Successful Delineation of Sand Bodies in an Area of Limited Seismic Reflectivity - A Study from the Western Timor Sea

Overlapping compaction trends for sand and shale lithologies combined with complex overburden geology has led to poor seismic imaging capabilities at the Mesozoic level in the Vulcan Sub-Basin, Western Timor Sea, Australia. To achieve a significant improvement in seismic data quality the broadband Sandalford 3D seismic dataset was acquired in 2012. A rock physics study conducted in 2013, using key well data from the area, showed that sand and shale trends were both partially overlapping for both AI and Vp/Vs. However, it was concluded that the two lithologies could be separated through a multi-stack inversion followed by a Bayesian lithology classification. Following the seismic processing and initial seismic interpretation the broadband seismic dataset was subject to a deterministic multi-stack inversion in 2013. This case study demonstrates how new technologies and detailed quantitative interpretation studies can significantly improve the seismic data quality and the definition of the reservoir facies distribution in an area with a history of particular seismic imaging difficulties.