Volume 33, Issue 3
  • ISSN: 0263-5046
  • E-ISSN: 1365-2397


Undershooting, a technique for acquisition of seismic data beneath areas that are difficult to access at the surface of the Earth, has long been practised in the field of 3D seismic exploration. The publication of new guidelines by the OGP for the Conduct of Offshore Drilling Hazard Site Surveys specifies that seismic data greater than ten years old are no longer valid for this application. Hence, there is a need to be able to use the undershoot technique in the evaluation of shallow sub-sea hazards beneath existing structures such as Production Platforms if new wells are planned to be drilled from these structures. This paper outlines the approach taken using two multi-role site survey vessels to acquire a high-resolution undershoot dataset, with the emphasis being to ensure that this was suitable for shallow geohazard evaluation. We describe the techniques and equipment, including specifically designed in-house navigation software routines, the trials undertaken, and the successful acquisition of a useable dataset. Examples are provided that demonstrate the high quality of the seismic dataset acquired. It was only possible to achieve this using a 3D approach for the binning and processing of the seismic data.


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  • Article Type: Research Article
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