页岩气井压裂液进入断层的途径及防控措施  

Leakage path of fracturing fluid into faults and prevention and control measures in shale gas wells

作　　者：张慧[1] 李军[1,2] 张小军 张鑫 连威 ZHANG Hui;LI Jun;ZHANG Xiaojun;ZHANG Xin;LIAN Wei(College of Petroleum Engineering,China University of Petroleum,Beijing 102249,China;China University of Petroleum(Beijing)at Karamay,Karamay 834000,China)

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249 [2]中国石油大学(北京)克拉玛依校区,新疆克拉玛依834000

出　　处：《断块油气田》2021年第6期750-754,760,共6页Fault-Block Oil & Gas Field

基　　金：国家自然科学基金项目“深水油气钻采井筒压力控制基础研究”(51734010);国家自然科学基金企业联合基金项目“海相深层油气富集机理与关键工程技术基础研究”(U19B6003)。

摘　　要：目前,断层滑移被认为是页岩气水平井套管剪切变形的主要原因,因此大多数研究都集中在压裂过程中的流体压力扩散规律上,而忽略了压裂液进入断层的途径。文中基于断层滑移机理,结合非压裂区出现的微地震信号,总结了压裂液进入断层的3种主要途径——水泥环微环隙、近井筒天然裂缝、大尺度天然裂缝,并进行了室内实验、数值模拟和现场分析,论证了套管变形的可能性,最后提出了防控措施。研究结果表明,压裂过程中水力裂缝易被天然裂缝捕获,将流体压力传递至压裂区域远端,产生应力干扰,甚至导致非压裂区的套管变形。采用暂堵转向压裂技术,对压裂液沿断层的滤失具有减缓作用,同时能够增加水力裂缝的复杂程度,从而提高开采效益。At present,fault slip is considered as the main reason for casing shear deformation in horizontal shale gas wells.Therefore,most of the studies are focused on the diffusion law of fluid pressure during fracturing and ignored the path of fracturing fluid into the fault.Based on the fault slip mechanism,combined with the phenomenon of micro-seismic signals in non-fracturing areas,this paper summarizes three paths of fracturing fluid into the fault:micro-annulus between casing and cement sheath,micro-fractures near wellbore,large-scale natural fractures.Correspondingly,laboratory tests,numerical simulation and field analysis are carried out to demonstrate the possibility of casing deformation.Finally,the preventive measures are put forward.The research results show that during the fracturing,hydraulic fractures are easily captured by natural fractures and fluid pressure is transfered to the far end of the fracturing area,causing stress interference and even casing deformation in the non-fracturing zone.The use of temporary plugging and steering fracturing technology can improve the leakage of fracturing fluid into faults,and increase the complexity of hydraulic fractures at the same time,thereby improving the development benefit.

关 键 词：页岩气 断层滑移 套管变形 流体压力扩散 天然裂缝 暂堵转向 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]