Hydrate morphology : physical properties of sands with patchy hydrate saturation

View/ Open
Date
2012-11-14Author
Dai, Sheng
Concept link
Santamarina, J. Carlos
Concept link
Waite, William F.
Concept link
Kneafsey, Timothy J.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/5635As published
https://doi.org/10.1029/2012JB009667DOI
10.1029/2012JB009667Keyword
Analytical model; Gas hydrate; Hydrate pore habit; Hydrate-bearing sediments; Numerical model; Upper and lower boundsAbstract
The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.
Description
Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): B11205, doi:10.1029/2012JB009667.
Collections
Suggested Citation
Journal of Geophysical Research 117 (2012): B11205Related items
Showing items related by title, author, creator and subject.
-
A 2-D tomographic model of the Juan de Fuca plate from accretion at axial seamount to subduction at the Cascadia margin from an active source ocean bottom seismometer survey
Horning, Gregory W.; Canales, J. Pablo; Carbotte, Suzanne M.; Han, Shuoshuo; Carton, Helene; Nedimovic, Mladen R.; van Keken, Peter E. (John Wiley & Sons, 2016-08-14)We report results from a wide-angle controlled source seismic experiment across the Juan de Fuca plate designed to investigate the evolution of the plate from accretion at the Juan de Fuca ridge to subduction at the Cascadia ... -
Timescales and processes of methane hydrate formation and breakdown, with application to geologic systems
Ruppel, Carolyn D.; Waite, William F. (American Geophysical Union, 2020-06-04)Gas hydrate is an ice‐like form of water and low molecular weight gas stable at temperatures of roughly −10°C to 25°C and pressures of ~3 to 30 MPa in geologic systems. Natural gas hydrates sequester an estimated one sixth ... -
Volume change associated with formation and dissociation of hydrate in sediment
Lee, J. Y.; Santamarina, J. Carlos; Ruppel, Carolyn D. (American Geophysical Union, 2010-03-11)Gas hydrate formation and dissociation in sediments are accompanied by changes in the bulk volume of the sediment and can lead to changes in sediment properties, loss of integrity for boreholes, and possibly regional ...