Marchenko-based target replacement, accounting for all orders of multiple reflections

TL;DR

This paper presents a Marchenko-based method for efficiently predicting surface reflection responses for different target zones in seismic monitoring, fully accounting for multiple scattering and wave conversion.

Contribution

It introduces a two-step process that removes the original target response and inserts a new one, enabling rapid updates for changing target zones using only surface data.

Findings

Fully accounts for all orders of multiple scattering.

Efficiently predicts responses for different target zones.

Applicable to elastodynamic cases with wave conversion.

Abstract

In seismic monitoring, one is usually interested in the response of a changing target zone, embedded in a static inhomogeneous medium. We introduce an efficient method which predicts reflection responses 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. The proposed process consists of two main steps. In the first step, the response of the original target zone is removed from the reflection response, using the Marchenko method. In the second step, the modelled response of a new target zone is inserted between the overburden and underburden responses. The method fully accounts for all orders of multiple scattering and, in the elastodynamic case, for wave conversion. For monitoring purposes, only the second step needs to be repeated for each target-zone model. Since the target zone covers only a small part of the entire medium, the proposed method is much more efficient than repeated modelling of the entire reflection response.