Article
Engineering, Geological
Zeshao You, Yun Hao, Wenkang Hu, Shi Shen, Peng Wu, Yanghui Li
Summary: This study investigates the mechanical behaviors of sandy sediments containing methane hydrate (MH) under excess gas and excess water conditions. The study finds that the influence of MH saturation and effective confining stress on sediment properties are coupled, higher MH saturation leads to strain softening behavior but is hindered by high effective confining stress. The samples with MH exhibit higher stiffness, failure strength, and strain softening tendency under excess gas conditions compared to excess water conditions.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Marine
Lin Dong, Hualin Liao, Yanlong Li, Qingguo Meng, Gaowei Hu, Jintang Wang, Nengyou Wu
Summary: This study analyzed the mechanical properties of clayey-silt samples containing tetrahydrofuran hydrate through triaxial shear tests. The stress-strain curves exhibited strain-hardening under shearing and could be divided into elastic deformation, transitional stage, and plastic deformation. The cohesion increased with hydrate saturation. Calculation models were proposed to evaluate failure strengths and Young's modulus using experimental data.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Marine
Meng Li, Hengjie Luan, Yujing Jiang, Sunhao Zhang, Qinglin Shan, Wei Liang, Xianzhuang Ma
Summary: This study used the discrete element simulation program to conduct direct shear simulations of natural gas hydrate-bearing sediment specimens with different saturations, revealing their shear mechanical characteristics and evolution laws. The results show that the peak intensity of natural gas hydrate-bearing sediments increases with the increase in normal stress and hydrate saturation, with sand particles playing a major role in shear resistance.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Thermodynamics
Qilin Wang, Ziming Wang, Peng Li, Yongchen Song, Dayong Wang
Summary: This study establishes a coupling model for gas production in the Shenhu hydrate reservoir and finds that the effective stress rapidly increases during field tests, leading to seafloor subsidence, but remains mostly unchanged half a year later. The principal effective stress will not cause yield failure, ensuring long-term production security. Ignoring mechanical behavior can double the predicted production performance indices, but this can be counterbalanced by uncertainty in reservoir permeability. Therefore, obtaining measurement data of formation deformation and reservoir permeability is crucial.
Article
Computer Science, Interdisciplinary Applications
Xiaofeng Dou, Zhichao Liu, Fulong Ning, Yanlong Li, Xiaodong Li, Yingjie Zhao, Wei Hu, Deli Gao
Summary: This study presents a novel approach based on the discrete element method (DEM) to describe the mechanical weakening of cementing-type gas hydrate-bearing sandy sediments (GHBSSs) during hydrate dissociation. The DEM model successfully captures the mechanical weakening behaviors of GHBSSs, and a fitting equation is obtained to describe the relationship among peak strength, initial hydrate saturation, and hydrate dissociation ratio. This study is valuable for evaluating the stability of GHBSSs during hydrate production.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Thermodynamics
Yanghui Li, Wenkang Hu, Haoran Tang, Peng Wu, Tao Liu, Zeshao You, Tao Yu, Yongchen Song
Summary: Natural gas hydrate (NGH) is a promising and clean energy source. The development of permafrost hydrate-bearing sediment (HBS) has lower costs, and understanding the mechanical properties is crucial for safe exploitation assessment.
Article
Polymer Science
Jianlong Wang, Jinsheng Sun, Hang Bian, Qibing Wang, Zhenbo Feng, Cheng Lu, Han Ren, Rongchao Cheng, Jintang Wang, Ren Wang
Summary: Natural gels have attracted global research attention for their greenness, environmental-friendliness, and good hydrate inhibition performance. This study evaluated the inhibition performance of xanthan gum and pectin on hydrate nucleation and growth in sediment environments and revealed the internal inhibition mechanisms. The study also investigated the effects of natural gels on sediment dispersion stability and low-temperature fluid rheology.
Article
Engineering, Geological
Marwan Khashila, Mahmoud N. Hussien, Mourad Karray, Mohamed Chekired
Summary: The study compared the results of cyclic triaxial (CTX) and direct simple shear (DSS) tests under stress and strain-controlled conditions. It found that the liquefaction potential curves of cyclic stress-controlled CTX testing results are usually higher than those of direct simple shear (TxSS) testing results.
