CGG has provided further details about the seismic data study performed by its integrated geosciences Northern Viking Graben solution, which covered around 36,000km² in the offshore regions of Norway and the UK.
The study encompasses combining broadband seismic data with geology, well data and reservoir characterisation that help identify new prospects in the area. Northern North Sea already hosts large discoveries such as Troll, Statfjord and Brage.
The Northern Viking Graben multi-client broadband seismic survey was conducted using CGG’s full-bandwidth BroadSeis-BroadSource solution.
The high-resolution seismic data covered the stretch of North Sea between Norway and the UK. Procured gravity data has been used to define the basement depth.
Broadband seismic data is an essential part of the integrated study that encompasses regional well correlation, prospectivity reviews, seep studies from geochemistry and satellite imagery, sedimentological and petrophysical analyses, gravity data, as well as seismic reservoir characterisation.
The study enriches existing seismic data of 50 wells which were re-evaluated, tied and calibrated to the seismic. Well data has come from a variety of sources that comprises edited petrophysical logs, well-to-seismic calibrations and sedimentary descriptions of core, among others.
Extensive quality control is performed on all data before correlating and analysing it against the seismic readings.
To avoid discrepancies, well-to-seismic calibration was performed with careful assessment of wavelet character at the well location, as well as the quality of wireline used for synthetics and its general condition.
Results were applied to the reanalysis of biostratigraphic data, which was then used to review the lithostratigraphy and increase accuracy of formation tops. These well results with the broadband seismic data were mapped across the entire survey.
CGG also accomplished 3D AVO attribute generation and 3D deterministic acoustic inversion for two projects that total nearly 3,200km² over the Ryggstein Ridge and Måløy Slope.
Reservoir characterisation projects and integrated studies will be broadened to the entire Northern Viking Graben survey that will provide a complete understanding of petroleum systems in the Northern North Sea and locate new prospects.
Once complete, the studies will help to reduce the uncertainty when attempting to understand petroleum systems.
Image: Acoustic Impedance crossline over the Skarfjell structure. Photo: courtesy of CGG.