A unique solution for acquiring near offsets

TopSeis™ is a next-generation marine towed-streamer acquisition solution, delivering a step-change in imaging for shallow to intermediate depth targets by providing massively increased near-offset coverage from a split spread with zero offsets. It is the latest addition to our broadband portfolio and is the most recent outcome from over eight years of technical collaboration between CGG and Lundin Norway AS.

TopSeis is a tailored solution, specifically designed to improve imaging of shallow and intermediate-depth targets by overcoming the lack of near-offset fold inherent in towed-streamer seismic. TopSeis achieves this by using an innovative source-over-spread acquisition configuration and proprietary processing algorithms.

TopSeis VS BroadSeis Spread

Based on an original idea from Lundin, TopSeis has been developed over the last two years by a multi-disciplinary team of CGG and Sercel Equipment, Marine Acquisition and Geoscience experts, using synthetic data and field trials to derive optimum configurations for specific targets and to develop methods to deploy these configurations safely. It capitalizes on CGG’s long-standing broadband capabilities, including deep-tow experience from acquiring over 350,000 km² of BroadSeis™, deployment of our broadband source (BroadSource™) and our recognized Subsurface Imaging excellence. 

Both a 2D and 3D pilot survey have been conducted and TopSeis is now a commercially-ready solution with the first commercial survey planned for the Barents Sea with Lundin’s support in 2017.


  • High fold with increased near-offset coverage
  • High resolution
  • Dense crossline separation
  • Zero offsets
  • Crossline offsets
  • Full azimuth at near offsets
TopSeis vessels


  • Enhanced imaging of shallow and intermediate reservoirs in water depths deeper than 100 m
  • Better S/N from increased fold
  • Improved AVO from increased fold and recorded zero-offset data
  • Considerably lower-cost solution than OBS
  • Anticipated better multiple attenuation from increased near-offset coverage

Synthetic Model AVO studies

The significantly increased sampling of near and zero offsets delivered by TopSeis should result in improved AVO curve fitting as well as direct recording of the intercept, R0. This will increase the accuracy and reliability of the AVO results.
Synthetic ComparisonFor a synthetic model, based on the Wisting field in the Barents Sea, and developed in collaboration with OMV, the TopSeis response to the model can be seen to deliver a much better correlation for the AVO intercept and gradient than the conventional response. The TopSeis synthetic seismic also shows much better correlation with the model, with sharper wavelets, less noise and a clearer oil water contact.

AVO Intercept - Zero Offset Reflectivity


Slide the image to see the difference.

AVO Gradient


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Field Trial

A 15km x 3km 3D trial was carried out over the Frigg-Gamma field in the North Sea. The multi-client BroadSeis data was used as the reference. The TopSeis data shows considerable improvement over the reference data, especially where illuminated by the outer streamers only. Processing of this data is still ongoing but initial results are shown below.


Slide the image to see the difference.

The improvement continues deeper in the section, as seen in the comparison below
deeper comparison

Offshore - Broadband Toolbox

Broadband Solutions

Flexibility is the key to a successful project. CGG offers a toolbox of broadband solutions to help you acquire the data you want.

Offshore - BroadSource


A fully proven broadband source, compatible with all receiver deghosting technology for ghost-free broadband data.
Offshore - GeoHazards

Solutions for Geohazards

Clear, high-resolution near-surface images to delineate the smallest structures. Over 6 octaves of data from BroadSource for shallow hazard identification.
Multi-Client Data - Barents Sea

Barents Sea

See play models at different levels, from the Triassic/Jurassic, through Carboniferous/Permian to the Devonian/Carboniferous with BroadSeis data in the Barents Sea
Offshore - Tailored Acquisition Solutions

Tailored Acquisition Solutions

Acquisition tailored to your geological challenges, time or budgetary constraints. Innovative spread designs and imaging solutions for complex geologies or time-limited or difficult access.
Offshore - Assets and Technologies

Marine Assets and Technologies

Our high-end fleet is complemented by advanced technologies and our experienced people who go the extra mile to get to get the job done
Offshore (Marine)


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Technical Abstracts


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September 24 - 29, 2017
87th SEG Annual Meeting 2017
Houston, United States

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September 25 - 26, 2017
West and Central Africa (WaCA...
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September 27 - 28, 2017
West Texas Geological Society...
Midland, United States

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