Article
Thermodynamics
Lin Dong, Yizhao Wan, Yanlong Li, Hualin Liao, Changling Liu, Nengyou Wu, Yuri Leonenko
Summary: This study developed a 3-D coupled thermal-hydro-chemical model to investigate the drilling fluid invasion process and dynamic responses of gas hydrate reservoirs. The invasion characteristics mainly depend on drilling fluid pressure and permeability, while temperature affects hydrate dissociation. Fluid-loss velocity increases slowly due to the increase in permeability induced by hydrate dissociation after an initial sharp decrease in invasion.
Article
Geosciences, Multidisciplinary
Jun Pei, Na Wei, Boning Zhang, Jinzhou Zhao, Bjorn Kvamme, Richard B. B. Coffin, Haitao Li, Ruiling Bai
Summary: This study investigates the effect of drilling fluid invasion on the strength behaviors of hydrate-bearing sediments. The findings show that with increasing hydrate saturation, the sediments transition from strain hardening to strain softening. Furthermore, drilling fluid invasion significantly affects the peak strength and modulus of the sediments.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Engineering, Geological
Hua Du, Huie Chen, Qing Wang, Yonggui Luo, Fansheng Kong, Bin Shi
Summary: The mechanical properties of heterogeneous hydrate-bearing sediments have significant engineering implications. In this study, the effects of hydrate-bearing layer thickness and angle on stress-strain behavior and strength parameters were investigated. It was found that increasing layer thickness and decreasing angle resulted in decreased strain-hardening and varying failure strength.
ENGINEERING GEOLOGY
(2023)
Article
Energy & Fuels
Zihua Shao, Jintang Wang, Kaihe Lv, Zonglun Wang, Yujing Bai, Ren Wang, Jinsheng Sun
Summary: A low-field NMR-based experimental method is developed to characterize the hydrate dissociation inhibition effect during fluid invasion to hydrate-bearing sediment. The presence of hydrate dissociation inhibitor significantly reduces invasion area and keeps invasion fluid saturation at 30% instead of 80% compared to water. Experimental techniques are used to reveal the mechanism of hydrate dissociation inhibition.
Article
Chemistry, Multidisciplinary
Xiaofang Lv, Yang Liu, Shidong Zhou, Bohui Shi, Kele Yan
Summary: The study investigates the decomposition mechanism of hydrate slurry and proposes that desorption of gas from the surface of decomposed particles may be the main cause of particle coalescence. A comprehensive kinetic model considering influencing factors such as intrinsic kinetics, heat, and mass transfer is proposed, using fugacity difference as the driving force for hydrate decomposition. The model integrates heat and mass transfer effects and can describe trends in gas release and dissociation rate in experimental flow systems.
Review
Green & Sustainable Science & Technology
Mingtao Chen, Yanlong Li, Sukru Merey, Nengyou Wu, Qiaobo Hu, Yajuan Zhang, Lin Dong, Guigang Yu, Haiyang Jiang
Summary: This study comprehensively reviewed the feasibility and mechanical research progress of various experimental methods for assessing the mechanical behavior of hydrate-bearing sediments. The precision and sample size of each method were compared and analyzed, and the limitations and challenges of current methods were discussed. Future development directions were proposed to improve the understanding of the mechanical behavior of hydrate-bearing sediments.
Article
Engineering, Geological
Rui Kong, Ergun Tuncay, Resat Ulusay, Xiwei Zhang, Xia-Ting Feng
Summary: The study investigated the different failure characteristics of volcanic rock under high-stress conditions, revealing various failure modes under different stress states. It found that the rock exhibited unstable brittle failure under 1-D and 2-D compression, stable failure under axisymmetric triaxial stress, and localized shear failure under a three-dimensional differential stress state. The research also assessed the effect of sigma(2) on unstable failure based on energy release and cracking propagation.
