Investigation of Macro-Meso Mechanical Properties of Cemented Hydrate-Bearing Sandy Sediments in the South China Sea Using Discrete Element Method

Sandy hydrate reservoirs are considered an ideal target for the extraction of marine natural gas hydrates (NGH). However, engineering geological risks, including reservoir sand production and seabed subsidence during the extraction process, present a significant challenge. In 2019, China discovered...

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Bibliographic Details
Published in:Energy Science & Engineering
Main Authors: Wang, Zhigang, Zhang, Xuran, Zhang, Yan, Yuan, Qingmeng, Yang, Lin, 张旭辉, Wu, Xuemin, Liang, Qianyong
Format: Report
Language:English
Published: 2025
Subjects:
discrete element method
hydrate-bearing sandy sediments
hydrate cementation
hydrate saturation
shear behavior
ARTIFICIAL METHANE-HYDRATE
GAS HYDRATE
NUMERICAL SIMULATIONS
FLEXIBLE MEMBRANE
GRANULAR MATERIAL
DEM SIMULATIONS
TRIAXIAL TEST
STRENGTH
ENERGY
Energy & Fuels
Q3
Methane hydrate
Online Access:http://dspace.imech.ac.cn/handle/311007/100232
http://dspace.imech.ac.cn/handle/311007/100233
https://doi.org/10.1002/ese3.70047
Description
Summary:Sandy hydrate reservoirs are considered an ideal target for the extraction of marine natural gas hydrates (NGH). However, engineering geological risks, including reservoir sand production and seabed subsidence during the extraction process, present a significant challenge. In 2019, China discovered a high-concentration sandy NGH reservoir with favorable commercial development potential in the Qiongdongnan Basin of the South China Sea, establishing the region as a key focus for future exploration and development efforts. A thorough comprehension of macro-meso mechanical properties of this specific sandy NGH reservoir is essential for the safe and efficient extraction of hydrates. In this study, a novel method is proposed to calculate hydrate saturation of hydrate-bearing sandy sediments (HBSS) with hexagonal close-packed state. A series of undrained biaxial compression with flexible boundary show that hydrate cementation enhances the strength of the sample. However, an excessively high hydrate saturation is likely to induce strain softening, whereas an increase in confining pressure helps to mitigate strain softening. Hydrate cementation promotes the formation of abundant force chains. The inhomogeneous displacement, sliding, and relative rotation of the particles are the primary factors contributing to the formation of X-shaped shear bands, which is related to cemented bond breakage. The primary cause of hydrate cementation failure is tensile stress failure. External loading induces force chains to undergo buckling, fracturing, and restructuring, which governs fabric development. The research outcomes offer novel insights into the inhomogeneous deformation and macro-meso mechanical properties of HBSS at the particle-scale.

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