晋城矿区王坡井田地面瓦斯抽采效果影响因素

Influencing factors of surface gas extraction effect in Wangpo minefield of Jincheng mining area

晋城矿区王坡井田地面瓦斯抽采效果差,为了查明原因,指导今后地面抽采工程施工,将研究区煤层气资源赋存条件与抽采效果较好的临近成庄井田进行了对比分析,并对排采井水质进行检测,同时在井下进行压裂裂缝形态观测。综合分析认为,煤层瓦斯资源丰度和储层条件是影响王坡井田抽采效果的主要内在基础因素;大量发育的陷落柱破坏了煤层气封闭条件并增强了地下水的补给,造成抽采井的排水降压难度大;井下裂缝观测表明,压裂裂缝顺煤层与顶板弱应力面水平延展,导致储层压裂改造效果欠佳。建议加强对研究区的瓦斯赋存分布特征及陷落柱发育规模深入研究,以指导后期地面井瓦斯抽采工程施工。

The effect of surface gas extraction in Wangpo minefield of Jincheng mining area is poor.In order to find out the causes and to guide the construction of future surface gas extraction,the occurrence conditions of CBM resources in the study area were analyzed and compared with those of adjacent Chengzhuang minefield where the extraction effect is good,the quality of the produced water was tested,at the same time the fracture forms were observed underground.The comprehensive analysis indicated that the abundance of coal gas resources and the reservoir conditions were the major intrinsic basic factors influencing the gas extraction effect in Wangpo minefield;Great amount of developed collapse columns have destroyed the confining conditions of CBM and enhanced groundwater recharge,resulting in the difficulties in depressurization by water drainage of extraction wells.Underground fracture observation showed that the fractured fractures extended horizontally along coal seams and the weak stress plane of seam roof,inducing the poor effect of fracturing and transformation of the reservoir.It is recommended to study deeply the characteristics of gas occurrence and distribution as well as the development scale of collapse columns in the study area to later construction of surface gas extraction wells.