岩土力学2018，Vol.39Issue(1)：103-111,122,10.DOI:10.16285/j.rsm.2016.0081
卸压区不同钻孔长度抽采条件下瓦斯运移特性试验
Test on gas migration characteristics during coal bed methane exploitation under different lengths of drilling hole in distressed zone
摘要
Abstract
The research on gas migration law during coal bed methane (CBM) exploitation is beneficial to understand the source of gas,impact of coal seam position on gas production and the law of gas pressure decay,thus providing foundation for design of exploitation time and the position and length of drilling hole.Using the multi-field coupling testing system for CBM exploitation developed by the authors,physical simulation experiments of CBM exploitation under different lengths of drilling hole in distressed zone were carried out,and relative gas flow speed and direction were analyzed.The results show that the initial stage of exploitation is the main contribution period to gas production and the surrounding area of drilling hole is the main contribution area to gas production,because gas pressure gradient is high and thus gas flows fast.Gas flow has the highest speed at the distressed zone.Existence of concentrated stress zone makes the relative flow speed attenuate quickly,and also creates a barrier to original stress zone,leading relative gas flow speed to be zero.Relative gas flow speed decreases with time while the migration direction does not change much because relatively stable seepage channels are formed at the beginning of exploitation.Due to gas pressure drop that leads gas pressure gradient and relative gas flow speed to decrease,the uncertainty of migration direction rises.With the length of drilling hole growing,the relative gas flow speed increases in the distressed zone,so it is meaningful to moderately lengthen the drilling hole.关键词
瓦斯抽采/物理模拟/瓦斯相对流动速度/偏离角/抽采时间/钻孔长度Key words
CBM exploitation/physical simulation/relative gas flow speed/deviation angle/exploitation time/length of drilling hole分类
矿业与冶金引用本文复制引用
许江,苏小鹏,彭守建,刘义鑫,冯丹,刘龙荣..卸压区不同钻孔长度抽采条件下瓦斯运移特性试验[J].岩土力学,2018,39(1):103-111,122,10.基金项目
国家科技重大专项项目(No.2016ZX05044002) （No.2016ZX05044002）
国家自然科学基金(No.51474040,No.51434003).This work was supported by the National Science and Technology Major Project (2016ZX05044002) and the National Natural Science Foundation of China (51474040,51434003). （No.51474040,No.51434003）
