摘要
套管损坏是影响海上高温高压井开发效益的重要原因之一。在准确求解井筒温度场的基础上,考虑地层非均匀地应力、地层高压与热应力的影响,计算套管-水泥环-地层系统耦合热应力状态,分析水泥环、套管性能参数等对套管损坏的影响。结果表明,随着离套管中心径向距离的增加,Mises应力逐渐降低、径向应力呈现"增-减"变化趋势、周向应力呈现"跳跃式"变化,综合确定套管内壁处套管损坏风险最高;考虑高温高压时,套管Mises应力更高,套损风险增大;随着圆周角的变化,Mises应力、剪应力最大值出现于圆周角45°、周向应力最大值出现于圆周角0°;随套管、水泥环弹性模量与热膨胀系数的增大,套管Mises应力逐渐增大。研究成果对于海上高温高压井的套管损坏分析具有一定的指导意义。
Casing failure is one of the important factors affecting the development efficiency of offshore high temperature and high pressure (HTHP) wells.So far,the influence of HTHP on casing stress has not been studied deeply.In this paper,wellbore temperature field was calculated accurately.Then,the coupling thermal stress state of casing-cement sheath-formation system was calculated in consideration of the influence of non-uniform in-situ stress,high formation pressure and thermal stress.Finally,the effects of the performance parameters of cement sheath and casing on the casing failure were analyzed.It is indicated that with the increase of radial distance from the casing center,the Mises stress decreases gradually,the radial stress increases firstly and then decreases,and the circumferential stress presents a "skip" change.It is comprehensively determined that the risk of casing failure is the highest at the inner wall.If HPHT is taken into account,the Mises stress of casing and the risk of casing failure will increase.With the change of circumference angle,the maximum values of Mises stress and shear stress appear at the circumference angle of 45 °,and the maximum circumferential stress appears at the circumference angle of 0 °.With the increase of the elastic modulus and thermal expansion coefficient of casing and cement sheath,the Mises stress of casing increases gradually.The research results are of some guiding significance to the analysis on the casing failure of offshore HPHT wells.
作者
李治衡
刘海龙
王文
张羽臣
张磊
LI Zhiheng;LIU Hailong;WANG Wen;ZHANG Yuchen;ZHANG Lei(Tianjin Branch of China National Offshore Oil Co.,Ltd.,Tianjin 300459,China)
出处
《石油钻采工艺》
CAS
CSCD
北大核心
2018年第A01期129-132,共4页
Oil Drilling & Production Technology
关键词
高温高压
套管
耦合
非均匀地应力
热应力
应力分析
high temperature and high pressure (HTHP)
casing
coupling
non-uniform in-situ stress
thermal stress
