Phaseless Imaging by Reverse Time Migration: Acoustic Waves

AbstractWe propose a reliable direct imaging method based on the reverse time migration for finding extended obstacles with phaseless total field data. We prove that the imaging resolution of the method is essentially the same as the imaging results using the scattering data with full phase information when the measurement is far away from the obstacle. The imaginary part of the cross-correlation imaging functional always peaks on the boundary of the obstacle. Numerical experiments are included to illustrate the powerful imaging quality

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Diffraction imaging for fault-karst structure by least-squares reverse time migration

Interpretation ◽

10.1190/int-2020-0146.1 ◽

2020 ◽

pp. 1-40

Author(s):

Xinru Mu ◽

Jianping Huang ◽

Liyun Fu ◽

Shikai Jian ◽

Bing Hu ◽

...

Keyword(s):

Least Squares ◽

Western China ◽

Small Scale ◽

Imaging Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Migration ◽

Imaging Results ◽

Heterogeneous Structures ◽

Karst Reservoir

The fault-karst reservoir, which evolved from the deformation and karstification of carbonate rock, is one of the most important reservoir types in western China. Along the deep-seated fault zones, there are a lot widely spread and densely distributed fractures and vugs. The energy of the diffractions generated by heterogeneous structures, such as faults, fractures and vugs, are much weaker than that of the reflections produced by continuous formation interface. When using conventional full wavefield imaging method, the imaging results of continuous layers usually cover small-scale heterogeneities. Given that, we use plane-wave destruction (PWD) filter to separate the diffractions from the full data and image the separated diffractions using least-squares reverse time migration (LSRTM) method. We use several numerical examples to demonstrate that the newly developed diffractions LSRTM (D-LSRTM) can improve the definition of the heterogeneous structures, characterize the configuration and internal structure of the fault-karst structure well and enhance the interpretation accuracy for fault-karst reservoir.

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Reverse Time Migration Using the Pseudospectral Time-Domain Algorithm

Journal of Computational Acoustics ◽

10.1142/s0218396x16500053 ◽

2016 ◽

Vol 24 (02) ◽

pp. 1650005 ◽

Cited By ~ 6

Author(s):

Jiangang Xie ◽

Zichao Guo ◽

Hai Liu ◽

Qing Huo Liu

Keyword(s):

Time Domain ◽

Acoustic Waves ◽

Fdtd Method ◽

Pseudospectral Method ◽

Imaging Method ◽

Processing Unit ◽

Reverse Time ◽

Reverse Time Migration ◽

Eighth Order ◽

Time Migration

We propose a pre-stack reverse time migration (RTM) seismic imaging method using the pseudospectral time-domain (PSTD) algorithm. Traditional pseudospectral method uses the fast Fourier transform (FFT) algorithm to calculate the spatial derivatives, but is limited by the wraparound effect due to the periodicity assumed in the FFT. The PSTD algorithm combines the pseudospectral method with a perfectly matched layer (PML) for acoustic waves. PML is a highly effective absorbing boundary condition that can eliminate the wraparound effect. It enables a wide application of the pseudospectral method to complex models. RTM based on the PSTD algorithm has advantages in the computational efficiency compared to traditional methods such as the second-order and high order finite difference time-domain (FDTD) methods. In this work, we implement the PSTD algorithm for acoustic wave equation based RTM. By applying the PSTD-RTM method to various seismic models and comparing it with RTM based on the eighth-order FDTD method, we find that PSTD-RTM method has better performance and saves more than 50% memory. The method is suitable for parallel computation, and has been accelerated by general purpose graphics processing unit.

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Amplitude-preserving scalar PP and PS imaging condition for elastic reverse time migration based on a wavefield decoupling method

Geophysics ◽

10.1190/geo2017-0840.1 ◽

2019 ◽

Vol 84 (3) ◽

pp. S113-S125 ◽

Cited By ~ 1

Author(s):

Xiyan Zhou ◽

Xu Chang ◽

Yibo Wang ◽

Zhenxing Yao

Keyword(s):

Wave Vector ◽

Numerical Models ◽

P Wave ◽

Imaging Method ◽

Reverse Time ◽

Reverse Time Migration ◽

S Wave ◽

Decoupling Method ◽

Time Migration ◽

Imaging Results

To eliminate crosstalk within the imaging results of elastic reverse time migration (ERTM), we can separate the coupled P- and S-waves from the forward source wavefield and the backpropagated receiver wavefield. The P- and S-wave decoupling method retains the original phase, amplitude, and physical meaning in the separated wavefields. Thus, it is a vital wavefield separation method in ERTM. However, because these decomposed wavefields are vectors, we could consider how to retrieve scalar images that reveal the real reflectivity of the subsurface. For this purpose, we derive a scalar P-wave equation from the velocity-stress relationship for PP imaging. The phase and amplitude of this scalar P-wave are consistent with the scalarized P-wave. Therefore, this scalar P-wave can be exploited to perform PP imaging directly, with the imaging result retaining the amplitude characteristics. For PS imaging, it is difficult to calculate a dynamic preserved scalar S-wave. However, we have developed a scalar PS imaging method that divides the PS image into energy and sign components according to the geometric relationship between the wavefield vibration and propagation directions. The energy is calculated through the amplitude crosscorrelation of the forward P-wave and backpropagated S-wave from the receivers. The sign is obtained from the dot product of the forward P-wave vector and the backpropagated S-wave vector. These PP and PS imaging methods are suitable for 2D and 3D isotropic media and maintain the correct amplitude information while eliminating polarity-reversal phenomena. Several numerical models are used to verify the robustness and effectiveness of our method.

