抽采长度对煤层气开采效果的影响分析

发布时间：2018-04-27 02:32

本文选题：采矿工程 + 煤层气开采　；参考：《岩石力学与工程学报》2017年01期

【摘要】：运用自主研发的多场耦合煤层气开采物理模拟试验系统,开展三维应力状态下煤层气开采物理模拟试验,分析不同抽采长度条件下煤储层内气体压力参数的动态演化规律。研究表明:不同抽采长度条件下,气体压力都是从钻孔中心周围开始下降的;抽采前期气体压力下降显著,随着抽采时间的延伸,各测点气体压力值变化速率减小;随着抽采长度的增加,气体压力梯度较大的区域明显扩大,同时会提高瓦斯的解吸速率,抽采效率提高。抽采断面上的等压线则以钻孔为中心,呈圆环状分布,气体主要是汇流至抽采钻孔,层面流场中等压线则以钻孔为对称轴呈漏斗形分布。抽采长度对突出危险消除区域出现时间影响不大,但随抽采长度增加,消除突出危险性所需时间减少;由于应力集中区应力大、解吸速率慢,消除突出危险性抽采所需时间较其他区长。研究成果可为现场合理布置抽采钻孔,提高抽采效率以及确定合理的抽采时间提供一定的理论依据。
[Abstract]:In this paper, the physical simulation test system of multi-field coupled coalbed methane mining is developed, and the dynamic evolution law of gas pressure parameters in coal reservoir under different extraction length is analyzed. The results show that under different extraction lengths, the gas pressure decreases from the center of the borehole, the gas pressure decreases significantly in the early stage of extraction, and the change rate of the gas pressure decreases with the extension of the extraction time. With the increase of extraction length, the region with larger gas pressure gradient will expand obviously, meanwhile, the desorption rate of gas will be increased, and the extraction efficiency will be improved. The isobaric line in the extraction section is centered on the borehole and distributed in a circular pattern. The gas flows mainly to the pumping hole and the isobaric line in the stratified flow field is distributed in the funnel shape with the borehole as the symmetry axis. The extraction length has little effect on the emergence time of the outburst danger elimination area, but with the increase of the extraction length, the time required to eliminate the outburst danger decreases, and the desorption rate is slow because of the stress in the stress concentration zone. It takes longer than other districts to eliminate the outburst danger. The research results can provide certain theoretical basis for reasonable layout of extraction boreholes, improvement of extraction efficiency and determination of reasonable extraction time.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室;重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室;重庆大学资源及环境科学学院;
【分类号】：TD712

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