Blended Acquisition and Deblending Processing of 3D Ocean Bottom Node Data

Abstract

Summary The time required to acquire an ocean bottom node seismic survey is usually dominated by the shooting time, rather than the node deployment and retrieval time. By overlapping sources in time, blended ocean bottom node acquisition enables the recording of high quality data that is well sampled in azimuth, offset and space at a cost significantly less than that of an equivalent unblended survey. We acquire blended data with two source vessels in the Main Pass area of the Gulf of Mexico. A key feature of the acquisition geometry is the pseudo-randomization of the source positions, which creates large effective time dither between the two sources. We successfully deblend these data using a method based on the iterative coherency constrained technique developed at Delft University. Although the Main Pass data are acquired with large spatial separation between the source vessels, numerical blending of single source data acquired with the same geometry shows that the deblending effectiveness is very insensitive to the source separation; a finding that may be important in planning surveys where both sources are constrained to operate in close proximity.