Experimental Investigation of the Mechanical Properties of Methane Hydrate–Bearing Sediments under High Effective Confining Pressure
Experimental Investigation of the Mechanical Properties of Methane Hydrate–Bearing Sediments under High Effective Confining Pressure
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DOI：
10.1061/(asce)gt.1943-5606.0002728
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发表时间：
2022-03
影响因子：
3.9
通讯作者：
Jialin Xu;Cheng-shun Xu;N. Yoshimoto;M. Hyodo;S. Kajiyama;Lingxia Huang
中科院分区：
文献类型：
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作者：
Jialin Xu;Cheng-shun Xu;N. Yoshimoto;M. Hyodo;S. Kajiyama;Lingxia Huang
采用降压方法可引起含水储层有效应力的显著增加。对不同水合物饱和度的含水沉积物进行了排水三轴剪切试验，研究了其在20 MPa有效围压下的力学特性。结果表明：高压剪切过程中，基质砂颗粒破碎明显，水合物饱和度对颗粒破碎程度影响不显著；随着有效围压的增大，含水试样的应力-应变曲线由应变软化向应变硬化转变。随着围应力的增大，沉积物的峰值应力比和内摩擦角逐渐减小并趋于恒定，而含水沉积物的黏聚力呈增大趋势。在低至高有效围压作用下，空间含水沉积物的临界状态线与相同水合物饱和度下的正常固结线相交。此外，随着水合物饱和度的增加，CSL向上移动并顺时针旋转。
A significant increase in effective stress can be induced in hydrate-bearing reservoirs when the depressurization method is applied. A series of drained triaxial shear tests were performed on hydrate-bearing sediments with various hydrate saturations to investigate their mechanical characteristics under effective confining pressures of up to 20 MPa. The results show that significant particle crushing of the host sand occurs during shearing under high pressures, and there is no remarkable effect of hydrate saturation on the degree of particle breakage. As the effective confining pressure increases, the stress–strain curves of the hydrate-bearing specimen transformed from strain-softening to strain-hardening. The peak stress ratio and internal friction angle of the sediments gradually decrease and tend to be constant with the increased confining stress, whereas the cohesion in hydrate-bearing sediments exhibits an increasing tendency. The critical state line (CSL) of hydrate-bearing sediments in thespace under low-to-high effective confining pressures intersects with the normal consolidation line under the same hydrate saturation. Furthermore, the CSL moves upward and rotates clockwise as the hydrate saturation increases.