Ocean Bottom Seismographs (OBS) are relatively commonly used in scientific lithospheric investigations in many parts of the world. On the Norwegian continental shelf several investigations of this kind have been performed during the last eight years as a result of the fruitful cooperation between the Institute of Solid Earth Physics, University of Bergen, the Laboratory for Ocean Bottom Seismology, Hokkaido University, the Laboratory for Earthquake Chemistry, Tokyo University, and Statoil.

Seismometer

Marine geology

Norwegian

Ocean bottom

10.3997/1365-2397.1996012

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Citations (14)

Air‐gun bubble damping by a screen

Geophysics (1995)

Jan Langhammer Martin Landrø James E. Martin E. Berg

A method for damping unwanted bubble oscillations from a seismic air gun is presented. The method exploits the fact that the primary pressure peak generated by an air gun is produced during the first 5–10 ms after firing. The air bubble is destroyed by mounting a perforated screen with an optimal radius about the gun. Once the primary pressure peak has been generated by the bubble, the bubble is destroyed by the screen, leading to a corresponding decrease in the measured pressure amplitude of the secondary bubble oscillations. Controlled near‐field measurements of 40‐cubic inch and 120‐cubic inch air guns with and without damping screens are used. The primary to bubble ratio improves from 1.4 without a screen to 4.4 with a screen in the near‐field. The corresponding values for estimated far‐field signatures are 1.8 to 9.0 when the signatures are filtered with an out‐128 Hz (72 dB/Oct) DFS V filter.

Air bubble

10.1190/1.1443910

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Citations (8)

Emerging Geophysical Technologies: Is Planting and Re-Planting of Nodes in a 4C-4D Scenario the Optimum and Most Cost-Effective Solution for Field Reservoir Monitoring?

All Days (2008)

E. Berg C. Vuillermoz Geir Woje Gunnar Ekmann

Abstract Seabed data acquisition methods offer numerous advantages over towed streamer data. These advantages can lead to improved static and dynamic reservoir characterization. By recording complete vector field data at the sea floor with full azimuth acquisition improved shallow resolution, signal-to-noise ratio, spectral content, deep imaging and 3D illumination can be achieved. Also in the presence of obstacles such as production facilities a regular coverage can be assured. Autonomous node technology has been developed to a fully commercial system. It has demonstrated improved imaging of complex reservoir with both pressure (PP) and converted shear (PS) with stable and consistent measurements achieved by very well planted nodes into the sea floor and full azimuth acquisition with densely sampled shots. It has been experienced that the background response from well planted nodes can be repeated in a 4C-4D scenario when the coupling conditions are the same. The vector fidelity in the node system will secure this behavior. In addition, the accurate positioning and re-positioning of the nodes under realistic water depth ranges gives positioning accuracy close to permanently buried cable systems. An experiment performed on the Volve field in the North Sea with pairs of nodes planted side by side clearly confirmed the high degree of stability in the coupling and the repeatability of the measurements from all components. At 100 m water depth all the planted nodes were within a short radius around the pre-plot position. A cost sensitivity study of different 4C-4D node scenarios depending of field size, water depths and node spacing indicates that, for larger field sizes (300-600km2 receiver coverage), the alternative use of nodes could be significantly more cost effective than permanently buried cable systems. Moreover, there are advantages linked to the acquisition geometry, operation, zero equipment life time risk and low initial investment. Introduction Marine seismic exploration and reservoir imaging have been through numerous stages of adjustments and improvements. Towed streamer surveys from 2D to 3D and now to 4D dominate the offshore seismic survey with a well established technology which remains the most common acquisition with narrow azimuth coverage. New techniques such as " single sensor recording?? (Egan et al, 2005), " over-under?? (Singh et al, 1996) and " wide azimuth?? (Campbell et al, 2002) have recently delivered impressive results. These techniques have raised the cost and complexity to more traditionally " simple?? towed streamer operations.

