School of Energy Resources,China University of Geosciences (Beijing) Coal Reservoir Laboratory of National
Engineering Research Center of Coalbed Methane Development & Uilization National Engineering Research
Center,China United Coalbed Methane Co.,Ltd. School of Earth Sciences and Resources,China University of
Geosciences (Beijing)

为全面评价和认识多层合采煤层气井的开发效果,基于韩城矿区不同层位组合方式下煤层气井产能特征,结合无因次产能阶段划分方法,建立了韩城矿区煤层气井开发组合产能分布模式。结果表明:韩城矿区煤层气井多表现为高产水、低产气特征,产能效果亟待提高。无因次产气率在气井排水阶段结束时约为0.3,不稳定产气阶段结束时约为0.6,气井稳定产气阶段结束时约为0.8;产气高峰出现在稳定产气阶段,产水高峰出现在不稳定产气阶段。多层合采较单层排采效果好,双层合采较三层合采效果好,其中含有3号煤层与5、11号煤层的合采井(3+5、3+11、3+5+11)合采效果比只含有5、11号煤层的合采井(5+11)及含砂层合采井效果好。建议增加含有3号煤层合采井的比例以提高气井产能,井位部署及压裂时应避开断层,尤其注意监测裂缝是否沟通含水层。

In order to evaluate and understand coalbed methane( CBM) well development effect with multi-layer drainage comprehensively,based on multi-layer draina ge coalbed methane( CBM) well productivity characteristics in Hancheng Mining Area,the productivity distribution modes under different coal seam combinations were also established with dimensionless production stage classification method.The results indicated that most of the CBM wells were observed with high water rate and low gas rat e which needs to be improved urgently.At the end of the water drainage stage,the dimensionless gas rate was about 0.3 while it was about 0.6 when the unstable gas pro duction stage was over. Meanwhile,when end of stable gas production stage occurs,the value of dimensionless gas rate was about 0.8. The gas rate peak appeared in sta ble gas production stage and water rate peak could be found in unstable gas production stage. The effect of the multilayer drainage was better than that of the single layer and the two-layer drainage was better than that of the three-layer. When No. 3 coal was contained in production layers( No. 3+5,3+11,3+5+ 11),the productivity of CBM well was higher than those of No.5+ 11 and sand layers. In the process of the subsequent CBM development,it was considerable to increase the proportion of the wells which p roduced gas from the No.3 coal to improve well productivity. In addition,when well was placed and fractured,it was also important to avoid faults,especially paid more atten tion to monitor whether the coal seams were communicated with aquifers by cracks.

国家科技重大专项资助项目(2011ZX05038-001)；国家自然科学基金资助项目(41272175)；中央高校基本科研业务费专项基金资助项目(2652015331)；