低透气性煤层顺层密集钻孔抽采及并管提压系统研究

Research on lift pressure system with combined pipeline and intensive drill⁃hole gas drainage along the layer in low permeability coal seam

  • 摘要: 针对高瓦斯低透气性煤层的瓦斯预抽难题,提出顺层密集大直径钻孔布置和并管提 (负)压的瓦斯强化抽采技术,阐述了顺层密集大直径钻孔布置实现全区域增透的抽采原理。 根 据流体流动的连续性方程和能量方程,建立了区段主管路中流体能量变化的表达式,并得出相应 的能量坡度线。 结合预抽钻孔的“负压-流量”特性曲线,阐明采用并管方式连接主管路提升抽 采负压和增加抽采量的作用机理,并根据实践经验综合确定瓦斯强化抽采技术参数。 现场实践 表明,该技术治理瓦斯效果显著,工作面瓦斯抽采率达55%以上,生产能力由1*2Mt/a增加到 1*8Mt/a,上隅角瓦斯浓度无超限现象,实现了复杂地质条件下的安全高效开采。

     

    Abstract: Aimingattheproblemofgaspre⁃drainageinhighgasandlowpermeabilitycoalseam,the strengthentechnologyofcoalseamgasextractionwasputforwardwhichisthesystemofcombinedpipe⁃ linetoliftthenegativepressureandintensivelargediameterdrill⁃holealongseam*Theextractionprin⁃ cipleofrealizingthepermeableincreasinginallzonebyintensivelargediameterdrill⁃holealongseam wasexplained*Accordingtothecontinuityliquidflowequationandenergyequation,theexpressionof liquidenergychangeswasestablishedtogetliquidenergygradientlinesinsectioncompetent pipe⁃ line*Combinedwiththe“negativepressure⁃flow”characteristiccurveofpre⁃drainagegasdrill⁃hole,the mechanismofincreasethenegativepressureandextractionscalarthroughcombinedpipelinewasclari⁃ fiedandtheparametersofstrengthenextractiontechnologyincoalseamwasconfirmedbypracticalex⁃ perience*Thepracticeshowedthatthistechnicaleffectongovernancegaswasremarkable,thegasex⁃ tractionrateinworkingfacewasabove55% andtheproductioncapacityincreasedfrom1*2Mt/ato 1*8Mt/a*Theuppercornergasconcentrationwasunderthesafetystandard,andthusthesafetyandef⁃
    ficientlyminingincomplicatedgeologicalconditionswasrealized*

     

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