Summary

We use a finite-difference model to help design an ocean-bottom acquisition for offshore Trinidad, where imaging is obscured by large shallow gas accumulations in the overburden. Gas is represented in our model by low velocities and attenuation values (Q) between 3 and 27; reflectivity is created using a density model. We simulate two acquisition methods over an 18x10 km area: one to represent ocean-bottom cable-style acquisition and one to simulate autonomous node acquisition. Results indicate that the wide azimuth coverage acquired during both the node and cable cases greatly improve the image through the shallow gas compared to the most recent narrow azimuth towed streamer data in Trinidad. The model also demonstrates the importance of an accurate migration velocity model in recovering events below the gas.

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