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Receiver grouping strategies for hybrid Geometric-mean Reverse-time migration

Geophysics ◽

10.1190/geo2021-0428.1 ◽

2021 ◽

pp. 1-52

Author(s):

Tong Bai ◽

Bin Lyu ◽

Paul Williamson ◽

Nori Nakata

Keyword(s):

Time Reversal ◽

Cross Correlation ◽

Geometric Mean ◽

Random Noise ◽

Imaging Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Image Domain ◽

Time Migration ◽

Grouping Strategies

Geometric-mean Reverse-time migration (GmRTM), a powerful cross-correlation-based imaging method, generates higher-resolution source images and is more robust to noise compared to conventional time-reversal imaging. The price to pay is the higher computational costs. Alternatively, we can adopt hybrid strategies by dividing the receivers into different groups. Conventional time reversal (i.e., wavefield summation) is performed inside each group, followed by the application of cross-correlation imaging condition among different groups. Such hybrid strategies can retain the advantages of both GmRTM and time-reversal, and are often more practical than pure GmRTM. Yet, designing appropriate grouping strategy is not trivial. Here, we propose two grouping strategies (adjacent and scattered) and use synthetic and field-data examples to evaluate their performance with various group numbers. In addition to the spatial resolution of the source image, robustness to random noise is another important assessment criterion, for which we consider two distribution patterns, such as concentrated and scattered, of traces contaminated with strong random noise. We also evaluated their effectiveness to visualize events (in the image domain) that are not completely recorded by all receivers. Our comprehensive tests illustrate the respective advantages of the two grouping strategies.

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Lamb-wave-based two-dimensional areal scan damage imaging using reverse-time migration with a normalized zero-lag cross-correlation imaging condition

Structural Health Monitoring ◽

10.1177/1475921716674373 ◽

2016 ◽

Vol 16 (4) ◽

pp. 444-457 ◽

Cited By ~ 13

Author(s):

Jiaze He ◽

Fuh-Gwo Yuan

Keyword(s):

Lamb Wave ◽

Cross Correlation ◽

Two Dimensional ◽

Reverse Time ◽

Reverse Time Migration ◽

Imaging Condition ◽

Time Migration ◽

Damage Imaging

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An efficient local operator-based Q-compensated reverse time migration algorithm with multistage optimization

Geophysics ◽

10.1190/geo2017-0026.1 ◽

2018 ◽

Vol 83 (3) ◽

pp. S249-S259 ◽

Cited By ~ 5

Author(s):

Tong Zhou ◽

Wenyi Hu ◽

Jieyuan Ning

Keyword(s):

Seismic Attenuation ◽

Depth Information ◽

Frequency Noise ◽

Processing Unit ◽

Reverse Time ◽

Reverse Time Migration ◽

Pass Filter ◽

Low Pass Filter ◽

Time Migration ◽

Imaging Results

Most existing [Formula: see text]-compensated reverse time migration ([Formula: see text]-RTM) algorithms are based on pseudospectral methods. Because of the global nature of pseudospectral operators, these methods are not ideal for efficient parallelization, implying that they may suffer from high computational cost and inefficient memory usage for large-scale industrial problems. In this work, we reported a novel [Formula: see text]-RTM algorithm — the multistage optimized [Formula: see text]-RTM method. This [Formula: see text]-RTM algorithm uses a finite-difference method to compensate the amplitude and the phase simultaneously by uniquely combining two techniques: (1) a negative [Formula: see text] method for amplitude compensation and (2) a multistage dispersion optimization technique for phase correction. To prevent high-frequency noise from growing exponentially and ruining the imaging results, we apply a finite impulse response low-pass filter using the Kaiser window. The theoretical analyses and numerical experiments demonstrate that this [Formula: see text]-RTM algorithm precisely recovers the decayed amplitude and corrects the distorted phase caused by seismic attenuation effects, and hence produces higher resolution subsurface images with the correct structural depth information. This new method performs best in the frequency range of 10–70 Hz. Compared with pseudospectral [Formula: see text]-RTM methods, this [Formula: see text]-RTM approach offers nearly identical imaging quality. Based on local numerical differential operators, this [Formula: see text]-RTM method is very suitable for parallel computing and graphic processing unit implementation, an important feature for large 3D seismic surveys.

