Collett, Timothy S. and 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

Leg/Site/Hole:
ODP 164
ODP 164 994
ODP 164 995
ODP 164 997
Identifier:
2001-025814
georefid
10.2973/odp.proc.sr.164.219.2000
doi
Creator:
Collett, Timothy S.
U. S. Geological Survey, Denver Federal Center, Denver, CO, United States
author
Ladd, John
University of Tokyo, Japan
author
Identification:
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
2000
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
Texas A & M University, Ocean Drilling Program, College Station, TX, United States
164
179-191
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.
English
Serial
Coverage:Geographic coordinates:
North:31.5035
West:-75.3245East: -75.2807
South:31.4708
Economic geology, geology of energy sources; Applied geophysics; Atlantic Ocean; Blake-Bahama Outer Ridge; bottom-simulating reflectors; concentration; continental margin; Formation MicroScanner; gas hydrates; geochemical methods; geophysical methods; geophysical profiles; geophysical surveys; Leg 164; marine sediments; natural gas; North Atlantic; Ocean Drilling Program; ODP Site 994; ODP Site 995; ODP Site 997; petroleum; physical properties; porosity; potential deposits; reservoir rocks; resistivity; saturation; sediments; seismic methods; seismic profiles; surveys; volume; well-logging;
.