Reverse Time Migration Using the Pseudospectral Time-Domain Algorithm

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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Phaseless Imaging by Reverse Time Migration: Acoustic Waves

Numerical Mathematics Theory Methods and Applications ◽

10.4208/nmtma.2017.m1617 ◽

2017 ◽

Vol 10 (1) ◽

pp. 1-21 ◽

Cited By ~ 23

Author(s):

Zhiming Chen ◽

Guanghui Huang

Keyword(s):

Acoustic Waves ◽

Numerical Experiments ◽

Cross Correlation ◽

Scattering Data ◽

Imaging Method ◽

Total Field ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Migration ◽

Imaging Results

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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Reverse Time Migration of Elastic Waves Using the Pseudospectral Time-Domain Method

Journal of Theoretical and Computational Acoustics ◽

10.1142/s2591728517500335 ◽

2018 ◽

Vol 26 (01) ◽

pp. 1750033 ◽

Cited By ~ 1

Author(s):

Jiangang Xie ◽

Mingwei Zhuang ◽

Zichao Guo ◽

Hai Liu ◽

Qing Huo Liu

Keyword(s):

Elastic Wave ◽

Time Domain ◽

Elastic Waves ◽

Sampling Rate ◽

Fdtd Method ◽

Time Domain Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Migration ◽

Domain Method

Reverse time migration (RTM), especially that for elastic waves, consumes massive computation resources which limit its wide applications in industry. We suggest to use the pseudospectral time-domain (PSTD) method in elastic wave RTM. RTM using PSTD can significantly reduce the computational requirements compared with RTM using the traditional finite difference time domain method (FDTD). In addition to the advantage of low sampling rate with high accuracy, the PSTD method also eliminates the periodicity (or wraparound) limitation caused by fast Fourier transform in the conventional pseudospectral method. To achieve accurate results, the PSTD method needs only about half the spatial sampling rate of the twelfth-order FDTD method. Thus, the PSTD method can save up to 87.5% storage memory and 90% computation time over the twelfth-order FDTD method. We implement RTM using PSTD for elastic wave equations and accelerate it by Open Multi-Processing technology. To keep the computational load balance in parallel computation, we design a new PML layout which merges the PML in both ends of an axis together. The efficiency and imaging quality of the proposed RTM is verified by imaging on 2D and 3D models.

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Angle gathers from reverse time migration using analytic wavefield propagation and decomposition in the time domain

Geophysics ◽

10.1190/geo2015-0050.1 ◽

2016 ◽

Vol 81 (1) ◽

pp. S1-S9 ◽

Cited By ~ 20

Author(s):

Jiangtao Hu ◽

Huazhong Wang ◽

Xiongwen Wang

Keyword(s):

Plane Wave ◽

Time Domain ◽

Computational Cost ◽

Imaging Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Imaging Condition ◽

Time Migration ◽

Local Plane ◽

The Time Domain

Angle-domain common imaging gathers (ADCIGs) are important input data for migration velocity analysis and amplitude variation with angle analysis. Compared with Kirchhoff migration and one-way wave equation migration, reverse time migration (RTM) is the most accurate imaging method in complex areas, such as the subsalt area. We have developed a method to generate ADCIGs from RTM using analytic wavefield propagation and decomposition. To estimate the wave-propagation direction and angle by spatial Fourier transform during the time domain wave extrapolation, we have developed an analytic wavefield extrapolation method. Then, we decomposed the extrapolated source and receiver wavefields into their local angle components (i.e., local plane-wave components) and applied the angle-domain imaging condition to form ADCIGs. Because the angle-domain imaging condition is a convolution imaging condition about the source and receiver propagation angles, it is costly. To increase the efficiency of the angle-domain imaging condition, we have developed a local plane-wave decomposition method using matching pursuit. Numerical examples of synthetic and real data found that this method could generate high-quality ADCIGs. And these examples also found that the computational cost of this approach was related to the complexity of the source and receiver wavefields.

