IOCAS-IR  > 海洋地质与环境重点实验室
Downhole log evidence for the coexistence of structure II gas hydrate and free gas below the bottom simulating reflector in the South China Sea
Qian, Jin1,2,3,4; Wang, Xiujuan1,2,3,4; Collett, Timothy S.5; Guo, Yiqun6; Kang, Dongju6; Jin, Jiapeng1,2,7
2018-12-01
Source PublicationMARINE AND PETROLEUM GEOLOGY
ISSN0264-8172
Volume98Pages:662-674
Corresponding AuthorWang, Xiujuan(wangxiujuan@qdio.ac.cn)
AbstractStratigraphic layered pore-filling gas hydrates are identified above the bottom simulating reflector (BSR) using the well log and core data acquired at Sites W11 and W17 during the third gas hydrate drilling expedition conducted by China's Geological Survey/Guangzhou Marine Geological Survey (GMGS3) in the South China Sea. A seismic profile near Site W17, reveal the presence of two BSRs (i.e., double BSR), which we show to relate to zones of structure I gas hydrate (I-BSR) and structure II gas hydrate (II-BSR). Well log data from Site W17 between the "I-BSR" (projected depth of 250 mbsf) and "II-BSR" (projected depth of 330 mbsf) showed anomalous responses for gas hydrate-bearing sediments with high resistivity, high S-wave velocity, and alternating high and low P-wave velocities. Pressure core data support the interpretation that structure II gas hydrate occurs at a depth of 263 mbsf at Site W17. The cross-plot between log-derived neutron and density porosities reveals a free gas-bearing layer at a depth of 258-270 mbsf, suggesting gas hydrate coexists with free gas between the "I-BSR" and the "II-BSR." Synthetic seismograms generated from the P-wave velocity and density logs further support the presence of free gas in this section. Based on the coexistence of hydrate, free gas and water, the simplified three-phase equation (STPE) was modified to simultaneously estimate free gas and hydrate saturations beneath the "I-BSR" from P-wave and S-wave velocity logs, assuming uniform or patchy distributions of free gas. The estimated free gas and hydrate saturations, together with gas compositions from pressure core samples, collectively indicate that structure II gas hydrate and free gas are interbedded and coexist below the "I-BSR" at Site W17. Our study of the coexistence of gas hydrate and free gas between the double BSR at Site W17 provides new insights into gas hydrate systems in nature that contain more complex gas chemistries.
KeywordStructure II gas hydrate Free gas Saturation Interbedded Coexistence
DOI10.1016/j.marpetgeo.2018.09.024
Indexed BySCI
Language英语
Funding ProjectNational Key R&D Program of China[2017YFC0307601] ; National Natural Science Foundation of China[41676040] ; National Natural Science Foundation of China[41676041]
WOS Research AreaGeology
WOS SubjectGeosciences, Multidisciplinary
WOS IDWOS:000451360000044
PublisherELSEVIER SCI LTD
Citation statistics
Document Type期刊论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/156097
Collection海洋地质与环境重点实验室
Corresponding AuthorWang, Xiujuan
Affiliation1.Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Peoples R China
2.Chinese Acad Sci, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China
3.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Mineral Resources, Qingdao 266071, Peoples R China
4.Chinese Acad Sci, Ctr Ocean Megasci, Qingdao 266071, Peoples R China
5.US Geol Survey, Denver Fed Ctr, Box 25046,MS939, Lakewood, CO 80225 USA
6.MLR, Guangzhou Marine Geol Survey, Guangzhou 510760, Guangdong, Peoples R China
7.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
First Author AffilicationInstitute of Oceanology, Chinese Academy of Sciences
Corresponding Author AffilicationInstitute of Oceanology, Chinese Academy of Sciences
Recommended Citation
GB/T 7714
Qian, Jin,Wang, Xiujuan,Collett, Timothy S.,et al. Downhole log evidence for the coexistence of structure II gas hydrate and free gas below the bottom simulating reflector in the South China Sea[J]. MARINE AND PETROLEUM GEOLOGY,2018,98:662-674.
APA Qian, Jin,Wang, Xiujuan,Collett, Timothy S.,Guo, Yiqun,Kang, Dongju,&Jin, Jiapeng.(2018).Downhole log evidence for the coexistence of structure II gas hydrate and free gas below the bottom simulating reflector in the South China Sea.MARINE AND PETROLEUM GEOLOGY,98,662-674.
MLA Qian, Jin,et al."Downhole log evidence for the coexistence of structure II gas hydrate and free gas below the bottom simulating reflector in the South China Sea".MARINE AND PETROLEUM GEOLOGY 98(2018):662-674.
Files in This Item:
There are no files associated with this item.
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[Qian, Jin]'s Articles
[Wang, Xiujuan]'s Articles
[Collett, Timothy S.]'s Articles
Baidu academic
Similar articles in Baidu academic
[Qian, Jin]'s Articles
[Wang, Xiujuan]'s Articles
[Collett, Timothy S.]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[Qian, Jin]'s Articles
[Wang, Xiujuan]'s Articles
[Collett, Timothy S.]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.