Multi-field Coupling Simulation of Impact of Temperature and Density of Heat Injection Well on Carbon Budget during Hydrate Exploitation in Qilian Mountain Permafrost Region  

作　　者：Zhenhua Han Ruirui Li Luqing Zhang Jian Zhou Song Wang 

机构地区：[1]Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,China [2]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing,100029,China [3]Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing,100124,China

出　　处：《Journal of Earth Science》2024年第6期1934-1943,共10页地球科学学刊（英文版）

基　　金：supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0904);the National Natural Science Foundation of China(Nos.42107190,41972287 and 42277144)。

摘　　要：Permafrost regions of Qilian Mountains in China are rich in gas hydrate resources.Once greenhouse gases in deep frozen layer are released into the atmosphere during hydrate mining,a series of negative consequences occur.This study aims to evaluate the impact of hydrate thermal exploitation on regional permafrost and carbon budgets based on a multi-physical field coupling simulation.The results indicate that the permeability of the frozen soil is anisotropic,and the low permeability frozen layer can seal the methane gas in the natural state.Heat injection mining of hydrates causes the continuous melting of permafrost and the escape of methane gas,which transforms the regional permafrost from a carbon sink to a carbon source.A higher injection temperature concentrates the heat and causes uneven melting of the upper frozen layer,which provides a dominant channel for methane gas and results in increased methane emissions.However,dense heat injection wells cause more uniform melting of the lower permafrost layer,and the melting zone does not extend to the upper low permeability formation,which cannot provide advantageous channels for methane gas.Therefore,a reasonable and dense number of heat injection wells can reduce the risk of greenhouse gas emissions during hydrate exploitation.

关 键 词：PERMAFROST gas hydrates carbon budget methane emissions greenhouse gases environmental effects multi-field coupling SIMULATION 

分 类 号：TE37[石油与天然气工程—油气田开发工程]