摘要
针对赵庄煤矿地面煤层气垂直压裂井抽采效果不理想、瓦斯治理难度大的问题,以赵庄煤矿3号主采煤层作为研究对象,开展了现场采样测试、抽采模式分析、数值模拟、现场试验,提出采用自由水平段耦合分段压裂井的煤层气抽采新模式。研究结果表明:3号煤层由上部稳定的硬煤和下部相对稳定的软煤组成,且分层明显,在上部硬煤层中布置的水平井能够有效提高钻遇率,所形成的自由水平段能够有效避免固井作业对煤层产生的污染和伤害,同时采用水力喷砂进行射孔、油套环空加砂压裂建立裂缝网络,形成地层产气通道。MFrac Suite压裂软件数值模拟结果揭示了采用大排量、中砂比的水力喷砂射孔压裂工艺能够在垂向上撕裂煤层,所形成的裂缝能够从上部硬煤中穿越进入下部软煤,形成多组复杂不规则的垂向裂缝,同时在水平方向上能够形成一定长度的裂缝,能够实现良好的压裂改造效果。现场工程试验结果验证了该模式具有良好的产气效果,最高日产气量超过5100m^(3),截至2020年1月31日,已累计产气超300万m^(3),抽采效果显著。
As the Zhaozhuang Coal Mine’s surface CBM vertical fracturing wells and gas extraction is not satisfactory,taking Zhaozhuang Coal Mine No.3 main mining seam as the research object,by carrying out field sampling test,extraction mode analysis,numerical simulation,field test and other research work,a CBM drainage mode of free section coupled with staged hydraulic fractured well is put forward.Research indicates:the No.3 coal seam is composed of a stable hard coal structure on the upper part and a relatively stable soft coal structure on the lower part,with obvious stratification,the horizontal well deployed in the upper hard coal seam can effectively increase the drilling rate,and the free horizontal section formed can effectively reduce the pollution and damage to the coal seam caused by cementing operations,at the same time,hydraulic sand blasting is used for perforation and oil casing annulus reinforcement,sand fracturing establishes a network of fractures and forms formation gas channels.The numerical simulation results of MFrac Suite fracturing revealed that the hydraulic sandblasting and perforating fracturing process with large displacement and medium sand ratio can tear the coal seam vertically,from the upper hard coal into the lower soft coal,multiple sets of complex and irregular vertical fractures are formed,and at the same time,a certain length of fractures are formed horizontally,which can achieve a good fracturing effect.Field test engineering results have verified that this model has a favorable gas production effect,the maximum daily gas production volume exceeds 5100m^(3).As of January 31,2020,the cumulative gas production has exceeded 3 million m^(3),and the extraction effect is remarkable.
作者
刘磊
LIU Lei(Xi’an Research Institute,China Coal Technology and Engineering Group Co.,Ltd.,Xi’an 710077,China)
出处
《煤炭工程》
北大核心
2021年第12期87-91,共5页
Coal Engineering
基金
国家自然科学基金资助项目(41972167)
“十三五”国家科技重大专项资助项目(2016ZX05045002)
陕西创新人才推进计划–科技创新团队项目(2018DT-039)。
关键词
自由水平段
分段压裂
煤层气
赵庄煤矿
free segment
staged hydraulic fracture
coal seam gas
Zhaozhuang Coal Mine
