Geotechnical and geophysical properties of deep marine fine-grained sediments recovered during the second Ulleung Basin Gas Hydrate expedition, East Sea, Korea
Geotechnical and geophysical properties of deep marine fine-grained sediments recovered during the second Ulleung Basin Gas Hydrate expedition, East Sea, Korea
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DOI：
10.1016/j.marpetgeo.2013.05.009
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发表时间：
2013-11
影响因子：
4.2
通讯作者：
Hak-Sung Kim;G. Cho;J. Lee;Se-Joon Kim
中科院分区：
文献类型：
--
作者：
Hak-Sung Kim;G. Cho;J. Lee;Se-Joon Kim
研究了韩国东海郁陵盆地第二次天然气水合物勘探（UBGH2）中回收的最小扰动细粒海洋沉积物的岩土力学和地球物理性质。采用常规的实验室岩土工程试验方法，从岩土工程的角度对沉积物进行表征。根据统一土壤分类系统（USCS），沉积物以松散为主，属于高塑性粉质土；当有效应力增加（或孔隙水压力降低）时，它们表现出高压缩性，低水力导率和低固结系数（或压力扩散）。预计在研究地点采用降压方法生产天然气水合物将在生产孔周围造成大量的沉降和压实。由于含天然气水合物沉积物的剪切波速对应力状态的敏感性远低于不含天然气水合物的沉积物，因此可以通过测量的含天然气水合物沉积物的剪切波速数据来估计水合物的饱和程度。此外，通过比较沉积物的含水量、压缩性和电阻率，验证了沉积物中预先存在的天然气水合物。
This study investigates the geotechnical and geophysical properties of minimally disturbed fine-grained marine sediments recovered during the second Ulleung Basin Gas Hydrate expedition (UBGH2), East Sea, Korea. Conventional laboratory geotechnical engineering test methods were used to characterize the sediments from a geotechnical engineering perspective. The sediments were mostly uncompacted and classified as highly plastic silty soils according to the Unified Soil Classification System (USCS); they exhibited high compressibility when subjected to an increase in effective stress (or a decrease in pore water pressure), low hydraulic conductivities, and low coefficient of consolidation (or pressure diffusion). It is expected that the application of a depressurization method for gas hydrate production at the investigated sites would cause a significant amount of settlement and compaction around the production hole. Because the shear wave velocity of gas hydrate-bearing sediments is much less sensitive to the stress state and is much higher than that of sediments without gas hydrates, it is possible to estimate the degree of hydrate saturation from shear wave velocity data measured in gas hydrate-bearing sediments. In addition, the prior presence of gas hydrates in the sediments was verified through a comparison of water content, compressibility, and electrical resistivity of the sediments.