Time-lapse monitoring with virtual seismology: Applications of the Marchenko method for observing time-lapse changes in subsurface reservoirs

Monitoring time-lapse changes inside the subsurface is of great significance to many geotechnical applications, such as storage of gasses in underground geological formations. Minute differences in the seismic wavefield between an initial baseline and a subsequent monitor survey have to be detected in order to observe fluid flow inside...

Target-Enclosed Least-Squares Seismic Imaging

Least-squares reverse-time migration (LSRTM) is a method that seismologists utilize to compute a high-resolution subsurface image. Nevertheless, LSRTM is a computationally demanding problem. One way to reduce the computational costs of the LSRTM is to choose a small region of interest (ROI) and compute the image of that region. However, finding...

The propagator and transfer matrix for a 3D inhomogeneous dissipative acoustic medium, expressed in Marchenko focusing functions

Standard Marchenko redatuming and imaging schemes neglect evanescent waves and are based on the assumption that decomposition into downgoing and upgoing waves is possible in the subsurface. Recently we have shown that propagator matrices, which circumvent these assumptions, can be expressed in terms of Marchenko focusing functions. In this paper...

Active and passive monitoring of fault reactivation under stress cycling

Increased seismicity due to subsurface activities has led to increased interest in monitoring and seismic risk mitigation. In this study we combined passive and active acoustic monitoring methods to monitor fault sliding and reactivation in the laboratory. Acoustic emission (AE) and ultrasonic transmission measurements were performed during...

Monitoring and forecasting of seismic wavefields in the subsurface

Monitoring seismic wavefields caused by induced seismicity in the subsurface is a difficult process. Ideally, it requires physical receivers in the subsurface, which is unpractical. Frequently, only measurements at the surface of the Earth are available, which give a limited amount of information about the subsurface. One way to improve the...

Elastodynamic Marchenko inverse scattering: A multiple-elimination strategy for imaging of elastodynamic seismic reflection data

The Marchenko method offers a new perspective on eliminating internal multiples. Instead of predicting internal multiples based on events, the Marchenko method formulates an inverse problem that is solved for an inverse transmission response. This approach is particularly advantageous when internal multiples generate complicated interference...

Wavefield focusing with reduced cranial invasiveness

Wavefield focusing can be achieved by Time-Reversal Mirrors, which involve in- and output signals that are infinite in time and waves propagating through the entire medium. Here, an alternative solution for wavefield focusing is presented. This solution is based on a new integral representation where in- and output signals are finite in time,...

Virtual Sources and Receivers in the Real Earth: Considerations for Practical Applications

To enhance monitoring of the subsurface, virtual sources and receivers inside the subsurface can be created from seismic reflection data at the surface of the Earth using the Marchenko method. The response between these virtual sources and receivers can be obtained through the use of homogeneous Green's function retrieval. A homogeneous Green's...

Marchenko redatuming by adaptive double-focusing on 2D and 3D field data of the Santos basin

The Santos basin in Brazil suffers from strong internal multiples that overlap with primaries from the pre-salt reservoirs. We propose an adaptive double-focusing method for the removal of these multiples to obtain a correct image of the target area. The proposed method applies a form of source-receiver Marchenko redatuming to the reflection...

Enhanced characterization of fracture compliance heterogeneity using multiple reflections and data-driven Green's function retrieval

The spatial heterogeneity along a fracture is a key determinant for fracture-associated mechanical and hydraulic properties of the subsurface. Laboratory experiments have been performed to test the applicability of the nonwelded interface representation to predict the frequency- and angle-dependent elastic response of a single fracture. The...

Data-driven Green's function retrieval and application to imaging with multidimensional deconvolution

An iterative method is presented that allows one to retrieve the Green's function originating from a virtual source located inside a medium using reflection data measured only at the acquisition surface. In addition to the reflection response, an estimate of the travel times corresponding to the direct arrivals is required. However, no detailed...