Moveout analysis by time‐warping

Burnett, William; Fomel, Sergey

doi:10.1190/1.3255639

Cited by 19 publications

(7 citation statements)

References 20 publications

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“…Predicted TWTT curve is obtained using the fact that TWTTs with the same zero-offset TWTT belong to the same wavefront. The procedure of predicting TWTT curves from the predicted zero-offset TWTTs is known as time warping (Burnett and Fomel, 2009b). The standard error around the exact curve is less than 0.1% in this example.…”

Section: Application To a Synthetic Data Examplementioning

confidence: 98%

Velocity-independent estimation of kinematic attributes in vertical transverse isotropy media using local slopes and predictive painting

2016

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Agood seismic velocity model is required for many routine seismic imaging techniques. Velocity model building from seismic data is often labor intensive and time consuming. The process becomes more complicated by taking nonhyperbolic traveltime estimations into account. An alternative to the conventional time-domain imaging algorithms is to use techniques based on the local event slopes, which contain sufficient information about the traveltime moveout for velocity estimation and characterization of the subsurface geologic structures. Given the local slopes, there is no need for a prior knowledge of a velocity model. That is why the term "velocity independent" is commonly used for such techniques. We improved upon and simplified the previous versions of velocity-independent nonhyperbolic approximations for horizontally layered vertical transverse isotropy (VTI) media by removing one order of differentiation with respect to offset from the imaging kinematic attributes. These kinematic attributes are derived in terms of the local event slopes and zero-offset two-way traveltime (TWTT). We proposed the use of predictive painting, which keeps all the attributes curvature independent, to estimate the zero-offset TWTT. The theoretical contents and performance of the proposed approach were evaluated on synthetic and field data examples. We also studied the accuracy of moveout attributes for shifted hyperbola, rational, three-parameter, and acceleration approximations on a synthetic example. Our results show that regardless of the approximation types, NMO velocity estimate has higher accuracy than the nonhyperbolicity attribute. Computational time and accuracy of the inversion of kinematic attributes in VTI media using our approach were compared with routine/conventional multiparameter semblance inversion and with the previous velocityindependent inversion techniques.

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Section: Application To a Synthetic Data Examplementioning

confidence: 98%

Velocity-independent estimation of kinematic attributes in vertical transverse isotropy media using local slopes and predictive painting

2016

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“…In this case, multiparameter moveout semblance analysis, predictive painting (Fomel, 2010), and time warping (Burnett and Fomel, 2009) are alternatives for extracting the traveltime residuals. The WT algorithm might be a useful tool for building complex velocity models, especially for subsalt structures and with strong lateral gradients.…”

Section: Discussionmentioning

confidence: 99%

Shot- and angle-domain wave-equation traveltime inversion of reflection data: Theory

2015

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The main difficulty with iterative waveform inversion is that it tends to get stuck in local minima associated with the waveform misfit function. To mitigate this problem and avoid the need to fit amplitudes in the data, we have developed a wave-equation method that inverts the traveltimes of reflection events, and so it is less prone to the local minima problem. Instead of a waveform misfit function, the penalty function was a crosscorrelation of the downgoing direct wave and the upgoing reflection wave at the trial image point. The time lag, which maximized the crosscorrelation amplitude, represented the reflection-traveltime residual (RTR) that was back projected along the reflection wavepath to update the velocity. Shot-and angle-domain crosscorrelation functions were introduced to estimate the RTR by semblance analysis and scanning. In theory, only the traveltime information was inverted and there was no need to precisely fit the amplitudes or assume a high-frequency approximation. Results with synthetic data and field records revealed the benefits and limitations of wave-equation reflection traveltime inversion.

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“…For complex models with short-wavelength errors, the semblance analysis based on a single parameter moveout equation does not ensure a precise representation of traveltime residuals. In this case, multiparameter moveout semblance analysis, predictive painting (Fomel, 2010), and time warping (Burnett and Fomel, 2009) extracting the traveltime residuals. This is a subject for future research.…”

Section: Discussionmentioning

confidence: 99%

Shot- and angle-domain wave-equation traveltime inversion of reflection data: Synthetic and field data examples

2015

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Full-waveform inversion requires the accurate simulation of the dynamics and kinematics of wave propagation. This is difficult in practice because the amplitudes cannot be precisely reproduced for seismic waves in the earth. Waveequation reflection traveltime tomography (WT) is proposed to avoid this problem by directly inverting the reflectiontraveltime residuals without the use of the high-frequency approximation. We inverted synthetic traces and recorded seismic data for the velocity model by WT. Our results demonstrated that the wave-equation solution overcame the high-frequency approximation of ray-based tomography, was largely insensitive to the accurate modeling of amplitudes, and mitigated problems with ambiguous event identification. The synthetic examples illustrated the effectiveness of the WT method in providing a highly resolved estimate of the velocity model. A real data example from the Gulf of Mexico demonstrated these benefits of WT, but also found the limitations in traveltime residual estimation for complex models.

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Moveout analysis by time‐warping

Cited by 19 publications

References 20 publications

Velocity-independent estimation of kinematic attributes in vertical transverse isotropy media using local slopes and predictive painting

Velocity-independent estimation of kinematic attributes in vertical transverse isotropy media using local slopes and predictive painting

Shot- and angle-domain wave-equation traveltime inversion of reflection data: Theory

Shot- and angle-domain wave-equation traveltime inversion of reflection data: Synthetic and field data examples

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