摘要
煤炭采出后,采空区中仍蕴藏着丰富的煤层气资源,其资源评价与开发利用具有环保和资源双重意义。近几年来,在山西晋城、西山和阳泉等矿区开展了地面钻井抽采采空区煤层气的积极探索,但在采空区煤层气地面开发过程中,往往因煤矿采空区积水、上覆岩层承压涌水等原因,导致地面钻井不产气或抽采气量低。以山西晋城岳城矿为例,研究不同采煤工艺下的采空区煤层气赋存特征、采空区积水和采空区裂隙带岩层渗透率对采空区煤层气地面开发的影响,提出采空区井布置原则和抽采技术,为解决三开空气钻进过程中岩粉进入裂隙带堵塞采空区煤层气运移通道问题,探索用水力冲孔方法提高采空区裂隙带岩层渗透率方面的应用。研究表明,煤矿采空区井布井原则:(1)采空区井应布置在采空区积水区域之外;(2)针对房柱式采煤形成的采空区空间形态,采空区井应避开保护煤柱最终完钻至采空区空间内;针对长臂式垮落法采煤形成的采空区空间形态,采空区井最优钻井区域为“O”形圈边界连线和采场边界之间靠近终采线一侧。研发了一种煤矿采空区井排水采气一体化抽采系统,该抽采系统实现了采空区井底积水抽排和煤层气抽采同步进行,解决了采空区上覆岩层承压涌水造成煤层气产量下降问题,抽采系统优化前后采空区井煤层气抽采量增加33.3%。探索性地将水力冲孔运用于解决钻井岩屑造成的采空区裂隙带岩层渗透率下降问题,工程试验结果表明,水力冲孔改造前后采空区井日均抽采量最高增长率为11.30%,提出了采用泡沫欠平衡钻井技术解决钻井岩粉侵入采空区裂隙带的建议。
There are still rich CBM resources in goafs after coal mining,and the resource evaluation,development and utilization have dual significance of environmental protection and resources.In recent years,ground drilling has been actively explored in Jincheng,Xishan and Yangquan mining areas in Shanxi Province to extract CBM in the goafs.However,in the process of ground development of CBM,due to water accumulation in the goafs,confined water gushing from overlying strata and other reasons,there is no gas production or low gas extraction from ground drilling.Taking Yuecheng Coal Mine in Jincheng,Shanxi as an example,this paper studies the occurrence characteristics of coal-bed methane in goafs under different coal mining technologies,the influence of goaf water accumulation and rock permeability in goaf fracture zones on the ground development of coal-bed methane in the goafs,and puts forward the layout principle and extraction technology of goaf wells.To solve the problem that rock powder enters the fracture zones blocking the migration channel of coal-bed methane in goafs during the three-open air drilling,the application of hydraulic punching method is explored to improve the rock permeability in goaf fracture zones.The research shows that the well layout principle of the coal mine goafs is as follows:(1) The goaf wells should be arranged outside the goaf water accumulation area;(2) For the spatial form of goafs formed by room-and-pillar mining,the goaf wells should avoid the protective coal pillar and finally complete drilling into the goaf space.In view of the spatial form of goaf formed by long arm caving method,the optimal drilling area of goaf well is the “O” circle boundary connection line and the stope boundary near the terminal line.An integrated drainage and gas extraction system for goaf wells in coal mines was developed.The drainage system realized the simultaneous drainage of accumulated water at the bottom of goaf wells and the extraction of CBM,and solved the problem of CBM production decline caused by the pressure water inflow of the overlying strata in goafs.The CBM extraction amount of goaf wells increased by 33.3% after the optimization of the drainage system.The hydraulic punching is applied to solve the problem of permeability decline in fractured zones of the goaf caused by drilling cuttings.The engineering test results show that the maximum increase rate of daily average extraction of goaf wells before and after hydraulic punching transformation is 11.30%.The suggestion of using foam under-balanced drilling technology to solve the problem of drilling rock powder invading into fractured zones of the goaf is put forward.
作者
周显俊
李国富
李超
王争
李江彪
ZHOU Xianjun;LI Guofu;LI Chao;WANG Zheng;LI Jiangbiao(State Key Laboratory of Coal and Coalbed Methane Co-mining,Jincheng 048012,China;Yi’an Lanyan Coal and Coalbed Methane Co-mining Technology Co.,Ltd.,Taiyuan 030031,China;Shanxi Lanyan Coalbed Methane Group Co.,Ltd.,Jincheng 048006,China)
出处
《煤田地质与勘探》
CAS
CSCD
北大核心
2022年第5期66-72,共7页
Coal Geology & Exploration
基金
山西省应用基础研究项目(201701D221233)
山西省科技重大专项项目(20201102001)
山西省揭榜招标项目(20201101001)。
关键词
煤矿采空区
煤层气
地面抽采
井位布置
井身结构
coal mine goaf
coalbed methane
surface extraction
well location arrangement
well bore configuration
