A High-Precision Elastic Reverse-Time Migration for Complex Geologic Structure Imaging in Applied Geophysics

Abstract

High-precision elastic reverse-time migration (ERTM) imaging has always been one of the trends in the development of geophysics. However, current wavefield simulations using time-domain finite-difference (FD) approaches in ERTM have second-order temporal accuracy, resulting in travel time changes and waveform distortion in wavefield propagation with large time steps, i.e., temporal dispersion. Errors caused by the temporal dispersion can lead to erroneous imaging locations and out-of-focus diffraction events. A new ERTM and its workflow are established here using temporal and spatial high-order FD accuracy wavefields and the vector-based imaging condition. Our method computes elastic vector-based wavefields by solving a P- and S-wave decomposition form of a quasi-stress–velocity equation. An advanced finite-difference scheme is employed in the wavefield solution to achieve simulation with temporal fourth-order accuracy and spatial arbitrary even-order accuracy. The normalized dot-product imaging condition of the source and receiver P/S wavefields is then applied to generate high-quality images. The elastic wavefield simulation and ERTM numerical examples presented here reveal that the anti-dispersion workflow can improve modeling and imaging accuracy. In addition, the field data application shows that our method can achieve reasonable and reliable ERTM images. This method can integrate the most advanced imaging techniques into this computational framework to improve imaging accuracy.

Comparative Study of 2D Lattice Boltzmann Models for Simulating Seismic Waves

“…Seismic numerical simulation is a crucial research method in seismology, providing valuable insights into the mechanism of earthquakes, seismic event prediction, risk assessment, exploration of the Earth's internal structure, oil and gas exploration, and resource development. Additionally, seismic modeling forms the foundation for full-waveform inversion [1][2][3][4][5][6][7] and reverse-time migration [8][9][10][11][12][13][14], and aids seismic interpretation.…”

Three-Dimensional Ultrasonic Reverse-Time Migration Imaging of Submarine Pipeline Nondestructive Testing in Cylindrical Coordinates

“…In order to circumvent such difficulties, modern ultrasonic testing techniques often involve full acoustic or elastic wave-equation modeling. In this paper, we address the 3D ultrasonic imaging of a pipeline using the reverse-time migration (RTM) technique, which has received much attention in the field of geophysics [35][36][37][38][39]. In recent years, RTM methods, originating from seismic imaging, have gained popularity in ultrasonic nondestructive testing applications [40][41][42][43].…”

Three-dimensional elastic reverse-time migration using a high-order temporal and spatial staggered-grid finite-difference scheme

“…Though full-waveform inversion using SGFD with the highorder accuracy in time has been proposed (Fang et al, 2020;Ren et al, 2021), 3D ERTM with a temporal high-order SGFD method has not been reported. We take our previous numerical simulation and migration imaging work (Chen et al, 2016b;Fang et al, 2022a) a step further toward the 3D ERTM workflow, improving parts such as source and receiver wavefield simulation, wavefield reconstruction, and MPI parallelism using GPUs (Fang et al, 2022b). We develop a high-accuracy 3D ERTM workflow based on a P/S decoupled quasi-stress-velocity elastic equation, solved by using the SGFD method with high-order accuracy in time and space.…”