Dan Field Ocean Bottom Node (OBN) Survey - A Shallow Water Case History

In 2012 Maersk Oil acquired an Ocean Bottom Node (OBN) seismic survey over the Dan Field located in shallow water in the Danish North Sea. The survey took place shortly after a regional multi-field 4D monitor streamer survey which included the area around the Dan Field. The primary objective of the OBN survey was to acquire data in an area affected by surface infrastructure not accessible with streamer technology. Secondary objectives included evaluating the imaging results in comparison with streamer technology on a field wide scale and evaluating the matching quality between the vintage streamer and OBN survey data. Significant challenges due to the shallow water environment were overcome during operations as well as processing. The results show a clear improvement with the OBN data in the area affected by the platforms when compared to the streamer data in-filled with conventional two boat undershooting. The OBN image is of a similar or better quality over most of the field when compared to the streamer result allowing for different strategic options for future seismic surveys in this area.