RR459 - Use of 3D Seismic data as a substitute for high-resolution seismic surveys for site investigation

The assessment of geohazards is usually conducted using high-resolution seismic surveys. However, in many deep-water exploration areas worldwide 3D seismic data are now routinely employed for site investigation work as well as basic prospect exploration as this helps to reduce costs. Nevertheless, not all 3D surveys necessarily lend themselves to this task due to their acquisition design and processing. Geohazards are briefly discussed and critical acquisition and processing parameters are presented that influence the suitability of 3D surveys for site investigation work. Published guidelines and industry practice suggest that where 3D surveys have specifically targeted the seabed and near-seabed section a vertical resolution of 6 m and finer is possible in water depths greater than 500 m. This is comparable to a conventional site survey vertical resolution of 4 - 5 m. However, many 3D surveys where the seabed was not a target possess significantly lower vertical resolutions of ~10 m and are not fit as a substitute for site surveys.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

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Updated 2021-04-20