A Synthetic Simultaneous Source Wide-azimuth Acquisitions Study over a Complex Marine Environment

Marine blended source acquisition is becoming increasingly important in the seismic industry due to the possibility of reducing costs through higher productivity and improving seismic data quality through denser source sampling. One major drawback of marine blended acquisition is the crosstalk noise generated by the nearly simultaneous firing of the source arrays. It is essential to understand the characteristics of this type of noise interference and identify proper acquisition techniques and processing workflows to reduce its effects on image quality. We start by 3D finite difference modelling of a complex subsurface. We then combine the synthetic shots to simulate a four boat, wide azimuth (WAZ) marine seismic survey comprised of two streamer vessels with sources, and two additional source vessels located between the streamer spreads and off the tails of the streamers. All four sources fire nearly simultaneously with a randomized time lag of up to 500 milliseconds between sources. Overall, the gain from near-simultaneous source firing versus a conventional four-vessel WAZ marine design is an increase of approximately 2.67 times in terms of both source density and fold. This type of blended acquisition survey can also be acquired in about the same amount of acquisition time as a conventional four vessel WAZ survey. In general, most of the processing techniques for the simultaneous source blended data rely on the fact that crosstalk noise exhibits coherency in the shot domain, but appears random when viewed in a different data domain such as common channel, offset and midpoint domains. A number of processing techniques are applied in order to optimally deblend the data. These techniques are tested in several different domains and also in a cascaded manner. The results and effectiveness of each technique is evaluated and compared against the original non-blended synthetic data. Direct comparisons between the processed blended data and the single source non-blended data reveal comparable seismic images in both the prestack and post-stack domains.