深井、超深井套管磨损后剩余强度分析

建立了磨损套管的三维有限元模型,结合N80套管实际尺寸和材料参数,模拟计算了不同磨损形态、磨损长度及深度对磨损后套管剩余强度的影响。计算结果表明,套管磨损深度和壁厚不变时,磨损套管的剩余抗拉强度与磨损长度成指数反比例关系,剩余抗挤强度与磨损长度成指数正比例关系;当磨损长度一定时,套管剩余抗拉强度和抗挤强度随磨损深度的增加而线性降低。根据数值模拟计算结果得到了磨损套管剩余强度与磨损长度、磨损深度之间关系的计算公式,为校核、计算套管磨损后剩余强度提供了参考。

Study on residual strength of wearing casing in deep and ultra-deep wells

The three-dimension finite element model of wearing casing is established in this paper. Referring to the real dimensions and material parameters of the N80 casing, a simulated calculation is performed on the effect of different forms, lengths and depths of abrasion on the residual strength of casing after abrasion. The calculations show that, when the abrasive depth and wall thickness of casing remain unchanged, the residual tensile strength of wearing casing is in an exponential inverse proportion to its abrasive length, and the residual collapsing strength is in an exponential direct proportion to the abrasive length; when the abrasive length remains fixed, the residual tensile and collapsing strength of casing decreases linearly with the increase of the abrasive depth. The formulas on the relation of the residual strength of the wearing casing to the abrasive length and depth are obtained according to the results of the numerical simulation calculation, providing a reference for checking and calculating the residual strength of the wearing casing.