Volume change associated with formation and dissociation of hydrate in sediment
Lee, J. Y.
Santamarina, J. Carlos
Ruppel, Carolyn D.
MetadataShow full item record
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 subsidence of the ground surface over areas where methane might be produced from gas hydrate in the future. Experiments on sand, silts, and clay subject to different effective stress and containing different saturations of hydrate formed from dissolved phase tetrahydrofuran are used to systematically investigate the impact of gas hydrate formation and dissociation on bulk sediment volume. Volume changes in low specific surface sediments (i.e., having a rigid sediment skeleton like sand) are much lower than those measured in high specific surface sediments (e.g., clay). Early hydrate formation is accompanied by contraction for all soils and most stress states in part because growing gas hydrate crystals buckle skeletal force chains. Dilation can occur at high hydrate saturations. Hydrate dissociation under drained, zero lateral strain conditions is always associated with some contraction, regardless of soil type, effective stress level, or hydrate saturation. Changes in void ratio during formation-dissociation decrease at high effective stress levels. The volumetric strain during dissociation under zero lateral strain scales with hydrate saturation and sediment compressibility. The volumetric strain during dissociation under high shear is a function of the initial volume average void ratio and the stress-dependent critical state void ratio of the sediment. Other contributions to volume reduction upon hydrate dissociation are related to segregated hydrate in lenses and nodules. For natural gas hydrates, some conditions (e.g., gas production driven by depressurization) might contribute to additional volume reduction by increasing the effective stress.
Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 11 (2010): Q03007, doi:10.1029/2009GC002667.
Showing items related by title, author, creator and subject.
Santamarina, J. Carlos; Dai, Sheng; Terzariol, Marco; Jang, J.; Waite, William F.; Winters, William J.; Nagao, Jiro; Yoneda, Jun; Konno, Yoshihiro; Fujii, Tetsuya; Suzuki, K. (Elsevier, 2015-03-01)Natural hydrate-bearing sediments from the Nankai Trough, offshore Japan, were studied using the Pressure Core Characterization Tools (PCCTs) to obtain geomechanical, hydrological, electrical, and biological properties ...
Waite, William F.; Santamarina, J. Carlos; Cortes, Douglas D.; Dugan, Brandon; Espinoza, D. N.; Germaine, J.; Jang, J.; Jung, J. W.; Kneafsey, Timothy J.; Shin, H.; Soga, K.; Winters, William J.; Yun, T.-S. (American Geophysical Union, 2009-12-31)Methane gas hydrates, crystalline inclusion compounds formed from methane and water, are found in marine continental margin and permafrost sediments worldwide. This article reviews the current understanding of phenomena ...
Elevated gas hydrate saturation within silt and silty clay sediments in the Shenhu area, South China Sea Wang, Xiujuan; Hutchinson, Deborah R.; Wu, Shiguo; Yang, Shengxiong; Guo, Yiqun (American Geophysical Union, 2011-05-25)Gas hydrate saturations were estimated using five different methods in silt and silty clay foraminiferous sediments from drill hole SH2 in the South China Sea. Gas hydrate saturations derived from observed pore water ...