热-力耦合作用下花岗岩粗糙裂隙渗透率演化规律  

Permeability Evolution of Granite with Rough Fracture Under Thermal-Mechanical Coupling

作　　者：袁益龙 唐佳伟 李鹏 何瑞敏 郭强 钟承昊 Yuan Yilong;Tang Jiawei;Li Peng;He Ruimin;Guo Qiang;Zhong Chenghao(State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,Beijing 102209,China;Key Laboratory of Groundwater Resources and Environment(Jilin University),Ministry of Education,Changchun 130021,China;Technology Research Institute,CHN Energy Shendong Coal Group Co.,Ltd.,Yulin 719315,Shaanxi,China)

机构地区：[1]煤炭开采水资源保护与利用国家重点实验室,北京102209 [2]地下水资源与环境教育部重点实验室(吉林大学),长春130021 [3]国家能源集团神东煤炭技术研究院,陕西榆林719315

出　　处：《吉林大学学报(地球科学版)》2025年第1期179-187,共9页Journal of Jilin University:Earth Science Edition

基　　金：国家自然科学基金项目(42372283);吉林省科技厅自然科学基金项目(20220101160JC)。

摘　　要：为研究热-力耦合作用对增强型地热系统热储裂隙渗透率演化的影响,利用含粗糙单裂隙的花岗岩试样,分别在加卸载围压为5~30 MPa,室温(25℃)、高温(150和180℃)条件下进行了流动-应力加卸载耦合实验,分析了应力加卸载引起的弹-塑性变形与裂隙渗透率演化规律。结果表明:花岗岩粗糙裂隙渗透率与围压呈对数负相关关系。当温度分别为25、150和180℃时,加载阶段裂隙渗透率分别减小78%、90%和92%,卸载阶段裂隙渗透率仅分别恢复63%、26%和19%;这表明加卸载过程粗糙裂隙面在应力作用下发生了塑性变形,导致裂隙渗透率出现永久性衰减。当温度由25℃增加到150℃和180℃时,加卸载过程塑性变形导致粗糙裂隙的渗透率衰减率由15%分别上升至64%和73%;这表明塑性变形与裂隙表面接触微凸体发生的矿物颗粒破碎有关,高温条件下其影响更为显著。To study the effect of thermal-mechanical coupling on fracture permeability evolution of enhanced geothermal systems(EGS),flow-stress loading and unloading coupling experiments were carried out on granite samples with rough single fracture under the normal temperature(e.g.,25℃)and high temperature(e.g.,150℃and 180℃)conditions,respectively.The confining pressure of loading and unloading processes was between 5 MPa and 30 MPa.The evolution law of fracture permeability induced by elastic-plastic deformation was analyzed during stress loading and unloading.The results show that the fracture permeability has a logarithmic negative correlation with the confining pressure.When the temperature was 25,150 and 180℃,the fracture permeability decreased by 78%,90%and 92%in the loading stage,and only recovered by 63%,26%and 19%in the unloading stage.This indicated that the rough fracture surface has occurred plastic deformation during loading and unloading processes,which leads to permanent attenuation of fracture permeability.When the temperature increased from 25℃to 150℃and 180℃,the permeability attenuation caused by plastic deformation increased from 15%to 64%and 73%,respectively.This indicated that the effect of plastic deformation on the fracture surface is related to the crushing of mineral particles,which becomes more significant in high temperatures.

关 键 词：增强型地热系统 地热裂隙 热-力耦合作用 流动实验 裂隙渗透率 

分 类 号：P641[天文地球—地质矿产勘探]