摘要
通过建立非线性有限元模型,分析了不同条件下不同套管内壁临界应力的变化规律,得到了不同生产内压下的临界地应力方程。套管内壁临界应力的分布随着最小地应力的增大及临界地应力非均匀系数的减小,其变化规律由不规则形状最终趋于一缩腰椭圆形。套管岩压外载随着地应力非均匀系数的减小,其形状趋于椭圆,与最大、最小地应力的方向相反。根据中原油田的地应力资料,普通套管无法承受异常高的非均匀地应力,应开发专用于岩膏层油水井的特种套管。
The distribution of interior critical stress of different casings under different circumstances are analyzed by way of the establishment of nonlinear FEM, also the critical in-situ stress equations of different operating interior pressures are achieved. With the increment of minimum in-situ stress and the decreasing of critical in-situ stress coefficient, the distribution of interior critical stress of casing is different, the change rule is that irregular shape tend to be a constricted elliptical. The shape of external load due to salt formation tends to be a elliptical with the decreasing of critical in-situ stress coefficient, which is contrary to the direction of maximum and minimum in-situ stress. According to the data obtained in Zhongyuan oil field, ordinary casing can＇t bear such extremely high non-uniform in-situ stress, so special casing must be developed to the production of oil and water wells which are situated in gypsum-salt rock.
出处
《石油矿场机械》
2008年第3期65-69,共5页
Oil Field Equipment
关键词
套管损坏
岩膏层
非均匀地应力
临界应力
岩压外载
casing failure
gypsum-salt rock
non-uniform in-situ stress
critical stress
external load due to salt formation
