3D elastic full-waveform inversion using P-wave excitation amplitude: Application to ocean bottom cable field data

Oh, Ju‐Won; Kalita, Mahesh; Alkhalifah, Tariq

doi:10.1190/geo2017-0236.1

Cited by 47 publications

(14 citation statements)

References 64 publications

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“…It is a reasonable assumption for practical seismic imaging application, since we always can obtain the smooth background velocity models by the classic migration velocity analysis and tomography. When the inverted P‐wave and S‐wave velocity models with high‐wavenumber components are http://built from elastic full waveform inversion (Petrov and Newman, 2017; Kalita and Alkhalifah, 2017; Oh et al ., 2018; Thiel et al ., 2019), the most efficient and simplest approach to invalidate the assumption is to smooth the velocity models with high‐wavenumber components, prior to the elastic wavefield extrapolation. However, the amount of smoothing required is model dependent.…”

Section: Discussionmentioning

confidence: 99%

“…Multipathing is the concept that seismic energy can travel along various paths between two points (source and receiver), giving rise to multivalued traveltimes (Nguyen and McMechan, 2015). There are many studies in acoustic RTM (Jin et al ., 2015; Kalita and Alkhalifah, 2016), elastic RTM (Du et al ., 2015; Wang and McMechan, 2015) acoustic and elastic full waveform inversion (FWI) (Kalita and Alkhalifah, 2017; Oh et al ., 2018) to demonstrate that the EA imaging condition does not significantly degrade the quality of seismic migration and inversion.…”

Section: Introductionmentioning

confidence: 99%

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2D and 3D amplitude‐preserving elastic reverse time migration based on the vector‐decomposed P‐ and S‐wave records

Zhang

Gao

et al. 2020

Geophysical Prospecting

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The elastic reverse time migration approach based on the vector-wavefield decomposition generally uses the scalar product imaging condition to image the multicomponent seismic data. However, the resulting images contain the crosstalk artefacts and the polarity reversal problems, which are caused by the nonphysical wave modes and the angle-dependent reduction of image amplitudes, respectively. To overcome these two problems, we develop an amplitude-preserving elastic reverse time migration approach based on the vector-decomposed P-and S-wave seismic records. This approach includes two key points. The first is that we employ the vector-decomposed P-and S-wave multicomponent records to independently reconstruct the PP and PS reflection images to mitigate the crosstalk artefacts. The second is that we propose two schemes in addressing the issue of polarity reversal problem in the conventional PP image. One solution is to adopt the angle-dependent equation. Another one is to reconstruct an amplitude-preserving PP image with a separated scalar P-wave particle velocity, which has a clear physical meaning. Numerical examples using two-dimensional and three-dimensional models demonstrate that the proposed elastic reverse time migration approach can provide the images with better amplitude-preserving performance and fewer crosstalk artefacts, compared with the conventional elastic reverse time migration approach based on the scalar product imaging condition.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

2D and 3D amplitude‐preserving elastic reverse time migration based on the vector‐decomposed P‐ and S‐wave records

Zhang

Gao

et al. 2020

Geophysical Prospecting

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“…A simultaneous update scheme for all parameters may suffer from tradeoff issues due to velocity update leakage (Li et al, 2018). Oh et al (2018) used a hierarchical inversion for ocean bottom cable field data. They start their inversion with an acoustic FWI, and gradually include more anisotropic parameters in late stages of the inversion.…”

Section: Discussionmentioning

confidence: 99%

An Efficient Wavefield Inversion for Transversely Isotropic Media with a Vertical Symmetry Axis

