Faced with a series of technical challenges to provide better imaging of pre-salt section beneath steep-sided salt features, Wintershall Noordzee B.V. and partners contracted PGS Geophysical to use innovative multi-azimuth technology for the acquisition of 3D seismic data. The survey over Block L5b of the Dutch North Sea involved acquiring data in two orthogonal directions in order to obtain better spatial sampling and illumination of the target. These data when combined will provide a dataset with much-improved signal-to-noise ratio and resolution of the reservoir. A similar technique was previously used by PGS over its Varg field offshore Norway. Gravity data was also acquired simultaneously on the same dual grid, which will further aid in determining the extent of the salt bodies during processing.
In addition to the seismic objectives, the survey presented significant operational challenges including varying shallow water depths, wrecks, platforms, a gas pipeline and busy shipping lanes. It is therefore a testament to Wintershall's planning and PGS' operational efficiency that the survey was completed ahead of schedule and with minimal operational and technical downtime.
Fiona Dewey, Geophysical Advisor of Wintershall comments, " The challenges that we needed to overcome required an alternative approach that would produce results that could not have been achieved through conventional seismic acquisition techniques."