ENGINEERING GEOLOGY
(2021)
Article
Energy & Fuels
Xiangyu Fang, Dianheng Yang, Fulong Ning, Linjie Wang, Zhichao Liu, Yanjiang Yu, Wenwei Xie, Hongfeng Lu, Yanlong Li, Meng Xu
Summary: The gas-water-sand production behaviors and coupling reservoir subsidence characteristics of clayey silt hydrate reservoirs with different clay contents were studied. The results showed that the sand production reached its maximum when the clayey content was 20%, and it significantly increased during hydrate dissociation but decreased after dissociation.
Review
Engineering, Marine
Qiang Chen, Nengyou Wu, Changling Liu, Changchun Zou, Yang Liu, Jianye Sun, Yanlong Li, Gaowei Hu
Summary: Natural gas hydrate is widely distributed in marine environments and has great energy potential. Resistivity is a reliable method for deriving the characteristics of gas hydrate reservoirs, although it is influenced by the anisotropy of the reservoirs and drilling technology. The specific resistivity change depends on sediment lithology and hydrate saturation. Clay minerals are a limiting factor for accurately estimating hydrate saturations using in situ resistivity measurements. There is a need for widely representative models to correct for errors in resistivity measurements. More complex resistivity measurements may provide additional electrical response information on different gas hydrate systems.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Jianye Sun, Xiluo Hao, Chengfeng Li, Nengyou Wu, Qiang Chen, Changling Liu, Yanlong Li, Qingguo Meng, Li Huang, Qingtao Bu
Summary: CH4/CO2 replacement is significant for the exploitation of natural gas hydrate resources and CO2 storage. This study investigated the distribution characteristics of CH4 and CO2 during and after replacement in hydrate-bearing sediments, and summarized the steps of pore-scale CH4/CO2 replacement process.
Article
Computer Science, Interdisciplinary Applications
Xiaofeng Dou, Zhichao Liu, Fulong Ning, Yanlong Li, Xiaodong Li, Yingjie Zhao, Wei Hu, Deli Gao
Summary: This study presents a novel approach based on the discrete element method (DEM) to describe the mechanical weakening of cementing-type gas hydrate-bearing sandy sediments (GHBSSs) during hydrate dissociation. The DEM model successfully captures the mechanical weakening behaviors of GHBSSs, and a fitting equation is obtained to describe the relationship among peak strength, initial hydrate saturation, and hydrate dissociation ratio. This study is valuable for evaluating the stability of GHBSSs during hydrate production.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Thermodynamics
Lin Dong, Yanlong Li, Nengyou Wu, Yizhao Wan, Hualin Liao, Huajian Wang, Yajuan Zhang, Yunkai Ji, Gaowei Hu, Yuri Leonenko
Summary: Multi-well systems can increase productivity of natural gas hydrate (NGH) production by enlarging the drainage area. The double-well system is fundamental for understanding and formulating field strategies for extracting gas from hydrate-bearing sediments. A three-dimensional model is developed to describe double-well production characteristics and analyze well-deployment strategies. The productivity of the double-well system is significantly higher than that of a single well, and the well spacing is the key variable for the system's performance.
Article
Thermodynamics
Xinxin Cao, Jiaxin Sun, Fanfan Qin, Fulong Ning, Peixiao Mao, Yuhang Gu, Yanlong Li, Heen Zhang, Yanjiang Yu, Nengyou Wu
Summary: Multilateral well technique is a promising approach to enhance gas recovery in heterogeneous hydrate reservoirs. A 3D numerical model is proposed to predict the production performance of hydrate reservoirs using multilateral wells. The optimal deployment location and branch length for dual-branch and quad-branch scenarios are determined. Dual-lateral wells have the most favorable yield-increasing effects compared to vertical wells. Well interference between branches may exist and worsens with an increase in branch number. This research provides insight into the industrialized co-production of hydrate and free gas.
Article
Geochemistry & Geophysics
Yang Liu, Changchun Zou, Qiang Chen, Jinhuan Zhao, Yanlong Li, Jianye Sun, Changling Liu, Cheng Peng, Caowei Wu
Summary: This study developed a simulation framework for monitoring gas hydrates using cross-hole electrical resistivity tomography (CHERT) and verified its effectiveness through numerical and physical experiments. The results showed that proper electrode layouts can yield satisfactory monitoring results, which is of great significance for gas hydrate production.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Engineering, Marine
Mingtao Chen, Yanlong Li, Penghui Zhang, Guigang Yu, Zhun Zhang, Yajuan Zhang, Haiyang Jiang, Bin Gong, Nengyou Wu
Summary: This study investigates the deformation mechanisms of hydrate-bearing sediments with laminar hydrate distribution through numerical simulations. The results indicate that the hydrate saturation and thickness ratio significantly affect the mechanical behavior of the sediments.
