Reaching the Pantheon: A Multidisciplinary Approach to Data Reprocessing and Depth Imaging in the Vulcan Sub-basin.

This study presents the results of reprocessing a 580 km2 subset of the narrow-azimuth Pantheon 3D survey, which was acquired in 2005 in the Vulcan Sub-basin, Timor Sea. The primary objective of the reprocessing was to improve data quality around the Vesta structure, where prospectivity depends on understanding the extent of potential reservoir sands associated with the adjacent Oxfordian delta system. Previous attempts at the processing of this dataset were made in 2007 and later in 2011, as part of a MAZ reprocessing effort. This project was initiated to address persistent issues with image degradation and to provide a clearer characterisation of the Oxfordian reservoir sand, and other potential exploration targets. During the reprocessing, significant improvements in image quality were realised, using only the narrow-azimuth data, through the cumulative and careful application of many modern processing methods. Of note, the impactful steps included de-multiple, de-noise, de-ghosting, velocity model building, constrained FWI and high-resolution tomography. Depth imaging using Q tomography also assisted in reducing data degradation beneath hydrocarbon-related diagenetic zones (HRDZ) and minor traps containing escaped gas from the underlying petroleum system. The reprocessing project benefitted from a multidisciplinary collaboration between diverse skillsets including signal processing, velocity model building, rock physics, potential field modelling and imaging.