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Near-Borehole Imaging Using Full-Waveform Sonic Data

10.2118/204765-ms ◽

2021 ◽

Author(s):

Hala Alqatari ◽

Thierry-Laurent Tonellot ◽

Mohammed Mubarak

Keyword(s):

Seismic Data ◽

Reverse Time ◽

Reverse Time Migration ◽

Full Waveform ◽

Time Migration ◽

Imaging Results ◽

High Resolution Images ◽

Recorded Data ◽

The Impact ◽

Processing Steps

Abstract This work presents a full waveform sonic (FWS) dataset processing to generate high-resolution images of the near-borehole area. The dataset was acquired in a nearly horizontal well over a distance of 5400 feet. Multiple formation boundaries can be identified on the final image and tracked at up to 200 feet deep, along the wellbore's trajectory. We first present a new preprocessing sequence to prepare the sonic data for imaging. This sequence leverages denoising algorithms used in conventional surface seismic data processing to remove unwanted components of the recorded data that could harm the imaging results. We then apply a reverse time migration algorithm to the data at different processing stages to assess the impact of the main processing steps on the final image.

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Some Aspects of Seismic Data Reverse Time Migration for Salt Tectonics Geology of the Dnieper-Donets Basin

10.2118/208531-ms ◽

2021 ◽

Author(s):

Pavlo Kuzmenko ◽

Viktor Buhrii ◽

Carlo D'Aguanno ◽

Viktor Maliar ◽

Hrigorii Kashuba ◽

...

Keyword(s):

Seismic Data ◽

Full Range ◽

Donets Basin ◽

Salt Tectonics ◽

Imaging Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Migration ◽

Seismic Image ◽

Complex Geology

Abstract Processing of the seismic data acquired in areas of complex geology of the Dnieper-Donets basin, characterized by the salt tectonics, requires special attention to the salt dome interpretation. For this purpose, Kirchhoff Depth Imaging and Reverse Time Migration (RTM) were applied and compared. This is the first such experience in the Dnieper-Donets basin. According to international experience, RTM is the most accurate seismic imaging method for steep and vertical geological (acoustic contrast) boundaries. Application of the RTM on 3D WAZ land data is a great challenge in Dnieper-Donets Basin because of the poor quality of the data with a low signal-to-noise ratio and irregular spatial sampling due to seismic acquisition gaps and missing traces. The RTM algorithm requires data, organized to native positions of seismic shots. For KPSDM we used regularized data after 5D interpolation. This affects the result for near salt reflection. The analysis of KPSDM and RTM results for the two areas revealed the same features. RTM seismic data looked more smoothed, but for steeply dipping reflections, lateral continuity of reflections was much improved. The upper part (1000 m) of the RTM has shadow zones caused by low fold. Other differences between Kirchhoff data and RTM are in the spectral content, as the former is characterized by the full range of seismic frequency spectrum. Conversely, beneath the salt, the RTM has reflections with steep dips which are not observed on the KPSDM. It is possible to identify new prospects using the RTM seismic image. Reverse Time Migration of 3D seismic data has shown geologically consistent results and has the potential to identify undiscovered hydrocarbon traps and to improve salt flank delineation in the complex geology of the Dnieper-Donets Basin's salt domes.

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Least-squares reverse time migration via linearized waveform inversion using a Wasserstein metric

Geophysics ◽

10.1190/geo2018-0619.1 ◽

2019 ◽

Vol 84 (5) ◽

pp. S411-S423

Author(s):

Peng Yong ◽

Jianping Huang ◽

Zhenchun Li ◽

Wenyuan Liao ◽

Luping Qu

Keyword(s):

Least Squares ◽

Waveform Inversion ◽

Synthetic Data ◽

Gradient Algorithm ◽

Reverse Time ◽

Reverse Time Migration ◽

Wasserstein Metric ◽

Time Migration ◽

Imaging Results ◽

Primal Dual

Least-squares reverse time migration (LSRTM), an effective tool for imaging the structures of the earth from seismograms, can be characterized as a linearized waveform inversion problem. We have investigated the performance of three minimization functionals as the [Formula: see text] norm, the hybrid [Formula: see text] norm, and the Wasserstein metric ([Formula: see text] metric) for LSRTM. The [Formula: see text] metric used in this study is based on the dynamic formulation of transport problems, and a primal-dual hybrid gradient algorithm is introduced to efficiently compute the [Formula: see text] metric between two seismograms. One-dimensional signal analysis has demonstrated that the [Formula: see text] metric behaves like the [Formula: see text] norm for two amplitude-varied signals. Unlike the [Formula: see text] norm, the [Formula: see text] metric does not suffer from the differentiability issue for null residuals. Numerical examples of the application of three misfit functions to LSRTM on synthetic data have demonstrated that, compared to the [Formula: see text] norm, the hybrid [Formula: see text] norm and [Formula: see text] metric can accelerate LSRTM and are less sensitive to non-Gaussian noise. For the field data application, the [Formula: see text] metric produces the most reliable imaging results. The hybrid [Formula: see text] norm requires tedious trial-and-error tests for the judicious threshold parameter selection. Hence, the more automatic [Formula: see text] metric is recommended as a robust alternative to the customary [Formula: see text] norm for time-domain LSRTM.

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