and Green’s functions from Marchenko redatuming. We do this with examples from a benchmark 4-layer model and a complex salt model. We show that sub-sampling effects jointly depend on the choice of integration variable and the sub-sampling dimension in the multidimensional convolutions within the Marchenko scheme. Because of the source-receiver reciprocity, this can be advantageous in cases when only one of the dimensions (source or receiver) are sub-sampled. For the same reason, when the sampling of reflection data is symmetric with respect to the source and receiver dimensions, integrating on either dimension yields the same result, regardless of sub-sampling. When the data are sub-sampled on one dimension with a uniform sampling interval, integrating on the other dimension yields incorrect focusing results, with gaps at surface locations corresponding to the missing data. However, in this same sampling scenario, integrating on the sub-sampled dimension yields focusing functions with artifacts but no spatial gaps. We observe that sampling-induced artifacts at far offsets are more prominent than those at near offsets, because the correlation gathers between the reflection response and the focusing functions contain events with steeper-slopes at far offsets, so they are more sensitive to integration aliasing than their near-offset counterparts. Limiting the acquisition aperture will also bring artifacts, which can be compounded by the sub-sampling effects, as we show with our salt model example.

Presentation Date: Tuesday, September 17, 2019

Session Start Time: 1:50 PM

Presentation Time: 3:30 PM

Location: Poster Station 11

Presentation Type: Poster