层间弱接触面对穿煤层页岩气井稳定性的影响  

Influence of weak interlayer contacts on the stability of shale gas wells transiting minable coal seams

作　　者：梁顺[1] 李学华[1] 姚强岭[1] 杨栋[2] 

机构地区：[1]中国矿业大学矿业工程学院,深部煤炭资源开采教育部重点实验室,江苏徐州221116 [2]太原理工大学采矿工艺研究所,山西太原030024

出　　处：《采矿与安全工程学报》2015年第3期471-477,共7页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51474208,51304208);江苏省普通高校研究生科研创新计划项目(CXZZ12_0951);煤炭资源与安全开采国家重点实验室自主研究课题项目(SKLCRSM12X01)

摘　　要：不同性质岩层间的弱接触面是影响边坡、地下巷道及硐室等岩土结构稳定的关键因素之一,煤层开采引起的覆岩运动是导致采动影响区内垂直页岩气井破坏的主要原因,针对垂直穿过长壁煤柱的页岩气井井筒稳定性问题,利用二维地质模型,对井筒剪切、离层、拉伸及压缩等变形量进行了预测,对比分析了层间弱接触面对穿煤层垂直页岩气井稳定性的影响;根据煤柱内不同布井位置条件下井筒各类变形的大小及轴向分布规律,得到了井筒沿轴向易于失稳的危险高度并优化了布井位置。结果表明,FLAC程序中的接触面单元能够很好地表征由采动引起的、沿软硬岩层间弱接触面出现的动力响应,对井筒的主要失稳模式——剪切失稳展现效果良好。Weak contact between layers with different properties is one key factor affecting the stability of engineering structures, e. g., slopes, underground roadways, and chambers. The movement of overly-ing strata induced by coal mining is the main reason for the damage of vertical shale gas wells drilled within the mining affected areas. By using two-dimensional geological model, predictions have been made about various well deformations, e.g., shear slippage, bed separation, tension and compression, and the effect of weak contacts between layered strata on the stability of gas wells piercing a coal seam has been analyzed. The axial heights at which the gas well is prone to failure has been acquired through the analysis of the axial distribution characteristics and various deformation of well holes in the different positions of coal pillars, according to which the position of the well has been optimized thereafter. Re-sults indicate that the “interface” element in FLAC is excellent in realizing the possible deformation responses occurring at weak interfaces caused by coal mining, and it is very commendable in characte-rizing the shear failure mode, which is the major mode of well instability.

关 键 词：复合岩层 弱接触面 采动影响 气井稳定性 

分 类 号：TD325[矿业工程—矿井建设]