Industry Article: Full-azimuth imaging using circular geometry acquisition

 

Wide-azimuth (WAZ) towed streamer acquisition has improved the quality and reliability of subsalt imaging in the Gulf of Mexico, where WAZ surveys have typically been acquired using 3–4 seismic vessels, each shooting in straight parallel lines. However, acquisition of WAZ data using a single vessel and a circular geometry off ers several potential advantages,both for operational efficiency and geophysical analysis of subsurface rock properties. Modeling exercises indicate that circular acquisition geometry can deliver a better range of azimuths and off sets than parallel WAZ geometry. A feasibility test in the Gulf of Mexico shows that it is possible to sail along circles while maintaining constant streamer separation and achieving very accurate receiver positioning.  Single-sensor recording enables eff ective attenuation of the additional coherent noise introduced by shooting in a curve. Prestack depth-migrated data from the circular geometry test compare favorably with a parallel geometry WAZ data set acquired previously.

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