Seismic Imaging with Ocean-Bottom Nodes (OBN): Mirror Migration Technique

Pacal, E.; Stewart, Robert R.; Baysal, Edip; Yılmaz, Orhan

doi:10.1190/segam2015-5886915.1

Cited by 8 publications

(2 citation statements)

References 13 publications

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“…The Figures 1, 2 and 3 highlights the ghost and the peg-leg events as the dashed lines and vectors because those are considered as noises that compound the first order multiples in the sea-floor seismic data, when we follow the upgoing wavefield processing strategy, on which was focused this search. For downgoing wavefield processing strategy, the ghost is separated into the downgoing wavefield and it is considered as signal to accomplish the called mirror migration (Pacal et al, 2015).…”

Section: The Measured Wavefieldsmentioning

confidence: 99%

Robust filtering of ghost and peg-leg from sea floor seismic data

Alves

Oliveira

2023

Braz J Geophys

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ABSTRACT. The processing of compressional waves from the acoustic components of ocean bottom seismic data is performed decomposing the compressional wavefield on its upgoing an downgoing components, treating the first order multiples, composed by the overlap between the receiver ghost and peg-leg. The separation of these wavefields is achieved through the adaptive summation of the hydrophone and geophone components, usually on a least square sense. This method of separation is known as PZ summation, because it involves an operation between pressure and vertical particle velocity measurements. However, due to the difference in response of the pressure and velocity sensors, the premises assumed on the least square summation can be violated, degrading the results. To overcome these difficulties, a more robust method can be achieved using the L1 norm criterion for the adaptive sum. A comparison was made between the results obtained with the Iterative Reweighted Least Squares and Wiener-Levinson filters. The robustness of the L1 norm sum was demonstrated by applications on PZ summation of Ocean Bottom Cable data from the Jubarte area, in the Campos Basin, Brazil, showing improvements, especially when the multiples are present in the estimation window used to derive the filter coefficients.

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Section: The Measured Wavefieldsmentioning

confidence: 99%

Robust filtering of ghost and peg-leg from sea floor seismic data

Alves

Oliveira

2023

Braz J Geophys

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“…Realizing the accurate imaging of the seabed and underlying shallow strata is the premise of multiple prediction using the demigration technology. To image the seabed and underlying shallow strata, Pacal et al (2015) proposed a mirror migration method using downgoing waves (ghost or first-order multiples reflected from the sea surface). The results show that its imaging effect is significantly better than the traditional migration method using the primary wave.…”

Section: Kirchhoff Pre-stack Mirror Migration Based On Downgoing Wavementioning

confidence: 99%

Surface‐related multiple prediction for ocean‐bottom node data based on demigration using downgoing wave imaging data

Tan

Wang

Song

et al. 2023

Geophysical Prospecting

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Ocean‐bottom node exploration has developed rapidly in marine seismic exploration. However, due to no illumination for the seafloor, and the observation system of the ‘less traces but more shots’ mode, the conventional surface‐related multiples elimination meets challenges for the application in the ocean‐bottom node exploration. This paper develops a new three‐dimensional surface‐related multiples elimination technique for ocean‐bottom node data. First, a three‐dimensional Kirchhoff pre‐stack time mirror migration algorithm is proposed to realize the accurate imaging for the seabed. Second, the time domain Kirchhoff demigration method is used to construct the contribution traces for multiples prediction. Finally, the surface multiples can be predicted based on the equation derived in the paper. Model tests and field data processing prove that our method can accurately predict the surface‐related multiples for ocean‐bottom node data and be helpful to the multiple elimination, which shows that the proposed technique has potential in actual ocean‐bottom node data processing.

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Joint inversion of the reflectivity and the velocity model

et al. 2021

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During linearized waveform inversion, the presence of small inaccuracies in the background subsurface model can lead to unfocused seismic events in the final image. The effect on the amplitude can mislead the interpretation. We present a joint inversion scheme in the model domain of the reflectivity and the background velocity model. The idea is to unify the inversion of the background and the reflectivity model into a single framework instead of treating them as decoupled problems. We show that with this method, we can obtain a better estimate of the reflectivity than that obtained with conventional linearized waveform inversion. Conversely, the background model is improved by the joint inversion with the reflectivity in comparison with wave-equation migration velocity analysis. We perform tests on 2D synthetics and 3D field data that demonstrate both benefits.

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Seismic Imaging with Ocean-Bottom Nodes (OBN): Mirror Migration Technique

Cited by 8 publications

References 13 publications

Robust filtering of ghost and peg-leg from sea floor seismic data

Robust filtering of ghost and peg-leg from sea floor seismic data

Surface‐related multiple prediction for ocean‐bottom node data based on demigration using downgoing wave imaging data

Joint inversion of the reflectivity and the velocity model

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