Optimizing source repeatability in wide azimuth surveys

Wide-AZimuth (WAZ) marine streamer survey designs are aimed at increasing the crossline offset and azimuth distributions in marine streamer surveys to better image complex geologies and the sub-salt. Since there is a limited amount of crossline offset that can be achieved with a conventional narrow-azimuth towed streamer spread, most WAZ survey designs have aimed at decoupling sources and receivers, placing the sources laterally from the receiver spread to achieve the additional offset. Successive passes down the same source lines are then required to extend the offsets. This leads to the familiar concept of a 4D acquisition, where the primary (and most realistic) goal is to achieve a repeat position of the Center Of Source (COS). As WAZ-type acquisitions can require multiple sail-line passes to achieve the required crossline offset, and most require a shot regularization to a fixed grid, it becomes increasingly important to minimize errors in source positioning.