Collett, Timothy S.; Ladd, John (2000): Detection of gas hydrate with downhole logs and assessment of gas hydrate concentrations (saturations) and gas volumes on the Blake Ridge with electrical resistivity log data. Texas A & M University, Ocean Drilling Program, College Station, TX, United States, In: Paull, Charles K., Matsumoto, Ryo, Wallace, Paul J., Black, Nancy R., Borowski, Walter S., Collett, Timothy S., Damuth, John E., Dickens, Gerald R., Egeberg, Per Kristian, Goodman, Kim, Hesse, Reinhard F., Hiroki, Yoshihisa, Holbrook, W. Steven, Hoskins, Hartley, Ladd, John, Lodolo, Emanuele, Lorenson, Thomas D., Musgrave, Robert J., Naehr, Thomas H., Okada, Hisatake, Pierre, Catherine, Ruppel, Carolyn D., Satoh, Mikio, Thiery, Regis, Watanabe, Yoshio, Wehner, Hermann, Winters, William J., Wood, Warren T., Miller, Christine M. (editor), Reigel, Ruth (editor), Proceedings of the Ocean Drilling Program; volume 164; scientific results; gas hydrate sampling on the Blake Ridge and Carolina Rise; covering Leg 164 of the cruises of the drilling vessel JOIDES Resolution, Halifax, Nova Scotia, to Miami, Florida, sites 991-997, 31 October-19 December 1995, 164, 179-191, georefid:2001-025814

Abstract:
Leg 164 of the Ocean Drilling Program was designed to investigate the occurrence of gas hydrate in the sedimentary section beneath the Blake Ridge on the southeastern continental margin of North America. Sites 994, 995, and 997 were drilled on the Blake Ridge to refine our understanding of the in situ characteristics of natural gas hydrate. Because gas hydrate is unstable at surface pressure and temperature conditions, a major emphasis was placed on the downhole logging program to determine the in situ physical properties of the gas hydrate-bearing sediments. Downhole logging tool strings deployed on Leg 164 included the Schlumberger quad-combination tool (NGT, LSS/SDT, DIT, CNT-G, HLDT), the Formation MicroScanner (FMS), and the Geochemical Combination Tool (GST). Electrical resistivity (DIT) and acoustic transit-time (LSS/SDT) downhole logs from Sites 994, 995, and 997 indicate the presence of gas hydrate in the depth interval between 185 and 450 mbsf on the Blake Ridge. Electrical resistivity log calculations suggest that the gas hydrate-bearing sedimentary section on the Blake Ridge may contain between 2 and 11 percent bulk volume (vol%) gas hydrate. We have determined that the log-inferred gas hydrates and underlying free-gas accumulations on the Blake Ridge may contain as much as 57 trillion m (super 3) of gas.
Coverage:
West: -75.3245 East: -75.2807 North: 31.5035 South: 31.4708
Relations:
Expedition: 164
Site: 164-994
Site: 164-995
Site: 164-997
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.164.219.2000 (c.f. for more detailed metadata)
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