沁水盆地南部高阶煤层多分支水平井钻井工艺

沁水盆地南部高阶煤层多分支水平井钻井施工中遇到了以下难题:①井壁稳定性差,容易发生井下复杂事故；②煤层易受污染,储层保护难度大；③岩屑携带不畅,井壁严重失稳；④缺乏先进适用的钻井工具及仪器.为解决上述问题,分析了多分支水平井井眼轨迹及分支结构优化设计、复合造穴、水平井与洞穴井连通、井眼轨迹控制、充气欠平衡钻井等关键技术...

Multi-branch horizontal well drilling in the southern Qinshui Basin with high-rank coal beds

Great difficulties have been encountered in the drilling of multi-branch horizontal wells in the Qinshui Basin with high-rank coal beds.(1)Poor wellbore stability will result in kinds of downhole accidents;(2)Reservoir protection becomes difficult due to the easily contaminated coal seams;(3)Unsmooth cuttings carrying leads to severe wellbore instability;(4)There is lack of advanced and appropriate drilling tools and instruments.In view of this,this paper first focuses on the involved key techniques includi...