Song¹,

Alkhalifah²

2019

81st EAGE Conference and Exhibition 2019

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Conventional full waveform inversion (FWI) aims at retrieving a high-resolution velocity model directly from the wavefields measured at the sensor locations resulting in a highly nonlinear optimization problem. Due to the high nonlinearity of FWI (manifested in one form in the cycle-skipping problem), it is easy to fall into local minima. Considering that the Earth is truly anisotropic, a multi-parameter inversion imposes additional challenges in exacerbating the null-space problem and the parameter tradeoff issue. We formulate an optimization problem to reconstruct the wavefield in an efficient matter with background models by using an enhanced source function (which includes secondary sources) in combination with fitting the data. In this two-term optimization problem to fit the wavefield to the data and to the background wave equation, the inversion for the wavefield is linear. As we keep the modeling operator stationary within each frequency, we only need one matrix inversion per frequency. The inversion for the anisotropic parameters are handled in a separate optimization using the wavefield and the enhanced source function. As velocity is the dominant parameter controlling the wave propagation, it is updated first. Thus, this 1 reduces undesired updates for anisotropic parameters due to the velocity update leakage. We show the effectiveness of this approach in reducing parameter tradeoff with a distinct Gaussian anomaly model. We find that in using the parameterization v h , η, ǫ to describe the VTI model in the inversion, we end up with high resolution and minimal tradeoff compared to conventional parameterizations for the anisotropic Marmousi model. Application on 2D real data also shows the validity of the proposed method.

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“…However, for a huge 3D problem, we need a large number of computational resources to save forward and backward wavefields on every grid point and at every time step. To reduce computational cost, the excitation approach (Kalita and Alkhalifah ; Oh, Kalita and Alkhalifah ) and the boundary‐saving method were suggested, in which we only store the forward wavefields at the model boundary and then we reconstruct the full forward wavefields by back propagating the boundary values (Mitter ; Yang, Gao and Wang ). This approach provided reasonable FWI results for a large‐scale 3D elastic problem (Raknes and Arntsen ; Raknes and Weibull ).…”

Section: Introductionmentioning

confidence: 99%

Study on the full‐waveform inversion strategy for 3D elastic orthorhombic anisotropic media: application to ocean bottom cable data

Alkhalifah

2019

Geophysical Prospecting

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A B S T R A C TThe multi-parameter full waveform inversion is an essential tool to estimate subsurface anisotropic properties in a reservoir that may have complex geological behaviour requiring an elastic orthorhombic medium description. For such elastic orthorhombic media, finding a proper inversion strategy to mitigate parameter trade-off and reduce the Null space is crucial considering the large number of parameters describing the medium. We apply our recently developed strategy for orthorhombic medium inversion on synthetic and real ocean bottom cable data, and find the most efficient inversion strategy. At first, we analyse the trade-off patterns in three elastic orthorhombic parameterizations for a hockey-puck-shaped model. We, then, compare the performance of these orthorhombic parameterizations on a 3D synthetic ocean bottom cable data, which are obtained from a channel-shaped model. By interpreting the inverted models based on analytic radiation patterns of the nine elastic orthorhombic parameters in each parameterization, we observe that parameterizations, which have one P-wave velocity, one S-wave velocity and seven dimensionless parameters, can be optimal to recover subsurface isotropic properties in the early stages of inversion. Then, we show that the choice of three anisotropic parameters and their deviations along the horizontal plane helps us mitigate the complexity of the multi-parameter inversion by decoupling anisotropic features, which have vertical and horizontal symmetric axes, respectively. This decoupling of isotropic and anisotropic properties enables us to perform the multi-parameter anisotropic inversion in a multi-stage manner. In addition, for the marine acquisition, we show that the number of parameters can be reduced from 9 to 4, which makes the multi-parameter inversion more practical. Finally, we apply the elastic orthorhombic inversion to real ocean bottom cable data.

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3D elastic full-waveform inversion using P-wave excitation amplitude: Application to ocean bottom cable field data

Cited by 47 publications

References 64 publications

2D and 3D amplitude‐preserving elastic reverse time migration based on the vector‐decomposed P‐ and S‐wave records

2D and 3D amplitude‐preserving elastic reverse time migration based on the vector‐decomposed P‐ and S‐wave records

An Efficient Wavefield Inversion for Transversely Isotropic Media with a Vertical Symmetry Axis

Study on the full‐waveform inversion strategy for 3D elastic orthorhombic anisotropic media: application to ocean bottom cable data

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