Tri-Axial Shear Tests on Hydrate-Bearing Sediments during Hydrate Dissociation with Depressurization

• Published in: Energies
• Main Authors: Li, Dongliang, Wu, Qi, Wang, Zhe, Lu, Jingsheng, Liang, Deqing, Li, Xiaosen
• Format: Report
• Language: English
• Published: MDPI 2018
• Subjects: Energy & Fuels; tri-axial shear test; hydrate-bearing sediments; depressurization; hydrate disassociation; METHANE HYDRATE; MECHANICAL-PROPERTIES; SAND; PRESSURE; STRENGTH; BEHAVIOR; Methane hydrate
• Online Access: http://ir.gig.ac.cn/handle/344008/39555; https://doi.org/10.3390/en11071819

A series of tri-axial shear tests were carried out to determine the stress and strain characteristics, as well as the volume deformation of methane hydrate-bearing sediments during gas hydrate dissociation. An innovative type of depressurization was adopted with a high-pressure and low-temperature tri-axial apparatus. Results show that: (1) decrease in pore pressure during the shear process may result in the failure of hydrate-bearing sediments, but they did not collapse completely due to high effective confining pressure; (2) depressurization leads to the contraction of volumetric strain and the ultimate deformation shows no difference compared to that prior depressurization; (3) high saturation hydrate-bearing sediments were more sensitive to depressurization, which could be due to the methane hydrate acting as a skeleton structure at some sites when the pore hydrates' saturation is high.