The Successful Design, Development and Acquisition of a UHRS 3D Seismic Dataset

Exploration 3D has become commercially beneficial because vessels can tow multiple streamers, often with multiple sources. The data can also be acquired in relatively rough seas, with large areas covered in a short time. There are two main downsides to this 3D data acquisition. Firstly, the frequency content of the data is low - typically ~ 60Hz. This limits the vertical resolution of the data. Secondly, because of the large offsets between the source and streamers, any ‘shallow’ data will be very poorly imaged. This lack of high frequency content cannot be completely solved due to the nature of seismic waves. The frequency can be enhanced by processing techniques but these have limitations and can only achieve a limited improvement in resolution. So if higher resolution is required, then the only solution is to use HR or UHR techniques. This may be needed for shallow reservoir delineation, geohazards including shallow gas, carbon capture in salt caverns, and foundation studies. However, while the benefits of HRS or UHRS data are well known and accepted, there has been a reluctance to move from 2D to 3D acquisition. This paper describes the successful planning, development and application of just such a 3D spread.