Broadband processing of linear streamer data

Masoomzadeh, Hassan; Woodburn, N.; Hardwick, Anthony

doi:10.1190/segam2013-0872.1

Cited by 24 publications

(5 citation statements)

References 2 publications

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“…The authors do not attempt the estimation of the reflection coefficient. Masoomzadeh et al (2013) point out that de-ghosting errors can be reduced by using a stochastic search for the optimum set of de-ghosting parameters that includes both delay-times and reflection coefficients that can vary with frequency. However, the search criteria or, in other words the objective function for the parameters optimisation, is not mentioned.…”

Section: Adaptive De-ghosting By Kurtosis Maximisationmentioning

confidence: 99%

Adaptive De-ghosting by Kurtosis Maximisation

Grion¹,

Telling²,

Barnes³

2015

Proceedings

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We discuss the reasons for adaptive de-ghosting and its advantages. The success of broadband processing relies on de-ghosting accuracy, and because the parameters of the physical process determining the ghost reflection are not precisely known, de-ghosting cannot be purely deterministic. The physical entities determining the receiver ghost are the sea surface, the receiver depth and the water velocity and for de-ghosting purposes they can be represented by an effective ghost delay-time and sea surface reflection coefficient. The de-ghosting optimisation metric we employ is based on the kurtosis of the data-autocorrelation. The kurtosis is a statistical measure often used to associate a measure of "peakedness" to a random variable. A synthetic example characterizes the main features of the adaptive procedure proposed, which can be sequenced in two steps. The optimisation of the ghost delay-time is robust to errors in the reflection coefficient and to noise, Therefore, it should be performed first. The reflection coefficient estimate is more sensitive to noise and requires the delaytime to be optimized in advance, and can therefore be carried out as a second step. A real data example demonstrates the applicabilityof the proposed method.

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Section: Adaptive De-ghosting By Kurtosis Maximisationmentioning

confidence: 99%

Adaptive De-ghosting by Kurtosis Maximisation

Grion¹,

Telling²,

Barnes³

2015

Proceedings

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show abstract

“…Compared to traditional 'narrowband' seismic processing, 'broadband' processing aims to improve the spectral accuracy by expanding the data bandwidth and restoring frequency content attenuated by the source-and receiverside 'ghost' effect and by seismic absorption (Masoomzadeh et al 2013;Lille et al 2017). High frequencies are most strongly affected by seismic absorption, which preferentially attenuates the highest frequency parts of the spectrum (Futterman 1962;Sams et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Reprocessing 2-D airgun seismic reflection data SALTFLU (salt deformation and sub-salt fluid circulation in the Algero-Balearic abyssal plain) in the Balearic promontory and the Algerian basin

Blondel

Ford

Lockwood³

et al. 2023

Mar Geophys Res

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In an ever more challenging context for the acquisition of seismic data in the Mediterranean Sea, reprocessing to improve the quality of legacy data has become increasingly important. This work presents the newly reprocessed, open access dataset SALTFLU acquired in the Algerian basin by the National Institute of Oceanography and Applied Geophysics (OGS) in 2012. We apply a ‘broadband’ reprocessing strategy adapted for offset-limited (3 km streamer for a target 4 km below the sea level) airgun reflection seismic data acquired in deep water settings. We then assess if the reprocessed images provide new geological insights on the Mediterranean sub-surface. The workflow relies on an integrated approach combining geophysics and geological interpretation to iteratively build the velocity model. In this way we aim to tackle some of the challenges linked to imaging deep complex geological structures containing high velocity contrasts with 2-D, offset-limited seismic data. We first broaden the bandwidth of the data through multi-domain de-noising, deghosting and a source designature using an operator derived from the seabed reflection. We then perform iterative migration velocity analysis, pre-stack time migration and multiple attenuation in the Radon domain to obtain time-migrated images. The initial velocity model is derived from the resulting time migration velocities, and geologically driven model updates are generated using a combination of travel-time tomography, seismic interpretation of the major salt horizons and velocity gradient flooding. The gradient flooding aims to reproduce the large scale first-order velocity variations, while the travel-time tomography aims to resolve the smaller second-order velocity variations. The results improve our deep geological knowledge of the under-explored Algerian basin down to the base salt and the pre-salt. Fluid indicators are imaged within the Plio-Quaternary of the Algerian basin, which we interpret as thermogenic or biogenic gas sourced from either the Messinian Upper Unit or from the pre-salt, migrating through a hydro-fractured salt. The reprocessed data image lateral and vertical seismic facies variation within the Messinian units that could shed new light on the tectono-stratigraphic processes acting during the Messinian Salinity Crisis. It also reveals numerous previously unresolved volcanic structures within the Formentera basin.

