堵漏封堵层对裂缝稳定性影响模拟研究  

Numerical Investigation into the Influence of Plug Zone on Fracture Deformation in Lost Circulation Controlling

作　　者：李松[1,2] 康毅力[1] 李大奇[3] 佘继平[1] 王业众[2] 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都601500 [2]中国石油西南油气田分公司工程技术研究院,四川广汉618300 [3]中国石化石油工程技术研究院,北京100101

出　　处：《天然气地球科学》2015年第10期1963-1971,共9页Natural Gas Geoscience

基　　金：国家重点基础研究发展规划("973"计划)项目课题"深井复杂地层漏失与井壁失稳机理及预测"(编号:2010CB226705);国家科技重大专项"复杂地层漏失诊断及完井方法研究"(编号:2011ZX05005-006-008HZ)联合资助

摘　　要：钻井过程中井筒液柱压力波动致使地层裂缝扩展变形,钻井液中的固相颗粒及堵漏材料随钻井液漏失进入裂缝并在缝内沉积逐渐形成封堵层。封堵层形成后会影响裂缝变形、井周切向应力及裂缝尖端应力强度因子的重新分布,并且这些裂缝变形因素的变化又影响着封堵层的稳定性,导致井漏反复发生。应用有限元法模拟了封堵层对裂缝变形、井周切向应力及裂缝尖端应力强度因子等裂缝变形因素的影响,探索了封堵层存在下的裂缝变形行为,深化了裂缝变形研究。封堵层阻止液柱压力传递进裂缝,降低裂缝变形程度、井周切向应力及裂缝尖端应力强度因子,增强了裂缝力学稳定性。模拟研究量化了封堵层对裂缝变形程度的影响,为优选堵漏材料、科学开展防漏堵漏提供了理论依据。Fractures intersected with borehole are extremely which causes the fissures evolved loss channels. This causes plug the deformable fracture stably, and results in lost circula circulation materials （LCMs） is also simulated and investigat sensitive to borehole pressure fluctuations, the solid particles in drilling fluid failing to tion frequently. The plug zone formed by lost ed,which changes the deformable behavior of fractures,hoop stress on wellbore and stress intensity factor in fracture tip. The simulation results reveal that the plug zone has the function of preventing wellbore pressure propagation from fluid pressure in frac- ture to increase, reducing the deformable degree of fracture, weakening the hoop stress on wellbore, and de- creasing the stress intensity factor in fracture tip. The deformable behavior of fracture in fractured-vuggy carbonate formations is investigated clearly, and the deformable degree of fracture is predicted, which can provide theoretical basis for mud loss controlling and improve the knowledge of the fracture deformation.

关 键 词：封堵层 裂缝变形 井周应力 井漏 应力强度因子 

分 类 号：TE258[石油与天然气工程—油气井工程]