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Title: Physical property changes in hydrate-bearingsediment due to depressurization and subsequent repressurization

Abstract

Physical property measurements of sediment cores containing natural gas hydrate are typically performed on material exposed at least briefly to non-in situ conditions during recovery. To examine effects of a brief excursion from the gas-hydrate stability field, as can occur when pressure cores are transferred to pressurized storage vessels, we measured physical properties on laboratory-formed sand packs containing methane hydrate and methane pore gas. After depressurizing samples to atmospheric pressure, we repressurized them into the methane-hydrate stability field and remeasured their physical properties. Thermal conductivity, shear strength, acoustic compressional and shear wave amplitudes and speeds are compared between the original and depressurized/repressurized samples. X-ray computed tomography (CT) images track how the gas-hydrate distribution changes in the hydrate-cemented sands due to the depressurization/repressurization process. Because depressurization-induced property changes can be substantial and are not easily predicted, particularly in water-saturated, hydrate-bearing sediment, maintaining pressure and temperature conditions throughout the core recovery and measurement process is critical for using laboratory measurements to estimate in situ properties.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Earth Sciences Division
OSTI Identifier:
934990
Report Number(s):
LBNL-664E
Journal ID: ISSN 0148-0227; JGREA2; TRN: US200815%%73
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research
Additional Journal Information:
Journal Volume: 113; Journal Issue: B07102; Related Information: Journal Publication Date: 2008; Journal ID: ISSN 0148-0227
Country of Publication:
United States
Language:
English
Subject:
54; 58; ACOUSTICS; AMPLITUDES; ATMOSPHERIC PRESSURE; COMPUTERIZED TOMOGRAPHY; DEPRESSURIZATION; DISTRIBUTION; GAS HYDRATES; HYDRATES; METHANE; NATURAL GAS; PHYSICAL PROPERTIES; SAND; SEDIMENTS; SHEAR; SHEAR PROPERTIES; STABILITY; STORAGE; THERMAL CONDUCTIVITY

Citation Formats

Kneafsey, Timothy, Waite, W F, Kneafsey, T J, Winters, W J, and Mason, D H. Physical property changes in hydrate-bearingsediment due to depressurization and subsequent repressurization. United States: N. p., 2008. Web.
Kneafsey, Timothy, Waite, W F, Kneafsey, T J, Winters, W J, & Mason, D H. Physical property changes in hydrate-bearingsediment due to depressurization and subsequent repressurization. United States.
Kneafsey, Timothy, Waite, W F, Kneafsey, T J, Winters, W J, and Mason, D H. Sun . "Physical property changes in hydrate-bearingsediment due to depressurization and subsequent repressurization". United States. https://www.osti.gov/servlets/purl/934990.
@article{osti_934990,
title = {Physical property changes in hydrate-bearingsediment due to depressurization and subsequent repressurization},
author = {Kneafsey, Timothy and Waite, W F and Kneafsey, T J and Winters, W J and Mason, D H},
abstractNote = {Physical property measurements of sediment cores containing natural gas hydrate are typically performed on material exposed at least briefly to non-in situ conditions during recovery. To examine effects of a brief excursion from the gas-hydrate stability field, as can occur when pressure cores are transferred to pressurized storage vessels, we measured physical properties on laboratory-formed sand packs containing methane hydrate and methane pore gas. After depressurizing samples to atmospheric pressure, we repressurized them into the methane-hydrate stability field and remeasured their physical properties. Thermal conductivity, shear strength, acoustic compressional and shear wave amplitudes and speeds are compared between the original and depressurized/repressurized samples. X-ray computed tomography (CT) images track how the gas-hydrate distribution changes in the hydrate-cemented sands due to the depressurization/repressurization process. Because depressurization-induced property changes can be substantial and are not easily predicted, particularly in water-saturated, hydrate-bearing sediment, maintaining pressure and temperature conditions throughout the core recovery and measurement process is critical for using laboratory measurements to estimate in situ properties.},
doi = {},
url = {https://www.osti.gov/biblio/934990}, journal = {Journal of Geophysical Research},
issn = {0148-0227},
number = B07102,
volume = 113,
place = {United States},
year = {2008},
month = {6}
}