Combining WATS and OBN Data for OBN Free-surface Multiple Removal - A Case Study in Deep-water Gulf of Mexico

Abstract

Ocean Bottom Node (OBN) acquisition is increasing in popularity due to its inherent benefits such as full azimuth coverage, long offsets, rich low frequencies, and high signal-to-noise ratio. In order to obtain a good reservoir image, the multiple wavefield must be properly removed from OBN data. However, due to the high acquisition cost, OBN surveys usually have sparse receiver sampling. Additionally, the difference between their source and receiver datums is significant. These two factors make conventional SRME inapplicable to OBN surveys alone. By incorporating an existing wide azimuth towed streamer (WATS) survey, we are able to overcome the OBN obstacles for traditional SRME application. In this paper, we present a practical 3D OBN SRME flow, which combines OBN and WATS data for OBN free-surface multiple prediction. Our flow does not require any velocity and reflectivity information, and naturally predicts the whole set of free-surface related multiples with the data’s full bandwidth preserved. Its effectiveness in removing OBN multiples from complex subsalt settings has been proven in many practical applications. We show the application of our flow on an OBN survey from the deep-water, Gulf of Mexico. The multiples have been effectively removed, and subsalt images become clearer and more coherent.