Article
Instruments & Instrumentation
Qiaobo Hu, Yanlong Li, Xiaofeng Sun, Mingtao Chen, Qingtao Bu, Bin Gong
Summary: In this study, a novel device is proposed to test the time-dependent deformation and ultrasonic response of hydrate-bearing sediment (HBS) under high-pressure and low-temperature conditions. The device allows control of four pressures and analysis of stress-strain relationships and ultrasonic data to determine the macroscopical failure and microcosmical creep deformation law of the samples. Preliminary experiments have verified the applicability of the device. This method is significant for field observation of reservoir failure during hydrate exploitation using geophysical techniques.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Editorial Material
Energy & Fuels
Lin Dong, Nengyou Wu, Yajuan Zhang, Hualin Liao, Gaowei Hu, Yanlong Li
Summary: Based on test data, an improved Duncan-Chang model is established in this paper to characterize the strength and deformation of hydrate reservoirs in the South China Sea. This model accurately describes strainhardening characteristics and estimates failure strength with high fitting accuracy. The study provides a simple and applicable method for estimating the mechanical behaviors of hydrate reservoirs, supporting the prevention and control of geological risks during hydrate exploitation in the South China Sea.
ADVANCES IN GEO-ENERGY RESEARCH
(2023)
Article
Thermodynamics
Jiaxin Sun, Fanfan Qin, Fulong Ning, Yuhang Gu, Yanlong Li, Xinxin Cao, Peixiao Mao, Tianle Liu, Shunbo Qin, Guosheng Jiang
Summary: By comparing the production behaviors of different well pattern designs through numerical simulation, the optimal well spacing was determined. The results showed that a relatively longer well spacing in homogeneous sediments with the same ultra-low permeability leads to lower cumulative gas recovery, but the opposite is observed after increasing the formation permeability. The exponential model can describe the relationship between cumulative gas recovery and well spacing, and the minimum radius of curvature method can be used to determine the optimal well spacing. For relatively high-permeability reservoirs confined by ultra-low permeability burdens, gas recovery increases in both well patterns, but this stimulation may gradually weaken in the long-term production. The ideal well spacing can be suggested by comparing the cumulative gas recovery during each stage, providing valuable reference for future applications.
Article
Thermodynamics
Lin Dong, Nengyou Wu, Yuri Leonenko, Yizhao Wan, Hualin Liao, Gaowei Hu, Yanlong Li
Summary: Evaluation of interactions among multiple physical fields in natural gas hydrate reservoirs is crucial for risk management during drilling fluid invasion. A coupled thermal-hydraulic-mechanical model is established to characterize stress states and invasion-induced deformation, reflecting the effect of borehole shapes and drilling operations. The results reveal that drilling fluid invasion causes stress and strain concentrations around the wellbore, and stress states depend on the borehole shapes and invasion degree. Coupling effects of invasion and phase transition under various stresses can lead to unavoidable deformation and stress changes. Therefore, coupled analysis of geomechanical behaviors is indispensable for risk control in drilling hydrate reservoirs.
Article
Energy & Fuels
Jie Chen, Zhengcai Zhang, Yongchao Hao, Daniel Porfirio Luis Jimenez, Jiafang Xu, Nengyou Wu, Fulong Ning, Bin Fang, Jun Zhang, Jianye Sun, Xiluo Hao, Qingguo Meng, YanLong Li, Yizhao Wan, Chanjuan Liu, Gaowei Hu
Summary: The formation and dissociation of gas hydrate can be influenced by electrostatic fields, making it a potential technology with great application value in hydrate exploitation, prevention, and related technologies. The molecular dynamics simulation revealed that the migration and destruction of ions in the hydrate are influenced by the strength of the electrostatic field. The insights gained from this study are beneficial for the application of electrostatic field in hydrate mining and safety of oil and gas pipeline transportation.
