Time-lapse crosswell seismic tomography for monitoring the CO 2 injected into an onshore aquifer, Nagaoka, Japan

PreviousNext No AccessProceedings of the 8th SEGJ International Symposium, Kyoto, Japan, 26-28 November 2006Time-lapse crosswell seismic tomography for monitoring the CO2 injected into an onshore aquifer, Nagaoka, JapanAuthors: Hideki SaitoDai NobuokaHiroyuki AzumaDaiji TanaseZiqiu XueHideki Saito Oyo Corporation ()Search for more papers by this authorEmail the author at [email protected], Dai Nobuoka Oyo Corporation ()Search for more papers by this authorEmail the author at [email protected], Hiroyuki Azuma Oyo Corporation ()Search for more papers by this authorEmail the author at [email protected], Daiji Tanase Engineering Advancement Association of Japan (ENAA)Search for more papers by this author, and Ziqiu Xue Research Institute of Innovative Technology for the Earth (RITE)Search for more papers by this authorhttps://doi.org/10.1190/segj082006-001.66 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Japan's first pilot-scale CO2 geological sequestration experiment has been conducted at the Minami-Nagaoka gas and oil field. One injection well (IW-1) and three observation wells (OB-2, OB-3, and OB-4) were drilled at the pilot site. CO2 was injected from IW-1 at 20–40 t per day. The depth of the reservoir consisting of a 60 m-thick sandstone bed of the Haizume Formation is about 1100 m below the ground surface. A thin permeable layer having a thickness of 12 m within the reservoir was selected for injection of CO2. The total amount of injected CO2 was 10400 t. Among various measurements conducted at the site for monitoring the injected CO2, we conducted time-lapse crosswell seismic tomography between two observation wells OB-2 and OB-3 to determine the distribution of CO2 in the aquifer by the change of seismic P-wave velocities. The crosswell seismic tomography measurements were carried out five times; once before the injection as a baseline survey, and four times during and after the injection as monitoring surveys. The velocity tomograms obtained from the monitoring surveys were compared to the baseline survey tomogram, and velocity difference tomograms were generated. The velocity difference tomograms showed that velocity had decreased in a part of the aquifer around the injection well, where the injected CO2 was supposed to be distributed. We also found that the area in which velocity had decreased was expanding in the formation up-dip direction, as increasing amounts of CO2 injected until 8900 t of CO2 had been injected. However, we have not observed any velocity changes after 8900 t of CO2 injected. The maximum velocity reductions observed in the velocity difference tomograms were 3.5% after 8900 t of CO2 had been injected. Permalink: https://doi.org/10.1190/segj082006-001.66FiguresReferencesRelatedDetails Proceedings of the 8th SEGJ International Symposium, Kyoto, Japan, 26-28 November 2006ISBN (print):978-4-938493-09-7ISSN (online):2159-6832Copyright: 2006 Pages: publication data© 2006 Published in electronic format with permission by the Society of Exploration Geophysicists of JapanPublisher:Society of Exploration Geophysicists HistoryPublished Online: 08 Nov 2012 CITATION INFORMATION Hideki Saito, Dai Nobuoka, Hiroyuki Azuma, Daiji Tanase, and Ziqiu Xue, (2006), "Time-lapse crosswell seismic tomography for monitoring the CO2 injected into an onshore aquifer, Nagaoka, Japan," SEG Global Meeting Abstracts : 1-4. https://doi.org/10.1190/segj082006-001.66 Plain-Language Summary PDF DownloadLoading ...