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Submarine Channels Characterization using Seismic Attribute Analysis: A Case Study from Browse Basin, Offshore Australia
  • Fawz Naim
Fawz Naim
Schlumberger

Corresponding Author:[email protected]

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Abstract

CHALLENGES Submarine channels, erosional features on the world’s continental margins, are of great interest as they prove to be a prolific reservoir around Gulf of Mexico, offshore Brazil and western coast of Africa. The main challenge is to highlight the channels and extract them as 3D objects from 3D-seismic data, as conventional approach to delineate and map submarine channels in current data set is difficult owing to presence of subtle thin submarine channels. METHODOLOGY This 3D-seismic survey from Poseidon 3D prospect of the Browse Basin spans an area of 4070 km with an orientation of 310° North. Submarine channels are present in the Late Cretaceous Woolaston formation. Generalized Spectral Decomposition and Sweetness attributes have been used in this study to identify submarine channels. Generalized Spectral Decomposition attribute volumes were generated at different frequencies to identify some of the resolved channels. The Sweetness attribute, on the other hand, was helpful in distinguishing other channels based on the amplitude envelope and instantaneous frequency. The Sweetness attribute, after blending with Generalized Spectral Decomposition attribute, was used for Geobody (3-D objects) extraction from the seismic data. Significant enhancement of channels and suppressing background features was accomplished by controlling the opacity of the volume. It was followed by extraction and editing of Geobodies. RESULT AND CONCLUSION The current data set in Browse basin has up to 10 submarine channels in Cretaceous, most of them being subtle and difficult to map in 3D-seismic data. An alternate methodology to characterize submarine channels by using Generalized Spectral Decomposition and Sweetness attribute helped to mitigate the challenge. Generalized Spectral Decomposition attribute could delineate some submarine channels that got tuned at specific frequencies. The Sweetness attribute was helpful in distinguishing other channels using the amplitude envelope and instantaneous frequency. Further, the process of extracting submarine channels as ‘Geobodies’ from seismic volume, proved to be very valuable as it can be directly used for volumetric estimation of prospects. Thus, the methodology discussed in this study can be used as a reference to characterize and quantify submarine channels.