Pore morphology, permeability, and constraints on gas hydrate accumulation in sediments from the Tuaheni Landslide Complex, NZ

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http://abstractsearch.agu.org/meetings/2018/FM/OS51F-1331.html
Author(s): Nole, Michael; Daigle, Hugh; Dugan, Brandon; Clennell, Michael B.; Paganoni, Matteo; Barnes, Philip; Pecher, Ingo Andreas; LeVay, Leah
International Ocean Discovery, Program Expedition 372 Scientists, College Station, TX
Author Affiliation(s): Primary:
Sandia National Laboratories, Albuquerque, NM, United States
Other:
University of Texas at Austin, United States
Colorado School of Mines, United States
CSIRO Earth Science Resource Engineering, Australia
Shell Global Solutions International, Netherlands
National Institute of Water and Atmospheric Research, New Zealand
University of Auckland, New Zealand
Texas A&M University, United States
Volume Title: AGU 2018 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2018; American Geophysical Union 2018 fall meeting, Washington, DC, Dec. 10-14, 2018. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: As part of International Ocean Discovery Program Expedition 372, well logging and core sampling was performed in the Tuaheni Landslide Complex (TLC) offshore New Zealand to better understand the relationships between fluid flux, gas hydrate formation and distribution, and the behavior of submarine landslides. We present a preliminary analysis tying physical properties of core samples with well log data acquired at TLC Site U1517 to understand lithologic controls on gas hydrate growth in these sediments. We performed a series of measurements on sediments within and immediately below the landslide complex, including constant rate of strain consolidation tests to determine permeability, and nuclear magnetic resonance (NMR) T2distribution and mercury injection capillary pressure (MICP) analysis of pore size distributions. We use laboratory NMR conditioned by MICP measurements to calibrate well log NMR data and estimate pore size distribution as a function of depth in these sediments. We additionally compare grain shape and size across significant changes in lithology using QEMSCAN electron microscopy. Our results indicate that the predominance of pores smaller than 1 micron in fine-grained sediments throughout most of the sediment column likely inhibits hydrate growth and promotes the preferential accumulation of hydrate in very thin, coarser-grained turbidites (grains larger than 50 microns) from 105 to 170 mbsf (beneath the depth of the landslide mass). Furthermore, low vertical permeability and minimal overpressure currently observed at this site make hydrate formation due to advective methane migration difficult, though this does not rule out a hydrate charging mechanism related to episodic overpressuring.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 07 Marine Geology and Oceanography; Australasia; Expedition 372; Gas hydrates; Hikurangi Margin; IODP Site U1517; International Ocean Discovery Program; Marine sediments; Mass movements; New Zealand; Pacific Ocean; Permeability; Sediments; Slumping; South Pacific; Southwest Pacific; Tuaheni Complex; West Pacific
Coordinates: S384947 S384947 E1782834 E1782834
Record ID: 2019061711
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