摘要
在能源结构转型与“双碳”目标驱动下,煤炭地下气化(UCG)作为煤炭清洁化利用的关键技术备受关注。UCG完成后形成的燃空区凭借其独特的高渗透裂隙网络、残焦强吸附性及高温高压地质环境,展现出作为新兴CO_(2)地质封存储载体的显著潜力。本研究基于此,系统探究了燃空区形成机制与空间演化规律,揭示了CO_(2)在腔体内的多相态运移特征:早期受浮力驱动在盖层下聚集形成构造圈闭,中期通过扩散作用被多孔残焦物理吸附,长期则与碱性灰渣发生矿化反应生成稳定碳酸盐。为评估封存安全性,采用热−流−固−化(Thermo−Hydro−Mechanical−Chemical,以下简称THMC)多场耦合数值模拟技术,刻画了CO_(2)迁移诱发的岩体应力场畸变与裂隙扩展行为,并识别出盖层完整性、注入压力阈值及腔体规模为影响长期稳定性的核心控制参数。关键结论表明:燃空区封存技术通过耦合碳捕集(CCS)可显著降低UCG碳足迹,为煤炭低碳开发提供新范式;但当前仍面临残渣非均质分布导致的注气效率衰减、CO_(2)−围岩热力化耦合损伤机制不明、盖层裂隙长期演化预测精度不足等瓶颈。未来研究需重点突破多相态运移—矿化反应动力学量化模型构建,研发裂隙动态监测与“回形充填体”优化技术,以推动该技术从潜力认知迈向工程应用。
Driven by energy structural transformation and the"dual carbon"goals,underground coal gasification(UCG)has drawn significant attention as a key technology for clean coal utilization.Research has shown that UCG,with its unique high−permeability fracture network,strong adsorption capacity of residual coke,and high−temperature geological environment,has significant potential as an emerging CO_(2) geological storage medium.This study systematically investigated the formation mechanism and spatial fixation of the combustion cavity,revealing the multiphase migration characteristics of CO_(2) within the cavity:early on,driven by buoyancy,it accumulates beneath the caprock to form structural traps.Locally,it is physically adsorbed by residual coke through diffusion,and over time,it undergoes mineralization reactions with alkaline ash residues to form stable carbonates.To assess storage safety,this study employed Thermo−Hydro−Mechanical−Chemical(THMC)multi−field coupled simulation simulation technology to characterize the rock mass stress distortion and fracture propagation induced by CO_(2) migration.Furthermore,it identified caprock defects,injection pressure threshold,and cavity size as key control parameters influencing long−term stability.Key conclusions indicate that Coupling with carbon capture and storage(CCS)can significantly reduce the carbon footprint of UCG,offering a new paradigm for low−carbon coal development.However,current challenges include reduced gas injection efficiency due to heterogeneous residue distribution,the lack of a mechanism for thermal damage associated with CO_(2)−surrounding rock formation,and inaccurate predictions of further caprock fracture formation.Future research should focus on developing multiphase transport−mineralization kinetic reaction models,investigating dynamic fracture monitoring,and optimizing"annular backfill structures"to advance the potential of this technology toward engineering applications.
作者
辛林
谭一
杨敏
王若男
牛茂斐
闵令冉
刁垌彤
杨冰玉
张凯榕
宋永坤
李欣颖
XIN Lin;TAN Yi;YANG Min;WANG Ruonan;NIU Maofei;MIN Lingran;DIAO Tongtong;YANGBingyu;ZHANG Kairong;SONG Yongkun;LI Xinying(Shandong University of Science and Technology,Qingdao 266590,Shandong,China;State Key Laboratory of Disaster Prevention and Ecology Protection in Open−pit Coal Mines,Shandong University of Science and Technology,Qingdao 266590,Shandong,China)
出处
《矿产保护与利用》
2025年第5期50-64,共15页
Conservation and Utilization of Mineral Resources
基金
国家自然科学基金资助项目(52374211,52304190,52304060)
山东省自然科学基金项目(ZR2023QE117,ZR2024QE029)
山东省泰山学者青年专家项目(TSQN202507183)。
关键词
煤炭地下气化
燃空区
CO_(2)封存
地质封存
CO_(2)迁移规律
多场耦合
underground coal gasification
combustion cavity
carbon dioxide storage
geological storage
CO_(2)migration patterns
multi−field coupled simulation
