Complete wavefield seismic structural, stratigraphic, geomorphic and elastic interpretation in the offshore Browse Basin
Andrew Long A , Dushyan Rajeswaran A , Jennifer Greenhalgh A , Cyrille Reiser A and Nizar Chemingui APGS.
The APPEA Journal 56(2) 557-557 https://doi.org/10.1071/AJ15063
Published: 2016
Abstract
The first quantitative interpretation project in the Browse Basin that used complete wavefields from dual-sensor streamer data to characterise a variety of overburden and reservoir seismic structural, sedimentary and geomorphic features is discussed in this extended abstract.
Having established that complete wavefield pre-stack angle data are amplitude versus angle (AVA) compliant, the authors analyse the elastic response from thin gas sands in a location where well control predicts a weak gas response in terms of the Vp/Vs ratio and negligible response in terms of the acoustic impedance.
Various seismic expressions in the near-surface are better resolved using complete wavefield imaging, including deltaic deposits, potentially prospective patch reefs and intersecting channel systems, and shallow hazards associated with historic drilling failures appear to be resolvable with greater confidence.
On the larger scale, the overall data interpretability is substantially enhanced in texture and character by broadband imaging of primary reflections, and then by subsequent reservoir characterisation.
Initial (deeper) interpretation focused around mapping of the prospective Early Jurassic Plover Formation and the Early Cretaceous Upper Vulcan Formation, in which evidence of channelisation can be demonstrated on conventional migration volumes and reinforced using complete wavefield migration. Ultra-low frequency signal penetration to the deeper Triassic level has been limited historically, but the first complete seismic wavefield data analysis presented demonstrates that a combination of volume attributes provide substantially improved geologic information from the seafloor to the deepest targets.
Andrew Long has a PhD in geology from the University of Western Australia (UWA), and is chief scientist for geoscience and engineering in PGS, having been with PGS since 1997. Prior to PGS he worked for various service companies and did post-doctoral research at Stanford University. Member: PESA, SEG, EAGE, ASEG and South East Asia Petroleum Exploration (SEAPEX). |
Dushyan Rajeswaran has a BSc (Hons) in geophysics from Curtin University, is senior geoscientist for reservoir services in PGS, having been been with PGS since 2014. Prior to PGS he was with ExxonMobil for six years. Member: PESA, ASEG, SEAPEX. |
Jenny Greenhalgh has a PhD in geology from University College London, and is principal geologist and Asia-Pacific team leader for the reservoir interpretation team at PGS, and has been with PGS since 2005. Prior to PGS she was with TGS. Member: PESA, SEAPEX. |
Cyrille Reiser has a PhD in geology from Lyon’s Ecole Normale, and is reservoir characterisation director for reservoir services in PGS, and has been with PGS since 2008. Prior to PGS he was with CGG, specialising in reservoir characterisation. Member: SEG, EAGE, PESGB |
Nizar Chemingui has a PhD in geophysics from Stanford University, and is department manager in depth imaging research and development for geoscience and engineering in PGS. He has been with PGS since 2006. Prior to PGS he was with ExxonMobil as a research geophysicist in the subsurface imaging division and with GXT (now ION) as a senior research geophysicist. Member: SEG, EAGE, AGU), and the Geophysical Society of Houston (GSH). |
References
Digance, C.J., 2012—A seismic sequence stratigraphic model of Miocene reef systems, their depositional environment and implications for shallow drilling hazards in the Browse Basin, North West Shelf, Australia. Geoscience Honours thesis, University of Adelaide.Greenhalgh, J., and Irving, R. (2016). Geologic Geophysical Challenges that were overcome with the use of technology Caswell subbasin, Browse Basin. The Leading Edge 35, 27–31.
Whitmore, N.D., Valenciano, A.A., Sollner, W. And Lu, S., 2010—Imaging of primaries and multiples using a dual-sensor towed streamer. SEG Annual Meeting, Denver, Colorado, USA, October 17–22, SPMI 2.8.
