Natural hydrate-bearing sediments: Physical properties and characterization techniques
An extensive amount of natural gas trapped in the subsurface is found as methane hydrate. A fundamental understanding of natural hydrate-bearing sediments is required to engineer production strategies and to assess the risks hydrates pose to global climate change and large-scale seafloor destabiliza...
Main Author: | |
---|---|
Other Authors: | , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Georgia Institute of Technology
2014
|
Subjects: | |
Online Access: | http://hdl.handle.net/1853/52186 |
id |
ftgeorgiatech:oai:smartech.gatech.edu:1853/52186 |
---|---|
record_format |
openpolar |
spelling |
ftgeorgiatech:oai:smartech.gatech.edu:1853/52186 2023-05-15T17:11:55+02:00 Natural hydrate-bearing sediments: Physical properties and characterization techniques Dai, Sheng Santamarina, J. Carlos Civil and Environmental Engineering Frost, J. David Waite, William Burns, Susan E. Huber, Christian 2014-08-27T13:32:41Z application/pdf http://hdl.handle.net/1853/52186 en_US eng Georgia Institute of Technology http://hdl.handle.net/1853/52186 Methane hydrate Hydrate-bearing sediments Nucleation Hydrate morphology Water retention curve Network model simulation Clay Frozen sand Creep Coda wave interferometry Sampling disturbance Pressure core technology P-wave Hydraulic conductivity Pore water sampling Text Dissertation 2014 ftgeorgiatech 2023-03-27T17:54:04Z An extensive amount of natural gas trapped in the subsurface is found as methane hydrate. A fundamental understanding of natural hydrate-bearing sediments is required to engineer production strategies and to assess the risks hydrates pose to global climate change and large-scale seafloor destabilization. This thesis reports fundamental studies on hydrate nucleation, morphology and the evolution of unsaturation during dissociation, followed by additional studies on sampling and pressure core testing. Hydrate nucleation is favored on mineral surfaces and it is often triggered by mechanical vibration. Continued hydrate crystal growth within sediments is governed by capillary and skeletal forces; hence, the characteristic particle size d10 and the sediment burial depth determine hydrate morphologies in natural sediments. In aged hydrate-bearing sand, Ostwald ripening leads to patchy hydrate formation; the stiffness approaches to the lower bound at low hydrate saturation and the upper bound at high hydrate saturation. Hydrate saturation and pore habit alter the pore size variability and interconnectivity, and change the water retention curve in hydrate-bearing sediments. The physical properties of hydrate-bearing sediments are determined by the state of stress, porosity, and hydrate saturation. Furthermore, hydrate stability requires sampling, handling, and testing under in situ pressure, temperature, and stress conditions. Therefore, the laboratory characterization of natural hydrate-bearing sediments faces inherent sampling disturbances caused by changes in stress and strain as well as transient pressure and temperature changes that affect hydrate stability. While pressure core technology offers unprecedented opportunities for the study of hydrate-bearing sediments, careful data interpretation must recognize its inherent limitations. Ph.D. Doctoral or Postdoctoral Thesis Methane hydrate Georgia Institute of Technology: SMARTech - Scholarly Materials and Research at Georgia Tech |
institution |
Open Polar |
collection |
Georgia Institute of Technology: SMARTech - Scholarly Materials and Research at Georgia Tech |
op_collection_id |
ftgeorgiatech |
language |
English |
topic |
Methane hydrate Hydrate-bearing sediments Nucleation Hydrate morphology Water retention curve Network model simulation Clay Frozen sand Creep Coda wave interferometry Sampling disturbance Pressure core technology P-wave Hydraulic conductivity Pore water sampling |
spellingShingle |
Methane hydrate Hydrate-bearing sediments Nucleation Hydrate morphology Water retention curve Network model simulation Clay Frozen sand Creep Coda wave interferometry Sampling disturbance Pressure core technology P-wave Hydraulic conductivity Pore water sampling Dai, Sheng Natural hydrate-bearing sediments: Physical properties and characterization techniques |
topic_facet |
Methane hydrate Hydrate-bearing sediments Nucleation Hydrate morphology Water retention curve Network model simulation Clay Frozen sand Creep Coda wave interferometry Sampling disturbance Pressure core technology P-wave Hydraulic conductivity Pore water sampling |
description |
An extensive amount of natural gas trapped in the subsurface is found as methane hydrate. A fundamental understanding of natural hydrate-bearing sediments is required to engineer production strategies and to assess the risks hydrates pose to global climate change and large-scale seafloor destabilization. This thesis reports fundamental studies on hydrate nucleation, morphology and the evolution of unsaturation during dissociation, followed by additional studies on sampling and pressure core testing. Hydrate nucleation is favored on mineral surfaces and it is often triggered by mechanical vibration. Continued hydrate crystal growth within sediments is governed by capillary and skeletal forces; hence, the characteristic particle size d10 and the sediment burial depth determine hydrate morphologies in natural sediments. In aged hydrate-bearing sand, Ostwald ripening leads to patchy hydrate formation; the stiffness approaches to the lower bound at low hydrate saturation and the upper bound at high hydrate saturation. Hydrate saturation and pore habit alter the pore size variability and interconnectivity, and change the water retention curve in hydrate-bearing sediments. The physical properties of hydrate-bearing sediments are determined by the state of stress, porosity, and hydrate saturation. Furthermore, hydrate stability requires sampling, handling, and testing under in situ pressure, temperature, and stress conditions. Therefore, the laboratory characterization of natural hydrate-bearing sediments faces inherent sampling disturbances caused by changes in stress and strain as well as transient pressure and temperature changes that affect hydrate stability. While pressure core technology offers unprecedented opportunities for the study of hydrate-bearing sediments, careful data interpretation must recognize its inherent limitations. Ph.D. |
author2 |
Santamarina, J. Carlos Civil and Environmental Engineering Frost, J. David Waite, William Burns, Susan E. Huber, Christian |
format |
Doctoral or Postdoctoral Thesis |
author |
Dai, Sheng |
author_facet |
Dai, Sheng |
author_sort |
Dai, Sheng |
title |
Natural hydrate-bearing sediments: Physical properties and characterization techniques |
title_short |
Natural hydrate-bearing sediments: Physical properties and characterization techniques |
title_full |
Natural hydrate-bearing sediments: Physical properties and characterization techniques |
title_fullStr |
Natural hydrate-bearing sediments: Physical properties and characterization techniques |
title_full_unstemmed |
Natural hydrate-bearing sediments: Physical properties and characterization techniques |
title_sort |
natural hydrate-bearing sediments: physical properties and characterization techniques |
publisher |
Georgia Institute of Technology |
publishDate |
2014 |
url |
http://hdl.handle.net/1853/52186 |
genre |
Methane hydrate |
genre_facet |
Methane hydrate |
op_relation |
http://hdl.handle.net/1853/52186 |
_version_ |
1766068664558157824 |