The response of temperature and pressure of hydrate reservoirs in the first gas hydrate production test in South China Sea

作     者：Qin, Xuwen Liang, Qianyong Ye, Jianliang Yang, Lin Qiu, Haijun Xie, Wenwei Liang, Jinqiang Lu, Jin'an Lu, Cheng Lu, Hailong Ma, Baojin Kuang, Zenggui Wei, Jiangong Lu, Hongfeng Kou, Beibei 

作者机构：China Geol Survey Guangzhou Marine Geol Survey Guangzhou 510075 Peoples R China China Geol Survey Gas Hydrate Engn Technol Ctr Guangzhou 510075 Peoples R China China Acad Geol Sci Inst Explorat Tech Langfang 065000 Peoples R China China Geol Survey Ctr Oil & Nat Gas Resource Explorat Beijing 100083 Peoples R China Peking Univ Beijing 100871 Peoples R China CNPC Offshore Engn Co Ltd Beijing 100102 Peoples R China 

出 版 物：《APPLIED ENERGY》 (实用能源)

年 卷 期：2020年第278卷

页      面：115649-115649页

核心收录：

学科分类：0820[工学-石油与天然气工程] 0817[工学-化学工程与技术] 08[工学] 0807[工学-动力工程及工程热物理] 

基　　金：Major Program of National Natural Science Foundation of China China Geological Survey [DD20190218, DD20190226] National Key R&D Program of China [2017YFC0307605] Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) [GML2019ZD0307] 

主　　题：Marine gas hydrate Temperature response Pore pressure response Depressurization production Secondary hydrate 

摘      要：The first offshore natural gas hydrate production test of China in 2017 has proved the feasibility of hydrate exploitation from clayey-silt reservoirs, which possesses the highest reservoirs than other types of hydrate resources. However, owing to the absence of monitoring wells in this production test, the hydrate dissociation behavior cannot be analyzed through pressure and temperature changes of hydrate reservoirs. This paper focuses on the simulation study on the detailed response of the temperature and pore pressure of hydrate reservoirs of Well SHSC-4 during the gas production by depressurization. Meanwhile, it highlights the analysis of favorable areas for the formation of secondary hydrates and the influence of the secondary hydrates on pressure and temperature field of hydrate reservoirs. The simulation results indicate that in the first 60 days, the hydrate reservoirs feature a dissociation radius of about 5 m, and the gas production from hydrate dissociation accounts for about 85%. After 1 year, 2 years and 5 years of hydrate exploitation, the influence radius of low-pressure area (10 MPa) is 15 m, 16 m and 17 m, respectively, suggesting that the hydrate reservoirs have higher gas production efficiency in the first year. Furthermore, the temperature and pressure of hydrate reservoirs are not favorable to the formation of secondary hydrates in the first 60 days. In long-term production, secondary hydrates are mainly formed at hydrate dissociation front. This can increase the pore pressure and further decrease the effective stress in the local areas of hydrate reservoirs, thus affecting mechanical stability of the local hydrate reservoirs.