Seabed

10.4043/19691-ms

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Citations (5)

Emerging Geophysical Technologies: Is Planting and Re-planting of Nodes in a 4C-4D Scenario the Optimum and Most Cost-Effective Solution for Field Reservoir Monitoring?

Proceedings of Offshore Technology Conference (2007)

E. Berg C. Vuillermoz Geir Woje Gunnar Ekmann

Seabed data acquisition methods offer numerous advantages over towed streamer data. These advantages can lead to improved static and dynamic reservoir characterization. By recording complete vector field data at the sea floor with full azimuth acquisition improved shallow resolution, signal-to-noise ratio, spectral content, deep imaging and 3D illumination can be achieved. Also in the presence of obstacles such as production facilities a regular coverage can be assured.Autonomous node technology has been developed to a fully commercial system. It has demonstrated improved imaging of complex reservoir with both pressure (PP) and converted shear (PS) with stable and consistent measurements achieved by very well planted nodes into the sea floor and full azimuth acquisition with densely sampled shots.It has been experienced that the background response from well planted nodes can be repeated in a 4C-4D scenario when the coupling conditions are the same. The vector fidelity in the node system will secure this behavior. In addition, the accurate positioning and re-positioning of the nodes under realistic water depth ranges gives positioning accuracy close to permanently buried cable systems. An experiment performed on the Volve field in the North Sea with pairs of nodes planted side by side clearly confirmed the high degree of stability in the coupling and the repeatability of the measurements from all components. At 100 m water depth all the planted nodes were within a short radius around the pre-plot position.A cost sensitivity study of different 4C-4D node scenarios depending of field size, water depths and node spacing indicates that, for larger field sizes (300-600km2 receiver coverage), the alternative use of nodes could be significantly more cost effective than permanently buried cable systems. Moreover, there are advantages linked to the acquisition geometry, operation, zero equipment life time risk and low initial investment.Introduction. Marine seismic exploration and reservoir imaging have been through numerous stages of adjustments and improvements. Towed streamer surveys from 2D to 3D and now to 4D dominate the offshore seismic survey with a well established technology which remains the most common acquisition with narrow azimuth coverage. New techniques such as

Seabed

10.2118/19691-ms

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Citations (1)

Vector Fidelity Analyses of Seabed Seismic Data

Geir Woje E. Berg J.I. Rykkelid Ø. Svendsen O. Aanensen

E-03 VECTOR FIDELITY ANALYSES OF SEABED SEISMIC DATA GEIR WOJE EIVIND BERG JON IVAR RYKKELID ØYSTEIN SVENDSEN Abstract 1 The vector fidelity analyses are performed on the first break of three different data sets. RMS mapping modelling polarization analyses and frequency analyses all prove to differentiate the sensors with respect to vector fidelity. One cable sensor and three planted sensors (nodes) are evaluated. There are significant differences between the cable sensor and the planted nodes. The results suggest that cable sensors are not qualified for wide azimuth acquisitions. Introduction During the last years vector fidelity has become a major subject

High fidelity

Seabed

10.3997/2214-4609-pdb.5.e003

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Citations (4)

“Node‐based sea‐bottom seismic, a new way to reservoir management”

C. Pettenati‐Auziere C. Debouvry E. Berg

PreviousNext No AccessSEG Technical Program Expanded Abstracts 1997"Node‐based sea‐bottom seismic, a new way to reservoir management"Authors: C. Pettenati‐AuziereC. DebouvryE. BergC. Pettenati‐AuziereCompagnie Générale de Geophysique, C. DebouvryCompagnie Générale de Geophysique, and E. BergSubseacohttps://doi.org/10.1190/1.1886111 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Permalink: https://doi.org/10.1190/1.1886111FiguresReferencesRelatedDetailsCited ByGeophone orientation and coupling in three-component sea-floor data: a case studyGeophysical Prospecting, Vol. 47, No. 6 SEG Technical Program Expanded Abstracts 1997ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 1997 Pages: 2067 publication data© 1997 Copyright © 1997 Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished: 10 Feb 2005 CITATION INFORMATION C. Pettenati‐Auziere, C. Debouvry, and E. Berg, (1997), ""Node‐based sea‐bottom seismic, a new way to reservoir management"," SEG Technical Program Expanded Abstracts : 71-74. https://doi.org/10.1190/1.1886111 Plain-Language Summary PDF DownloadLoading ...

