Compressional and shear wave velocities in uncemented sediment containing gas hydrate
Compressional and shear wave velocities in uncemented sediment containing gas hydrate
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DOI：
10.1029/2005gl022607
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发表时间：
2005-05
影响因子：
5.2
通讯作者：
T. Yun;F. Francisca;J. Santamarina;C. Ruppel
中科院分区：
文献类型：
--
作者：
T. Yun;F. Francisca;J. Santamarina;C. Ruppel
沉积物中颗粒级天然气水合物形成的竞争性假设描述了孔隙填充、框架构建或胶结过程。在四氢呋喃水合物形成过程中，在低约束条件下对细粒砂岩的纵波（VP）和横波（VS）速度进行了新的测量和监测，结果表明，水合物在孔隙空间（可能在晶界处）成核并生长，对沉积物剪切刚度、VP和VS的影响有限，直到水合物浓度达到~ 40%时晶体开始与颗粒骨架相互作用。在较高的水合物浓度下，VS的增幅明显大于VP，这反映了试样剪切刚度的变化大于体积刚度的变化。结果表明，地震速度和/或它们的比值（VP/VS）对水合物的定位或水合物浓度的限制能力有限。
The competing hypotheses for gas hydrate formation at the particle scale in sediments describe processes of pore‐filling, frame‐building, or cementation. New measurements of compressional (VP) and shear wave (VS) velocities in fine‐grained sands subjected to low confinement and monitored during formation of tetrahydrofuran hydrate indicate that hydrate nucleates in the pore space (presumably at grain boundaries) and grows with limited impact on the sediment shear stiffness, VP, and VS until crystals begin to interact with the granular skeleton at ∼40% hydrate concentration. VS increases significantly more than VP at higher hydrate concentrations, reflecting larger changes in the specimen's shear stiffness than its bulk stiffness. The results indicate that seismic velocities and/or their ratio (VP/VS) have limited capability for locating hydrate or constraining hydrate concentrations.