油页岩原位加热井下温度场及热应力研究  

Temperature field and thermal stress of downhole system for in-situ heating on oil shale

作　　者：高孝巧[1] 杨浩[1] 熊繁升 吕健国 

机构地区：[1]中国地质大学(北京),北京100083 [2]国土资源部深部地质钻探技术重点实验室,北京100083

出　　处：《断块油气田》2014年第3期373-377,共5页Fault-Block Oil & Gas Field

基　　金：国家潜在油气资源产学研用合作创新项目"油页岩勘探开发利用"(OSR-04-07);深部大陆科学钻探装备研制"深孔井壁稳定研究"(201011082);大学生创新创业训练计划国家级项目(201211415016)

摘　　要：油页岩原位加热开采工艺技术已被广泛应用。在加热期间,井下高温造成套管、水泥环、地层组合体发生热膨胀,使套管产生较大的热应力和热位移,从而可能使其发生变形损坏。文中使用Comsol Multi-Physics软件对油页岩原位加热井井筒至地层的温度分布进行模拟,并分析规律;同时,基于弹性力学和热力学理论,推导耦合系统的热应力、热位移的理论计算公式,分析热应力、热位移径向分布规律,以及开展应力影响参数探讨。研究认为,油页岩原位加热井下温度分布服从指数衰减规律;组合体最大VonMises应力出现在套管内壁,随着井径向距离的增加,应力值大幅度降低;径向热位移随井径向距离增加先增大后减小,最大值出现在地层中;径向热应力先增大后减小,最大值出现在套管外壁上;理想的固井水泥环应为"高强度、低弹性";实际热采工程中,应保证套管抗屈服强度下,使用低弹性模量的套管材料,以降低热应力。Abstract： The ieehnology of in-situ heating on oil shale has been widely used. When the well is in high temperalure, it will cause the thermal expansion of casing. At the same time, the casing will prodnee a larger thermal stress and thermal displacement, which can lead to the damage of casing and the unstability of the borehole. The simulation of the temperature from the wellbore to formatinu of insitu heating on oil shale is developed by Co,nsol Muhi-Physies software In analyze the law. The formulas nf thermal stress and displacement for casing-eement-ormation coupling system are derived based on the elastic mechanics and lhermodynamics. The thermal stress and radial thermal displacement distribution of the coupling system are ealeulaled, and the influencing parameters of the thermal stress are discussed. The study shows that the distribution of temperature obeys exponential decay laws. The maximum VonMises stress of assembly is located on easing internal wall. In the meanwhile, with the radial distance increasing from easing center, the stress firstly decreases. The radial displacement and stress increase, then decrease, and the maximum values are located on formation and casing external wall respectively. The ideal property of concrete sheath shouhl be of high strength and low stiffness. In the actual engineering, in order to reduce the lhermal stress, it should assure that the easing is in tensile yiehl slrength and the casing materials with low elasticity modulus are used.

关 键 词：油页岩 耦合系统 热应力 温度分布 Comsol数值模拟 

分 类 号：TE345[石油与天然气工程—油气田开发工程]