Ocean bottom

10.1190/1.1886111

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Citations (3)

Three-component OBS-data processing for lithology and fluid prediction in the mid-Norway margin, NE Atlantic

Earth Planets and Space (2014)

E. Berg Lasse Amundsen Andrew Morton Rolf Mjelde Hideki Shimamura

In 1992, acomprehensive three-component ocean bottom seismic survey was performed in the central and northern area of the Vøring Basin, offshore mid-Norway, NE Atlantic. An important part of the data acquisition program consisted of a local survey with 20 Ocean Bottom Seismographs (OBS) dropped at approximately 200 m interval in 1300 m water depth. The main purpose of the local survey was to acquire densely sampled P- and S-wave reflection data above a seismic flatspot anomaly observed earlier, in order to more accurately predict if hydrocarbons could be related to it. The conventional reflection data processing methods applied to the vertical components included predictive deconvolution in order to attenuate low frequency ringing, near offset mute and a series of constant velocity stacks in order to obtain the optimal velocity function. The final result is a "trouser" shaped, high resolution VZ stacked section with minor influence of water multiples. The inline (Vx ) component contains no strong multiples, and extensive near trace muting was hence not necessary to apply for this component. Velocity analysis together with ray-tracing modelling indicate that P-S-converted shear waves (reflections) represent the dominant mode. The results of the interpretation and modelling indicated a Vp/Vs-ratio of approximately 2.6 in the overburden, which suggests domination of partly unconsolidated shale, while the Vp/Vs-ratio in the assumed reservoir was approximately 1.8, which indicates a more sand dominated facies. Outside the flatspot area a higher Vp/Vs-ratio ratio (approximately 2.0) was estimated, indicating that hydrocarbons could be present in the assumed reservoir.

Margin (machine learning)

Component (thermodynamics)

Lithology

10.1186/bf03352365

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Citations (5)

Crustal Transect Across the Lofoten Margin, Northern Norway, Obtained by Use of Ocean Bottom Seismographs

Proceedings (1995)

Shuichi Kodaira Rolf Mjelde Markvard A. Sellevoll H. B. Hirschleber Hideki Shimamura

The continental break-up between Norway and Greenland occurred in late Paleocene / early Eocene, and was associated with an intensive volcanisim along the margin. At a passive continental margin the whole process of crustal evolution is generally retained in the crustal structure from the continent to the ocean.

Seismometer

Continental Margin

Margin (machine learning)

Passive margin

10.3997/2214-4609.201409544

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Citations (0)

Maximum‐likelihood estimation of reflection coefficients from seismic data: A case study

Ivar Brevik E. Berg

PreviousNext No AccessSEG Technical Program Expanded Abstracts 1986Maximum‐likelihood estimation of reflection coefficients from seismic data: A case studyAuthors: I. BrevikE. W. BergI. BrevikContinental Shelf and Petroleum Technology Research Institute Ltd., Norway and E. W. BergContinental Shelf and Petroleum Technology Research Institute Ltd., Norwayhttps://doi.org/10.1190/1.1893130 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Permalink: https://doi.org/10.1190/1.1893130FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 1986ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 1986 Pages: 715 publication data© 1986 Copyright © 1986 Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 07 Mar 2005 CITATION INFORMATION I. Brevik and E. W. Berg, (1986), "Maximum‐likelihood estimation of reflection coefficients from seismic data: A case study," SEG Technical Program Expanded Abstracts : 273-277. https://doi.org/10.1190/1.1893130 Plain-Language Summary PDF DownloadLoading ...

Reflection

10.1190/1.1893130

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Citations (1)