Coil Shooting on Tulip discovery in Indonesia: a summary of the work done and lessons learned until now

Coil Shooting [French, Cole, 1984; Durrani, 1987] is a technique in which a marine towed streamer vessel acquires an almost continuous sequence of circular "lines". The circular line geometry is repeated in the X and Y directions to build up fold, offset and azimuth distribution. This method allows for full azimuth (FAZ) acquisition using a single vessel, shooting on a continuous turn. The time between each circular line is of the order of minutes, as opposed to hours compared to conventional race-track acquisition. This results in high acquisition uptime and efficiency. Eni Indonesia and WestenGeco shot and processed through PSDM a full 3D Circular Shooting survey (Coil) over the Tulip Discovery in Indonesia between August 2008 and February 2010. Compared to “traditional” streamer surveys, the circular geometry introduces several differences and a number of new challenges, including proper offset / azimuth stacking. This paper presents the steps of the whole project: design, onboard illumination QC and final imaging results of this new “Full Azimuth” (FAZ) seismic effort.<br>