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Viscoacoustic least-squares reverse time migration using a time-domain complex-valued wave equation

Geophysics ◽

10.1190/geo2018-0804.1 ◽

2019 ◽

Vol 84 (5) ◽

pp. S479-S499 ◽

Cited By ~ 3

Author(s):

Jidong Yang ◽

Hejun Zhu

Keyword(s):

Wave Equation ◽

Least Squares ◽

Time Domain ◽

Inverse Operator ◽

Total Variation Regularization ◽

Imaging Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Migration ◽

Complex Valued

With limited recording apertures, finite-frequency source functions, and irregular subsurface illuminations, traditional imaging methods have been insufficient to produce satisfactory reflectivity images with high resolution and amplitude fidelity. This is because most traditional imaging approaches are commonly formulated as the adjoint instead of the inverse operator with respect to the forward-modeling operator. In addition, intrinsic attenuation introduces amplitude loss and phase dispersion during wave propagation. Without considering these effects, migrated images might be kinematically and dynamically incorrect. We have developed a viscoacoustic least-squares reverse time migration (LSRTM) method based on a time-domain complex-valued wave equation. According to the Born approximation, we first linearized the viscoacoustic wave equation and derived a demigration operator. Then, using the complex-valued Lagrange multiplier method, we derived the adjoint viscoacoustic wave equation and corresponding sensitivity kernel. With the forward and adjoint operators, a linear inverse problem is formulated to estimate the subsurface reflectivity model. A total-variation regularization scheme is introduced to enhance the robustness of our viscoacoustic LSRTM, and a diagonal Hessian is used as the preconditioner to accelerate the convergence. Three synthetic examples are used to demonstrate that our approach enables us to compensate attenuation effects, improve imaging resolution, and enhance amplitude fidelity in comparison with the adjoint imaging method.

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Reverse time migration angle gathers using Poynting vector and pseudospectral method

10.1190/segam2017-17749395.1 ◽

2017 ◽

Author(s):

Kwangjin Yoon

Keyword(s):

Poynting Vector ◽

Pseudospectral Method ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Migration

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Fast plane-wave reverse time migration

Geophysics ◽

10.1190/geo2017-0688.1 ◽

2018 ◽

Vol 83 (6) ◽

pp. S549-S556 ◽

Cited By ~ 1

Author(s):

Xiongwen Wang ◽

Xu Ji ◽

Hongwei Liu ◽

Yi Luo

Keyword(s):

Time Delay ◽

Plane Wave ◽

Green’S Function ◽

Green's Function ◽

Time Domain ◽

Reverse Time ◽

Reverse Time Migration ◽

Wave Source ◽

Computation Cost ◽

Time Migration

Plane-wave reverse time migration (RTM) could potentially provide quick subsurface images by migrating fewer plane-wave gathers than shot gathers. However, the time delay between the first and the last excitation sources in the plane-wave source largely increases the computation cost and decreases the practical value of this method. Although the time delay problem is easily overcome by periodical phase shifting in the frequency domain for one-way wave-equation migration, it remains a challenge for time-domain RTM. We have developed a novel method, referred as to fast plane-wave RTM (FP-RTM), to eliminate unnecessary computation burden and significantly reduce the computational cost. In the proposed FP-RTM, we assume that the Green’s function has finite-length support; thus, the plane-wave source function and its responding data can be wrapped periodically in the time domain. The wrapping length is the assumed total duration length of Green’s function. We also determine that only two period plane-wave source and data after the wrapping process are required for generating the outcome with adequate accuracy. Although the computation time for one plane-wave gather is twice as long as a normal shot gather migration, a large amount of computation cost is saved because the total number of plane-wave gathers to be migrated is usually much less than the total number of shot gathers. Our FP-RTM can be used to rapidly generate RTM images and plane-wave domain common-image gathers for velocity model building. The synthetic and field data examples are evaluated to validate the efficiency and accuracy of our method.

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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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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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