Article
Thermodynamics
Bao-Can Dong, Peng Xiao, Yi-Fei Sun, Jing-Yu Kan, Ming-Ke Yang, Xiao-Wan Peng, Chang-Yu Sun, Guang-Jin Chen
Summary: This study analyzed the evolution and geological stability of hydrate deposits in the South China Sea during depressurization using a numerical model. The analysis also determined the gas-water production. The findings provide important insights for the exploitation of marine heterogeneous hydrates.
Article
Thermodynamics
Yongchang Feng, Lin Chen, Yuki Kanda, Anna Suzuki, Atsuki Komiya, Shigenao Maruyama
Summary: Artificial fractures in methane hydrate reservoirs can significantly improve hydrate dissociation and gas production efficiency, particularly in the early depressurization stage. Higher fracture permeability may shorten the economical production stage but lead to higher production rates. Furthermore, fractures facilitate the flow of hot water into the sediment, enhancing production efficiency during the economical production stage.
Article
Engineering, Marine
Xuyang Guo, Yan Jin, Jingyu Zi, Jiaying Lin, Bolong Zhu, Qian Wen, Qi Jing
Summary: Sand production is a significant challenge in the exploitation of methane hydrates, affecting gas productivity. This study presents a numerical model that describes the coupled thermal-hydraulic-mechanical-chemical responses and sand production patterns during horizontal well depressurization in methane-hydrate-bearing sediments. The results show the spatial and temporal evolution patterns of multi-physical fields and highlight the sensitivity of gas and sand production rates to various parameters.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Thermodynamics
Jidong Zhang, Zhenyuan Yin, Qingping Li, Shuaijun Li, Yi Wang, Xiao-Sen Li
Summary: Methane hydrates are considered as a future energy source with abundant resources and high energy density. The fluid production and thermal response of two types of hydrate-bearing sediments (excess-gas and excess-water) under controlled depressurization are still unclear. This study examines the hydrate dissociation kinetics and fluid production behavior in these sediments to shed light on optimizing production strategies for future field production trials.
Article
Chemistry, Multidisciplinary
Taehun Lee, Joo Yong Lee, Taewoong Ahn, Han Am Son
Summary: The cyclic depressurization method can significantly enhance geomechanical stability and increase gas production. It was found that by utilizing different bottomhole pressure and production time during depressurization, cumulative gas production can be greatly improved, while maintaining or even increasing stability in the subsurface.
APPLIED SCIENCES-BASEL
(2021)
Article
Energy & Fuels
Ziming Wang, Qilin Wang, Zhiqiang Fan, Wei Wei, Mengxin Li, Yanfeng Wang, Xuehua Huang, Yongchen Song, Dayong Wang
Summary: This paper summarizes classical and popular permeability models associated with hydrate dissociation and demonstrates an equivalency and replaceability relationship between different permeability models through systematic numerical sensitivity analysis, providing a basis for simplifying the selection of permeability models.
Article
Energy & Fuels
Yongmao Hao, Fan Yang, Jian Wang, Mingwu Fan, Shuxia Li, Shiwei Yang, Chuanming Wang, Xinhai Xiao
Summary: This paper investigates the impact of multilateral well exploitation technique on natural gas hydrates, utilizing simulation to study the mechanisms and changes in temperature, pressure, and hydrate concentration during gas production. Results show that the multilateral well technique significantly enhances the production capacity of hydrates.
Article
Energy & Fuels
Peixiao Mao, Jiaxin Sun, Fulong Ning, Lin Chen, Yizhao Wan, Gaowei Hu, Nengyou Wu
Summary: The study demonstrates that in inclined hydrate reservoirs, placing a single horizontal production well in the structural low can increase gas and water production; production performance in upper sandy reservoir and middle muddy reservoir are sensitive to the layout of production wells.
Article
Thermodynamics
Hongxing Du, Yiqun Zhang, Bo Zhang, Shouceng Tian, Gensheng Li, Panpan Zhang
Summary: This study found that hydrates generated through CO2 injection can inhibit methane hydrate decomposition, and delayed injections can increase cumulative yields. Additionally, CO2 injection can restore reservoir pressure and mitigate formation subsidence. The combination of CO2 injection in multilateral wells can increase hydrate production while maintaining formation stability. This research offers a new approach for commercial hydrate exploitation and presents a new possibility for using CO2 to address climate change.
Article
Engineering, Marine
Jingsheng Lu, Guangrong Jin, Dongliang Li, Deqing Liang, Yong He, Lingli Shi, Yiqun Zhang, Youming Xiong
Summary: This study conducted numerical simulation on sand production in hydrate-bearing sediments (HBS) exploitation. It found that the sand in the sediment is affected by pressure release during mining, leading to radial displacement and sand production. The balance between fluid driving force and radial displacement is crucial to sand production in HBS.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Shang Shilong, Gu Lijuan, Lu Hailong
Summary: The study of industrial exploitation of natural gas hydrate has progressed with production tests in permafrost and offshore regions, indicating that depressurization and multi-well production can improve gas production efficiency.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2021)
Article
Energy & Fuels
Qingping Li, Shuxia Li, Shuyue Ding, Zhenyuan Yin, Lu Liu, Shuaijun Li
Summary: In this study, a THMC numerical model was developed to simulate the gas productivity and reservoir stability of natural gas hydrate reservoirs. The simulation results showed that CO2 exchange promotes the dissociation of NGH and increases the production of gas and water while reducing reservoir subsidence.
Article
Energy & Fuels
Faling Yin, Yonghai Gao, Ye Chen, Baojiang Sun, Shaoqiang Li, Danshi Zhao
Summary: Gas hydrates-bearing shaly silt reservoirs have high reserves and low permeability. The trial production test in the South China Sea shows that horizontal wells have promising prospects for exploiting these hydrate reservoirs. However, the long-term gas production behavior is still unknown. Based on trial production data, the study investigates the optimization of depressurization schemes and reservoir selection to improve gas production efficiency, as well as the influence of compaction on gas production rate attenuation and reservoir stability.
Article
Geochemistry & Geophysics
Wang WenBo, Liu Xiao, Cui Wei, Xiao JiaQi
Summary: The study established a mathematical model of gas hydrate reservoir and solved it using finite difference method to investigate the decompression process. The results showed that during depressurization, a pressure drop funnel forms around the wellbore, leading to decomposition of hydrate near the wellbore, decrease in hydrate saturation, and increase in permeability. The decomposition transition zone moves outward and its width gradually stabilizes with production time, while the main control parameters include production well pressure, initial hydrate saturation, absolute permeability, and hydrate decomposition kinetic constants.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2021)
Article
Thermodynamics
Yilong Yuan, Ye Gong, Tianfu Xu, Huixing Zhu
Summary: In this study, a coupled simulator was developed to investigate the thermo-hydro-mechanical responses of offshore hydrate reservoirs. The results showed that the geomechanical response had a negative impact on the flow, and depressurization caused an increase in shear stress and vertical compaction in the reservoir. The reservoir heterogeneity led to non-uniform dissociation of hydrates and changes in effective stress. The findings of this study are helpful for designing safe hydrate production schemes in the future.