Improved seismic inversion and reservoir description of the Ichthys gas-condensate field, Browse Basin, Western Australia*
Masamichi Fujimoto A , Takeshi Yoshida B and Andrew Long CA INPEX Browse Ltd Level 31, Akasaka Biz Tower, 5-3-1, Akasaka, Minato-ku, Tokyo, Japan. Email: Masamichi.fujimoto@inpex.co.jp
B INPEX Browse Ltd Level 22, 100 St Georges Terrace, Perth, Western Australia 6000. Email: Takeshi.yoshida@inpex.com.au
C Petroleum GeoServices Level 4, IBM Centre, 1060 Hay Street, Western Australia 6005. Email: Andrew.long@pgs.com
The APPEA Journal 50(2) 716-716 https://doi.org/10.1071/AJ09080
Published: 2010
Abstract
Seismic inversion has become a standard geophysical tool to enhance seismic resolution, predict the reservoir porosity distribution, and to discriminate between reservoir and non-reservoir pay zones. Conventional seismic data does not record the low frequencies necessary for inversion. To enable a complete bandwidth, low frequencies are modelled from well data and are typically interpolated throughout the volume using seismic velocities. This often causes the resultant porosity distribution calculated from the inverted P-impedance to be biased by the well data and the geometry of well locations.
Dual-sensor GeoStreamer technology was used to acquire a regional multi-client 2D survey by PGS in 2008, including some lines over the Ichthys gas-condensate field in the Browse Basin. Dual-sensor streamer processing recovers a wider frequency bandwidth than conventional seismic. Receiver ghost removal combined with deep streamer towing simultaneously boosts both the low and high frequencies. The improved bandwidth enables a higher quality of velocity analysis, which further improves resolution throughout the section.
Simultaneous inversion of the data validated the uplift of the low frequency data, and significantly reduced the bias towards well data for the low frequency model. The resultant P-impedance data demonstrated an excellent tie to well data. The dual-sensor technology promises to improve the description of the porosity distribution within our reservoir model.
Keywords: seismic inversion, reservoir characterisation, Ichthys Field, Browse Basin, GeoStreamer, dual sensor streamer, low frequency
Masamichi Fujimoto graduated with an MSc (1997) in resource engineering from Kyoto University. He has 12 years’ industry experience, having entered the industry in 1997 with JNOC as a geophysicist. He spent four years working for the Government’s geophysics surveys, and three years working on research into fault-sealing in the technical research centre. He joined INPEX in 2004, and had been working as senior geophysicist on the Ichthys development project in the Browse Basin, Western Australia, until the end of 2009. He is now a senior geophysicist with INPEX in Tokyo, Japan. Member: SEG, EAGE and JAPT. |
Takeshi Yoshida holds an MSc (1996) in resource engineering from Tohoku University. He has worked for INPEX as a geophysicist since he joined the company in 1996. He spent four years in Jakarta as an exploration geophysicist and worked on marine seismic acquisition, data processing and seismic interpretation for the Abadi gas field in the Timor Sea, Indonesia. He has been Manager Geophysics for INPEX Perth since 2006, working on the Ichthys development project and exploration projects in the Browse Basin. Member: SEG, EAGE and JAPT. |
Andrew Long has a PhD (1996) in geophysics from UWA, and more than 20 years of experience in both the seismic industry and academia. He joined PGS in 1997, where he has served various regional and global technical roles, before taking his present role as geophysical advisor in 2007. Member: SEG, EAGE, ASEG, PESA, SPE and SEAPEX. |
References
Fujimoto, M., Takanashi, M., Chagalov, D., Szczepaniak, Y., and Yoshida, T., 2007—Application of pre-stack depth migration across the Ichthys field, Browse Basin. 19th ASEG Conference and Exhibition, Sydney, 18–22 November, expanded abstracts.(2009). GeoStreamer quantification in Australia. TechLink Newsletter 9, .
Takanashi, M., Chagalov, D., Plasterie, P., and Fujimoto, M., 2007—Investigation of overburden heterogeneity effects and their removal through high-resolution tomography and pre-stack depth migration. 19th ASEG Conference and Exhibition, Sydney, 18–22 November, expanded abstracts.
Tenghamn, R., Vaage, S., and Borresen, C., 2007—A dual-sensor, towed marine streamer—its viable implementation and initial results. 77th SEG Annual Meeting, San Antonio, expanded abstracts.
