摘要
采用有限元法研究了岩盐地层中水泥环的弹性模量和厚度对套管强度的影响规律。将"套管-水泥环-地层"简化成一个平面系统,以等效的弹性地层代替蠕变的岩盐地层,并将地应力分为均匀和非均匀两种情况,而将水泥环的弹性模量和厚度设为可调参数。研究结果表明:在"套管-水泥环-地层"系统中,最大应力总是发生在套管的内壁;当水泥环的厚度一定时,其弹性模量存在一个中间值,等于该值时套管中的最大应力达到峰值;单纯增加水泥环的厚度不一定能够改善套管的受力状况,有时甚至会恶化,只有当水泥环的弹性模量大于一定数值后,增加其厚度才能改善套管的受力状况。
The effects of cement sheath elasticity modulus and thickness on the casing strength in salt beds were investigated using finite element method. Plane system was used to simplify the ＂casing-cement sheath-formation＂ system and to replace creep halite formations with the equivalent elasticity formation. Geological stress would he classified into uniform and non-uniform geologic stress, and cement sheath elasticity modulus and thickness were defined as adjustable parameter. The results show that the maximal stress will appear on the inner wall of the casing in the ＂casing-cement sheath-formation＂ system; the maximal stress will peak when cement sheath elasticity modulus was equal to intermediate value in certain value of thickness of cement sheath; Increasing the thickness of the cement sheath is not always reducing the stress of the casing, sometimes it could deteriorate the casing stress. When the elastic modulus of cement sheath achieves some value, increasing the thickness of cement sheath could decrease the casing stress.
出处
《石油钻探技术》
CAS
北大核心
2009年第5期58-61,共4页
Petroleum Drilling Techniques
基金
国家自然科学基金项目"空气钻井直井易斜机理及其控制技术研究"(编号:50674065)
上海市科委项目"西部地区高陡构造油气资源快速钻探技术研究"(编号:061658035)资助
关键词
岩盐层
水泥环
弹性模量
套管强度
有限元法
salt rock
cement sheath
modulus of elasticity
casing strength
finite element method
