Using inverse transmission matrices for Marchenko redatuming in highly complex media

Abstract

The goal of Marchenko redatuming is to reconstruct, from single-sided reflection data, wavefields at virtual subsurface locations containing transmitted and reflected primaries and internal multiples, while relying on limited or no knowledge of discontinuties in subsurface properties. Here, we address the limitations of the current Marchenko scheme in retrieving waves in highly heterogeneous media, such as subsalt or subbasalt. We focus on the initial focusing function that plays a key role in the iterative scheme, and propose an alternative focusing function that uses an estimate of the inverse transmission operator from a reference model that contains sharp contrasts (e.g., salt boundaries). Using a physics-driven estimate of the inverse transmission operator, we demonstrate that the new approach retrieves improved subsurface wavefields, including enhanced amplitudes and internal multiples, in a subsalt environment.