摘要
针对我国低透气性煤层瓦斯抽采效果差的问题,提出采用大孔径钻孔对低渗煤层进行瓦斯治理。采用数值模拟的方法研究了大孔径钻孔应力场和塑性区分布特征,得到了大孔径钻孔下瓦斯流动规律。通过对比分析得出不同直径钻孔周边应力和塑性区均呈“蝶状”分布,并且应力和塑性区分布随着钻孔直径增大而增大。裂隙流下的瓦斯运移方向呈现规律性,瓦斯先运移到裂隙,再通过裂隙运移到钻孔,并且裂隙长度越长,瓦斯抽采效果越显著。从透气性系数和负压作用范围两个方面阐述了提高瓦斯抽采效果的原因,验证了大孔径钻孔的可实施性。研究结果为煤矿井下大直径钻孔瓦斯治理提供了理论指导。
In response to the problem of poor gas drainage effect in the low permeability coal seam,it is proposed to use large diameter drilling to extract gas.The numerical simulation method was used to study the distribution of the stress field and plastic zone under large diameter drilling,and the plastic zone was simplified as fractures to study the gas flow law.The comparative analysis shows that the stress distribution and plastic zone are“butterfly-like”at different borehole diameters,and the stress distribution and plastic zone distribution increase with the increase of borehole diameter.The gas migration direction under fracture flow is regular.The gas first migrates to the fracture and then migrates to the borehole through the fracture.The longer the fracture length is the more obvious the gas extraction effect is.The reasons for improving gas drainage effect are expounded from two aspects of permeability coefficient and negative pressure range,and the feasibility of large diameter drilling is verified.The results of this study can guide gas extraction from large boreholes in coal mines.
作者
薛志鹏
XUE Zhi-peng(Safety Training Center of Shanxi Coal Mine,Taiyuan 030012,China)
出处
《煤》
2022年第7期18-21,共4页
Coal
基金
国家自然科学基金(51874122)
河南省科技攻关项目(222102320050)
河南省高校基本科研业务费专项项目(NSFRF210426)。
关键词
应力分布
塑性区
裂隙流
瓦斯抽采
数值模拟
stress distribution
plastic zone
fracture flow
gas extraction
numerical simulation
