面向项目风险控制的煤炭地下气化地质条件分析  

Analysis of geological conditions for risk control of UCG project

作　　者：秦勇 易同生[1] 汪凌霞[2] 金军 周泽[2] 孔维敏[2] QIN Yong;YI Tongsheng;WANG Lingxia;JIN Jun;ZHOU Ze;KONG Weimin(Coal Geology Bureau of Guizhou,Guiyang 550025,China;China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]贵州省煤田地质局,贵州贵阳550025 [2]中国矿业大学,江苏徐州221116

出　　处：《煤炭学报》2023年第1期290-306,共17页Journal of China Coal Society

基　　金：贵州省科技重大专项资助项目(黔科合重大专项字[2021]3002);国家自然科学基金重点资助项目(42130802)。

摘　　要：煤炭地下气化(UCG)是中国煤炭工业发展的必然选择,地质风险控制是UCG项目成败与否的首要基础。立足这一背景,将钻井式UCG项目风险控制总目标分解为建炉地质可行性、气化生产易控性、气化过程安全性、开发生产经济性4个子目标,探讨地质条件与潜在风险之间因果关系,提出了UCG地质分析与评价新思路。分析认为,UCG炉高质量建造体现在井壁稳定性和井眼轨迹可控性2个方面,前者关键地质因素是煤体结构或强度,后者主要受控于煤层厚度、结构、产状及其稳定性。UCG生产易控性地质评价聚焦于2个目标:一是气化工作面推进易控性,倾角适中的煤层有利于UCG工作面推进,燃点过高煤层工作面推进难度较大,复杂煤层结构不利于气化,微构造是UCG过程控制的不利因素;二是UCG层内通道易控性,通道易控性随煤层埋深增大而显著降低,高黏结高膨胀性煤层会严重危害通道畅通程度,高灰熔点和高热稳定性煤层更易保持通道畅通性。UCG过程安全性地质分析同样包括2个方面:其一,UCG生产安全性,涌水量过大带来安全生产隐患,上覆足够厚度隔水层及其稳定性是保障生产安全的关键;其二,UCG环境安全性,UCG地面沉降总体上并不显著,有机物污染潜势与煤种高度相关,中~难挥发性有害元素对地下水环境的危害性需高度关注。UCG开发经济性主要涉及气化有效性、合成气质量、资源可靠性3个方面,与煤的化学反应性、灰分产率、煤田勘查程度、煤炭资源量等因素密切相关,地下气化-煤层气联采则是提高UCG经济性的可探索途径。实际上,多数地质因素均与上述4个UCG风险控制子目标相关联,不同程度上存在交叉影响,需依据相对贡献参与UCG地质评价,其中微断层、煤的黏结性和膨胀性、上覆含水层距离3个因素具有“一票否决”作用,进而提出了面向UCG项目风险控制的地质评价与优�Underground coal gasification(UCG)is an inescapable choice for the development of China’s coal industry,and geological risk control is the primary basis for the success of a UCG project.The general goal of risk control for a drilling-style UCG project is divided into four sub-goals,i.e.,the geological feasibility of geo-reactor construction,the easiness of gasification production,the safety of gasification process and the economy of production.The causal relationship between geological conditions and potential risks is discussed,and a new idea of geological analysis and evaluation of an UCG project is proposed.The analysis shows that the high-quality completion of the UCG wells is reflected in the stability of borehole wall and the controllability of borehole trajectory,in which the key geological factor of the former is the coal-body structure or coal seam strength,while the latter is mainly controlled by the thickness,structure,occurrence and stability of coal seam.The geological evaluation on the controllability of the UCG production focuses on two objectives.One is the controllability of the gasification working face’and the coal seams with moderate dip angles are conducive to the advancement of the face.It is difficult to promote the face of coal seams with high ignition point.The coal seam with complex structure is not conducive to gasification.Micro-structure is unfavorable to the UCG process control.Other is the easiness of channel control in the UCG layer and the easiness decreases significantly with the increase of coal seam depth.The high cohesive and swelling coal seam will seriously endanger the openness of the channel.The coal seam with higher ash melting point and thermal stability is easier to keep the channel unblocked.The geological analysis of the UCG process safety also includes two aspects.One is the safety of the UCG production,the excessive water inflow will cause the hidden risk of production safety,and the key to ensure the safety is to cover an aquiclude with sufficient thickness and

关 键 词：煤炭地下气化 项目风险 地质分析 建炉可行性 生产易控性 过程安全性 生产经济性 

分 类 号：TD84[矿业工程—煤矿开采]