【摘要】 针对长寿命油气井的安全可靠性问题,提出了套管柱的抗震可靠性研究。通过对地震烈度和对应加速度的随机性描述,得出了地震烈度及对应加速度的概率分布规律和分布参数;同时,通过对套管几何尺寸和管材力学性能的随机性描述,明确了套管外径、壁厚、屈服强度、弹性模量、泊松比等随机变量的概率分布规律和分布参数。建立了地震作用下套管柱的力学模型;借助于振型分解反应谱理论和等效静载荷法,完成了地震作用下套管等效应力的计算方法研究;通过结构可靠性理论建立了地震作用下套管的可靠度计算模型;采用Monte-Carlo的Latin Hypercube数值模拟方法完成了实际套管抗震可靠度的计算。计算结果表明,套管柱的抗震安全指标近似呈最小极值I型分布,即一般情况下地震作用对套管柱损坏的影响不大,但对于较高地震设防烈度地区的长寿命油气井而言,地震对套管柱安全可靠性的影响不容忽视。更多还原

【Abstract】 Seismic reliability analysis of casings string was brought forward in pursuit of safety of long life oil & gas wells. The randomness of earthquake was described, and the regularities and parameters of distribution of earthquake intensity and the acceleration of ground motion were obtained. In addition, the regularities and parameters of distribution of casing’ outside diameter, wall thickness, Young’ modulus, and Poisson’s ratio were clarified by means of description of the randomness of casing’s geometric dimensions and mechanical properties. The mechanical model of the casing string under the earthquake action was founded. The study of calculation method of equivalent stress of casing string under the earthquake action was completed in virtue of the spectral modal analysis theory and the method of equivalent static load. The reliability model of casing string under the earthquake action was established by dint of structure reliability theory. The seismic reliability of practical casing string was calculated by means of Latin Hypercube stochastic simulation method based on Monte-Carlo method. The calculation result shows that casing string’s security index follows the minimum extreme value type I distribution, and the influence of earthquake on casing string is always very low. However, the influences of earthquake on casing string are very serious in long life oil & gas wells in areas where the seismic fortification intensity is higher.更多还原