薄至中厚煤层群矿区采动卸压煤层气抽采井优化设计  

Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group

作　　者：徐昂 桑树勋[1,2,3,4] 周效志 韩思杰[3,4] 陈捷[1,2,5] 冯云飞 娄毅[6] 颜智华 高为 XU Ang;SANG Shuxun;ZHOU Xiaozhi;HAN Sijie;CHEN Jie;FENG Yunfei;LOU Yi;YAN Zhihua;GAO Wei(Key Laboratory of Coalbed Methane Resource and Reservoir Formation Process,Ministry of Education,Xuzhou 221008,China;School of Mineral Resource and Geoscience,China University of Mining and Technology,Xuzhou 221116,China;Carbon Neutrality Institute,China University of Mining and Technology,Xuzhou,221008,China;Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization,Xuzhou 221008,China;Guizhou Research Center of Shale Gas and CBM Engineering Technology,Guiyang 550081,China;Guizhou Panjiang Coalbed Methane Development and Utilization Co.,Ltd.,Guiyang 550081,China)

机构地区：[1]煤层气资源与成藏过程教育部重点实验室,江苏徐州221008 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]中国矿业大学碳中和研究院,江苏徐州221008 [4]江苏省煤基温室气体减排与资源化利用重点实验室,江苏徐州221008 [5]贵州省煤层气页岩气工程技术研究中心,贵州贵阳550009 [6]贵州盘江煤层气开发利用有限责任公司,贵州贵阳550081

出　　处：《煤炭科学技术》2025年第3期385-399,共15页Coal Science and Technology

基　　金：国家自然科学基金资助项目(42030810);贵州省科技计划资助项目([2022]ZD001-05);贵州省科技创新人才团队资助项目(黔科合平台人才-CXTD[2022]016)。

摘　　要：利用煤层气井对采煤过程中邻近煤层卸压煤层气抽采是一种高效的瓦斯综合治理与煤层气开发手段。查明采动覆岩应力−裂隙场演化特征,并据此开展煤层气井优化设计是提高卸压煤层气抽采效率的关键。以黔西山脚树煤矿221015工作面为工程场景和实例,基于地质−工程模型构建与工程数据分析,阐明了覆岩层内及层间应力演化特征,探讨了覆岩裂隙与增渗区分布形态,优化了煤层气井井位部署、井身结构设计及增产措施。研究表明:研究区煤系岩石力学性质频繁强弱交互的地质特征提高了卸压煤层气抽采效果。关键层逐次破断后,工作面上方5~20 m层段为贯通裂隙带,带内富集的大量游离态甲烷可跨层运移产出,为煤层气井主气源带。工作面上方20~45 m层段属弯曲下沉带内微裂隙发育带,具有近2000 m^(3)/d的单层煤产气潜力。该带卸压煤层气以层内运移为主,并积聚了裂隙带煤层气。压实区沿工作面走向的边界切线、压实区沿工作面走向的边界切线与回风巷间的中轴线、裂隙区边界线围成的区域是最有利的井位部署位置。采用高强度水泥固井与扩孔完井的“二开”井或采用筛管悬挂完井的“三开”井井筒稳定性好,可保障煤层气井长期抽采工作。优化方案为黔西地区煤矿采动区卸压煤层气抽采井日产气35000 m^(3)的突破提供了技术支撑,显著减弱了工作面瓦斯突出风险。基于多层叠置含煤层气系统的地质特点,“合层压裂排采+采动卸压抽采”的“一井多用”模式可作为“提产增效”的重点研究方向。In mining areas,utilizing coalbed methane(CBM)wells to extract stress relief coalbed methane from adjacent coal seams is an efficient strategy.To enhance CBM extraction,it is vital to reveal the dynamics of stress and fracture fields evolution and optimization well locations and structure.Taking No.221015 coalface in Shanjiaoshu coal mine as the study area.By integrating geo-engineering models and engineering data,the stress distribution within and between the overburden was elucidated,the distribution of fracture and the per-meability increased zone in the overburden were elucidated,and the well location,structures and enhancement measures were designed.The research demonstrates that:The frequent alternation of lithological properties in the coal measure strata in the study area enhanced the mining influence on overburden.As the key strata progressively fail,the zone located 5−20 meters above the coalface were the fracture zones,in which a large amount of free methane can be migrated and produced across layers,serving as the primary gas source zone of CBM well.The 20−45 meters interval above the coalface belonged to the microfracture zone in the bending subsidence zone,possessing a gas production potential of nearly 2000 m^(3)/d from adjacent coal seams within a single layer.In this area,stress relief CBM primarily mi-grates intra-strata and accumulates methane originating from the fracture zone.Optimal well site locations was enclosed by tangential line of the compaction zone along the direction of the coalface and the center line between tangential line of the compaction zone and the re-turn airway,and boundary lines around fractured zones.Meanwhile,the two-or three-stages structure wells with high strength cement ce-menting and using reaming or screen suspended completion have good stability,which can guarantee long-term extraction work of CBM well.The optimized extraction well scheme provides technical support for achieving a gas production breakthrough of 35000 m^(3)/d from in mining areas of Qianxi reg

关 键 词：薄至中厚煤层群 采动区 覆岩“三带”分布 煤层气井优化设计 

分 类 号：P618[天文地球—矿床学]