赵庄井田3~#煤层含气量的地质控制因素分析
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摘要
基于沁水盆地南部赵庄井田3号煤层的含气特征,从煤岩煤质、煤阶、有效地层厚度、地质构造、水文地质条件等方面探讨了影响该区煤层含气量的地质控制因素。结果表明:井田内煤层含气量具有由西北向东南逐渐降低的趋势,甲烷浓度变化较大、含气饱和度偏低的特点。宏观上,煤层含气量与有效地层厚度、上覆岩层泥岩比例呈明显的正相关性,局部地区含气量受次级构造影响,具有典型的构造控气特征,地下水对煤层气具有封堵作用,有利于煤层气的保存,只有在局部构造带水力逸散作用使煤层含气量降低。微观上,煤层含气量随挥发分产率、水分+灰分含量的增加具有先增大后减小的趋势,煤层含气量与氮气含量具有此消彼长的关系,在重烃含量高的地区煤层含气量也普遍较低。
Based on gas-bearing property of No. 3 coal seams of Zhaozhuang Block in southern Qinshui Basin,the geological control factors such as petrography and quality,coal rank,buried depth,geologic structures,and hydrogeological conditions,which have influence on the gas-bearing property,were discussed in paper. The results show that the gas content decreases gradually from northwest to southeast,the methane concentrationvaries in a big range,with relatively low gas saturation. On macroscopic view,the distribution of methane content has significantly positive correlation with the effective thickness of strata and shale content,gas content affected by secondary structure in regional,the groundwater condition of coal-bed has a seal which is beneficial to coalbed methane preservation,only in the local structural belt the gas content reduced by hydraulic dissipation. On microscopic view,the gas content in coal-bed is mainly involved in volatile matter,ash content,and water content. Gas content and nitrogen content has a reciprocal relationship,gas content is generally lower in the high content of heavy hydrocarbon areas.
Based on gas-bearing property of No. 3 coal seams of Zhaozhuang Block in southern Qinshui Basin,the geological control factors such as petrography and quality,coal rank,buried depth,geologic structures,and hydrogeological conditions,which have influence on the gas-bearing property,were discussed in paper. The results show that the gas content decreases gradually from northwest to southeast,the methane concentrationvaries in a big range,with relatively low gas saturation. On macroscopic view,the distribution of methane content has significantly positive correlation with the effective thickness of strata and shale content,gas content affected by secondary structure in regional,the groundwater condition of coal-bed has a seal which is beneficial to coalbed methane preservation,only in the local structural belt the gas content reduced by hydraulic dissipation. On microscopic view,the gas content in coal-bed is mainly involved in volatile matter,ash content,and water content. Gas content and nitrogen content has a reciprocal relationship,gas content is generally lower in the high content of heavy hydrocarbon areas.
引文
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[3]孙粉锦,王勃,李梦溪,等.沁水盆地南部煤层气富集高产主控地质因素[J].石油学报,2014(6):1070-1079.
[4]陈召英,王保玉,郝海金,等.寺河区块煤层气井排采特征及抽采效果分析[J].煤炭科学技术,2017,45(7):100-105.
[5]郭盛强.成庄区块煤层气井产气特征及控制因素研究[J].煤炭科学技术,2013,41(12):100-104.
[6]王保玉,白建平,郝春生,等.煤层气地面井压裂-井下长钻孔抽采技术效果分析[J].煤炭科学技术,2015,43(2):100-103.
[7]李劲松,刘建宇,李琛.赵庄煤矿3#煤层水文地质类型划分探讨[J].华北科技学院学报,2015,12(1):6-10.
[8]张群,杨锡禄.平衡水分条件下煤对甲烷的等温吸附特性研究[J].煤炭学报,1999,24(6):566-570.
[9]Crosdale P J,Beamish B B,Valix M.Coalbed Methane Sorption Related to Coal Composition[J].International Journal of Coal Geology,1998(3):147-158.
[10]傅雪海,秦勇,李贵中,等.特高煤级煤平衡水条件下的吸附实验[J].石油实验地质,2002,24(2):177-180.
[11]贺天才,秦勇.煤层气勘探与开发利用技术[M].徐州:中国矿业大学出版社,2007.
[12]朱岳年.天然气中N2的成因与富集[J].天然气工业,1999,19(3):23-27.