Dual Coil Shooting

Ultra-long offset and full azimuth data achieved with enhanced Coil Shooting technique

WesternGeco Coil Shooting acquisition delivers full-azimuth (FAZ) data using a single vessel, and not only delivers better azimuthal coverage, but can be highly cost-effective compared to other techniques. To acquire a Coil Shooting survey, the vessel sails in a series of overlapping, continuously linked circles.

In the second half of 2010, WesternGeco further developed the method by performing Coil Shooting with multiple vessels to address extreme imaging challenges requiring very long offset data. Dual Coil Shooting involves two recording vessels with their own sources and two separate source vessels, all sailing in large (12–15 km) diameter interlinked circles. The trace density of this design is approximately 2.5 times that of current WAZ survey designs, and the resulting very high fold will improve signal-to-noise ratio to further improve the imaging of weak subsalt reflections.

The Dual Coil Shooting technique is supported by the WesternGeco DSC dynamic spread control system, which automatically controls the vessel, streamer, and source positions, maintains the positioning of the sources based on the preplot, and keeps constant streamer separation.

The departure from traditional linear shooting patterns presents processing challenges due to factors such as different noise modes, the offset and azimuth characteristics, and higher volumes of data. WesternGeco has developed processing methods—many based on the unique point-receiver recordings available from the Q-Marine point-receiver marine seismic system—to address these challenges.

WesternGeco believes that this new design of marine seismic acquisition will address some of the many remaining imaging challenges in mature and frontier areas, and expects to see many further Coil Shooting and Dual Coil Shooting projects around the world over the coming months and years.

Related services and products