ABSTRACT

The Bonaparte Basin is well-positioned to support Australia’s Future Gas Strategy, with proven gas-prone petroleum systems ideal for future carbon capture and storage (CCS) and liquefied natural gas (LNG) development. From a drilling perspective, the shallow water depths (70–230 m) present accessible resource opportunities but pose significant challenges for seismic survey operations and subsurface imaging. In early 2024, following a detailed survey design study, a seismic acquisition was carried out using a single vessel towing 12 streamers of 8000-m length with 112.5-m streamer separation, and three acoustic sources at 50-m shotpoint intervals. This survey aimed to improve subsurface imaging of the eastern Vulcan Sub-basin and Londonderry High. Despite challenges – restricted manoeuvrability, carbonate pinnacles, strict environmental controls, plus local and foreign fishers – seismic data were acquired using continuous-line acquisition (CLA) in a racetrack pattern. This approach significantly reduced the survey duration, completing 6808 km² in just 76 days. Acquiring seismic data with a wide streamer tow and CLA in shallow water demands additional signal processing considerations. The sparse near-offset coverage poses challenges for demultiple, velocity model building, and imaging. To address this, innovative seismic imaging technologies and workflows were deployed. The resulting new seismic image provides improved understanding of the subsurface previously restricted by the quality of legacy seismic which was unable to resolve shallow carbonate intervals and complex faulting. Along with the results, we will also discuss how these technologies could shorten future seismic survey duration and enhance reprocessing of legacy seismic data.