Efficient full waveform inversion using the excitation representation of the source wavefield

Kalita, Mahesh; Alkhalifah, Tariq

doi:10.1093/gji/ggx214

Cited by 28 publications

(26 citation statements)

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“…There are 1824 shot gathers in the original data set at an interval of 0.01875 km, and we choose 100 shot gathers to cover the 2D survey area. The target model we invert for is 12.5 km long and 3.75 km in depth, and the initial velocity model and the estimated wavelet is borrowed from [46], [47], as shown in Figs. 27 and 28, respectively.…”

Section: D Real Datamentioning

confidence: 99%

Efficient Wavefield Inversion With Outer Iterations and Total Variation Constraint

Song

Alkhalifah

2020

IEEE Trans. Geosci. Remote Sensing

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Section: D Real Datamentioning

confidence: 99%

Efficient Wavefield Inversion With Outer Iterations and Total Variation Constraint

Song

Alkhalifah

2020

IEEE Trans. Geosci. Remote Sensing

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“…To ameliorate the computational overburden, we propose to apply the excitation assumption to compute the FWI gradient. This section sheds some light on the excitation method proposed in Kalita and Alkhalifah (2017) followed by its adaption to compute the data misfit gradient of salt-affected seismic dataset.…”

Section: Theorymentioning

confidence: 99%

“…The excitation approach (ExA) utilizes the most energetic part of the source wavefield in order to compute the gradient (Kalita and Alkhalifah, 2017). Most of the energy to the gradient computation is usually extracted from a single scattering optimal (energy wise) path of the waves.…”

Section: Introductionmentioning

confidence: 99%

“…We begin the theory section on FWI with model regularization, which retrieves the sharp edges of the salt body and subsequently, floods it. Next, we report a short review of ExA proposed in Kalita and Alkhalifah (2017), followed by a straightforward extension of ExA to incorporate more than a single arrival in the gradient computation procedure. To demonstrate the versatility of the proposed method, we consider a modified version of the SEG/EAGE salt model, a Ricker wavelet of dominant frequency 5.0 Hz and minimum frequency 3.0 to synthesize the observed seismic data.…”

Section: Introductionmentioning

confidence: 99%

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Regularized full-waveform inversion for large 3-D salt bodies

Kalita

Ghazali

Xin

et al. 2019

SEG Technical Program Expanded Abstracts 2019

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Our objective is to invert for large 3-D salt models using fullwaveform inversion (FWI), especially in the absence of good starting models and low frequencies in the seismic data. This objective incurs a couple of critical issues. First, the presence of salt geobodies aggravates the non-linearity and illposedness of FWI. Second, a 3-D FWI is computationally very expensive, even more so when the initial model is in hindsight very far from the target one. To mitigate the ill-posedness, we propose to utilize model regularization in the FWI framework to promote a limited variation in the inverted model followed by a post-processing step of FWI to penalize sharp velocity drops in the model. Next, to reduce the computational overburden, we propose to utilize a multi-excitation assumption (MExA) of source wavefields in the FWI gradient calculation step. This assumption, due to the simplistic nature of the source wavelet, approximates the source wavefield wiggle at a gridpoint by a series of its energetic arrivals. As a result, the gradient evaluation using MExA requires us neither to store the entire source wavefield nor to include an additional extrapolation step to propagate the source wavefield from its temporary storage at the boundary. The versatility of the proposed method is demonstrated on a synthetic dataset of the modified SEG/EAGE salt model in which the lowest available frequency is 3 Hz.

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“…The target model area we choose is 12.5 km long and 3.75 km in depth. The initial horizontal velocity model is borrowed from (Kalita andAlkhalifah, 2017, 2018), as shown in Figures 2. We resample the data and use 324 receivers, with an interval of 0.025 km.…”

Section: Examplesmentioning

confidence: 99%

Efficient wavefield inversion in acoustic VTI media applied to field data

Song

Alkhalifah

2019

SEG Technical Program Expanded Abstracts 2019

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Full-waveform inversion (FWI) is now often used to retrieve high-resolution velocity models in marine datasets. Directly matching the predicted data with the recorded ones at the sensor locations, results in a highly nonlinear optimization problem. Besides its inherent high nonlinearity (manifested in one form in the cycle-skipping problem), considering the anisotropic reality of the true Earth, a multi-parameter inversion imposes additional Null space and the tradeoff issues. To solve these problems, we formulate an optimization problem referred to as an efficient wavefield inversion (EWI) to retrieve multi-parameters. EWI uses background models to reconstruct the wavefield efficiently by introducing an enhanced source function (which includes secondary sources). In this setup, the inversion for the wavefield is linear and efficient. The anisotropic parameters are inverted in a separate direct optimization using the wavefield and the enhanced source function in an efficient matter (no modeling involved). We demonstrate the effectiveness of the proposed method on an Australian marine real data, and compare inverted results with check shot velocity information from a well.

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Efficient full waveform inversion using the excitation representation of the source wavefield

Abstract: CitationKalita M, Alkhalifah T (2017) Efficient full waveform inversion using the excitation representation of the source wavefield. Geophysical Journal International 210: 1581-1594. Available:

Cited by 28 publications

References 50 publications

Efficient Wavefield Inversion With Outer Iterations and Total Variation Constraint

Efficient Wavefield Inversion With Outer Iterations and Total Variation Constraint

Regularized full-waveform inversion for large 3-D salt bodies

Efficient wavefield inversion in acoustic VTI media applied to field data

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