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“…Compared to traditional 'narrowband' seismic processing, 'broadband' processing aims to improve the spectral accuracy by expanding the data bandwidth and restoring frequency content attenuated by the source-and receiver-side 'ghost' effect and by seismic absorption (Masoomzadeh et al, 2013;Lille et al, 2017). High frequencies are most strongly affected by seismic absorption, which preferentially attenuates the highest frequency parts of the spectrum (Futterman, 1962;Sams et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Reprocessing 2-D Airgun Seismic Reflection Data SALTFLU (Salt Deformation And Sub-Salt Fluid Circulation In The Algero-Balearic Abyssal Plain) In the Balearic Promontory and the Algerian Basin

Blondel

Ford

Lockwood

et al. 2022

Preprint

View full text Add to dashboard Cite

In an ever more challenging context for the acquisition of seismic data in the Mediterranean Sea, reprocessing to improve the quality of legacy data has become increasingly important. This work presents the newly reprocessed, open access dataset SALTFLU acquired in the Algerian basin by the National Institute of Oceanography and Applied Geophysics (OGS) in 2012. We apply a ‘broadband’ reprocessing strategy adapted for offset-limited (3km streamer for a target 4 km below the sea level) airgun reflection seismic data acquired in deep water settings. We then assess if the reprocessed images provide new geological insights on the Mediterranean sub-surface. The workflow relies on an integrated approach combining geophysics and geological interpretation to iteratively build the velocity model. In this way we aim to tackle some of the challenges linked to imaging deep complex geological structures containing high velocity contrasts with 2-D, offset-limited seismic data. We first broaden the bandwidth of the data through multi-domain de-noising, deghosting and a source designature using an operator derived from the seabed reflection. We then perform iterative migration velocity analysis, pre-stack time migration and multiple attenuation in the Radon domain to obtain time-migrated images. The initial velocity model is derived from the resulting time migration velocities, and geologically driven model updates are generated using a combination of travel-time tomography, seismic interpretation of the major salt horizons and velocity gradient flooding. The gradient flooding aims to reproduce the large scale first-order velocity variations, while the travel-time tomography aims to resolve the smaller second-order velocity variations. The results improve our deep geological knowledge of the under-explored Algerian basin down to the base salt and the pre-salt. Fluid indicators are imaged within the Plio-Quaternary of the Algerian basin, which we interpret as thermogenic or biogenic gas sourced from either the Messinian Upper Unit or from the pre-salt, migrating through a hydro-fractured salt. The reprocessed data image lateral and vertical seismic facies variation within the Messinian units that could shed new light on the tectono-stratigraphic processes acting during the Messinian Salinity Crisis. It also reveals numerous previously unresolved volcanic structures within the Formentera basin.

show abstract

Broadband processing of linear streamer data

Cited by 24 publications

References 2 publications

Adaptive De-ghosting by Kurtosis Maximisation

Adaptive De-ghosting by Kurtosis Maximisation

Reprocessing 2-D airgun seismic reflection data SALTFLU (salt deformation and sub-salt fluid circulation in the Algero-Balearic abyssal plain) in the Balearic promontory and the Algerian basin

Reprocessing 2-D Airgun Seismic Reflection Data SALTFLU (Salt Deformation And Sub-Salt Fluid Circulation In The Algero-Balearic Abyssal Plain) In the Balearic Promontory and the Algerian Basin

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